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The following excerpts are from articles or books that I have recently read. They caught my interest and I hope that you will find them worth reading. If one does spark an action on your part and you want to learn more or you choose to cite it, I urge you to actually read the article or source so that you better understand the perspective of the author(s).
Human Soul

[This excerpt is from The Astonishing Hypothesis, written by Francis Crick.]

      Many educated people, especially in the Western world, also share the belief that the soul is a metaphor and that there is no personal life either before conception or after death. They may call themselves atheists, agnostics, humanists, or just lapsed believers, but they all deny the major claims of the traditional religions. Yet this does not mean that they normally think of themselves in a radically different way. The old habits of thought die hard. A man may, in religious terms, be an unbeliever but psychologically he may continue to think of himself in much the same way as a believer does, at least for every-day matters.

Our Nerve Cells

[This excerpt is from The Astonishing Hypothesis, written by Francis Crick.]

      The Astonishing Hypothesis is that “You,” your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll’s Alice might have phrased it: “You’re nothing but a pack of neurons.” This hypothesis is so alien to the ideas of most people alive today that it can truly be called astonishing.

How Fast Will the Antarctic Ice Sheet Retreat?

[These excerpts are from an article by Eric J. Steig in the 7 June 2019 issue of Science.]

      There is no longer any serious scientific doubt that the retreat of glaciers in Antarctica will eventually cause several meters of sea level rise, unless the emission of anthropogenic greenhouse gas is reduced substantially. By one estimate, each kilogram of carbon emitted as CO2 will ultimately result in the melting of more than two metric tons of Antarctic ice. But how quickly this will happen remains highly uncertain, with the implications for society ranging from relatively moderate to possibly catastrophic….They show that the interaction of the ice sheet with the solid Earth—an important aspect of the problem not adequately captured by previous work—may slow down retreat.

      Antarctica is losing ice mainly through the thinning, calving, and retreat of ice streams, the fast-flowing glaciers that drain the larger, slower-moving ice sheet into the ocean. A handful of ice streams in the Amundsen Sea region of West Antarctica…contribute nearly 10% of the current global sea level rise of 3.4 mm/ year. The ice discharge from Thwaites Glacier…, the largest glacier in this region, has more than doubled in recent years. The ongoing retreat of Amundsen Sea glaciers was initiated by the flow of warm, deep water onto the continental shelf, probably driven by anomalous wind conditions in the mid-20th century. Warm ocean water melts the glaciers 41.- from below, causing acceleration and grounding line retreat (the grounding line is the point where the glacier goes afloat to become an ice shelf).

      …The farther the glacier retreats, the deeper the water in which it terminates, and the more readily it melts and calves. Once retreat is initiated, atmosphere and ocean conditions become less important and the nonlinear dynamics of the glacier dominates its behavior. This makes the future behavior of such glaciers inherently difficult to predict….

Women of Color Face Double Dose of Bias

[These excerpts are from an article by Katie Langin in the 7 June 2019 issue of Science.]

      Bradley Miller is more likely to be hired than Jose Rodriguez. Mang Wei (David) is more competent than Jamal Banks. And both Miller and Wei are more competent and hirable than Maria Rodriguez or Shanice Banks.

      These postdoc job candidates are fictional. But the differences in how they’re viewed based on name alone—despite identical CVs —by a sample of professors are real. That's according to a recent study that unearths evidence of racial bias in biology and a combination of gender and racial bias in physics, highlighting both the pervasive nature of various biases in science as well as important disciplinary differences.

      …In 2012, Moss-Racusin published a similar study, which found that biology, chemistry, and physics faculty members who reviewed applications for a lab manager position favored applicants named John over otherwise identical applicants named Jennifer. The new study…is an important advance because it manipulates race as well as gender….

      …she and her colleagues decided to focus on the postdoc period because it is “a critical part of the pipeline,” and also “a part of the pipeline where there are almost no checks and balances” to prevent bias. Principal investiga-tors typically review postdoc applications in isolation….

      Faculty members in biology viewed male and female applicants to be similarly competent and likely to be hired….But in physics, it was a different story: Faculty members preferred male applicants, rating them one point higher on competence—on a nine-point scale—and two points higher on hirability.

      Faculty members in both disciplines exhibited racial bias. In physics, Asian and white applicants were given higher competence and hirability ratings than black and Latino applicants. In biology Asian and white applicants were viewed as more competent than black applicants. Asian applicants were also viewed as more hirable than black and Latino applicants. (Ratings for Latino competence and white hirability didn’t statistically differ from other groups.)

      In physics, black and Latina women were doubly disadvantaged, rated three points lower in hirability than white and Asian men….

      …In physics, the number of women has “stayed stubbornly low” despite a surge of female scientists in other disciplines, and a lack of awareness of bias may be one factor….

A New Narrative for the Ocean

[These excerpts are from an editorial by Jane Lubchenco and Steven D. Gaines in the 7 June 2019 issue of Science.]

      …For most of human history, people considered the ocean so immense, bountiful, and resilient that it was impossible to deplete or disrupt it. The overarching narrative was, “The ocean is so vast, it is simply too big to fail.” This mindset persists today, bringing even more intense, unsustainable uses of the ocean that reflect ignorance; the allure of new economic opportunity; or the need for food, resources, and development. However, the folly of this too-big-to-fail narrative has become glaringly obvious through overpowering scientific evidence of depletion, disruption, and pollution. Climate change, ocean acidification, habitat destruction, overfishing, and nutrient, plastic, and toxic pollution are insidious. These changes threaten the most vulnerable people; the economic prosperity, quality of life, and opportunities for everyone; and the well-tieing of the ocean’s amazing life forms. Problems appear too complex, vested interests too powerful, and system inertia too great, especially as demands on the ocean escalate. A new narrative has arisen: “The ocean is massively and fatally depleted and disrupted. The ocean is simply too big to fix.” The result? Depression and lack of engagement and motivation.

      Yet despite the undeniable challenges, hints of a new ocean mindset are emerging. Many powerful solutions already exist and could be scaled up. Opportunities abound to develop new solutions that are based on efficiency; incentives, technology; biotechnology, and regenerative and holistic approaches. Moreover, because the ocean is central to the functioning of the planet and human well-being, many ocean solutions could bring substantial co-benefits to address poverty, hunger, economic development, inequity; peace, security, coastal resilience, and climate mitigation and adaptation. For example, reforming fisheries to “fish smarter, not harder” can help restore ocean ecosystems; reduce impacts of climate change; and enhance food security, job creation, and poverty alleviation. Combining remote sensing, artificial intelligence, big data, machine learning, transparency, and new policies can minimize illegal fishing. Enabling sustainable aquaculture—especially of low trophic species—could contribute substantially to food security; with a much smaller environmental footprint than that of terrestrial animal production. Creating fully and highly protected, well-designed marine protected areas will safeguard biodiversity, replenish the ocean, and help mitigate and adapt to climate change and ocean acidification. Incorporating ocean actions into the climate agenda is essential to reducing greenhouse gas emissions and adapting to climate disruption. Expanding the range of effective solutions and scaling them globally requires scientists to engage actively with communities, fishers, businesses, nongovernmental organizations, managers, and policy-makers so that solutions are complementary; integrated, effective, and rapid.

      A new narrative does not automatically change the status quo but, if widely adopted, can reset expectations and liberate ingenuity. Yes, the challenges are fierce, and the future is unpredictable. But here is an opportunity to replicate, accelerate, and escalate existing successes while driving innovative and transformative changes….Now is the moment for more scientists to pivot from simply documenting the tragedy underway to also creating scalable solutions.

      It is time for a new ocean narrative that says, “The ocean is so central to our future. It’s too important to neglect.” In creating a new solution space for the ocean, we can also address broader global problems. In healing the ocean, we can heal ourselves….The ocean is not too big to fail, nor is it too big to fix. It is too big to ignore.

The Rise of Animals

[These excerpts are from an article by Rachel A. Wood in the June 2019 issue of Scientific American.]

      …For decades scientists thought that complex animals—multicellular organisms with differentiated tissue types— originated in the Cambrian explosion. To be sure, a riot of novel forms burst into existence during this time, including the ancestors of many of today’s major animal groups. But recent discoveries from Siberia, Namibia and elsewhere show that complex animals actually got their start millions of years before the Cambrian explosion, during the last chapter of the Precambrian, known as the Ediacaran. Among these finds are the oldest known creatures with external and internal skeletons composed of mineralized tissue, a pivotal evolutionary innovation seen in many modern-day animals.

      The presence of these armored creatures so far back in time-550 million years ago—indicates that the ecological and environmental pressures thought to have driven the Cambrian explosion were in fact at work long before then. Figuring out how these factors shaped the evolution of the earliest complex animals in the Ediacaran is key to understanding the astonishing burst of diversification that followed in the Cambrian. The Cambrian fossil record has been the subject of intense study for more than 150 years. Thus, the broad global patterns of what Cambrian fossils appeared when—and where—are relatively well established: similar fossils turned up on many continents at around the same time, and they followed the same succession of evolutionary changes more or less synchronously. But only now, with the discoveries of the older Ediacaran fossils, are we starting to see the roots of the Cambrian explosion.

      Gratifyingly, we are also beginning to puzzle out why it happened when it did, thanks in part to the development of new geochemical techniques that have revolutionized our understanding of the changing chemistry of the oceans in the Ediacaran-Cambrian world. Insights from the emerging fossil and geochemical records have just recently been integrated to show how the planet’s biosphere, geosphere, hydrosphere and atmosphere—together known as the Earth system—may have operated during this interval. But already we can paint a striking picture of how the seafloor became successively populated by ever more complex creatures tens of millions of years before the Cambrian explosion, setting the stage for the rise of animal life as we know it….

      The oldest candidate animal fossils, which hail from a sequence of rocks in southern China called the Lantian Formation and are possibly as old as 635 million years, are similarly contested….

      The oldest animal remains that almost everyone can agree on are fossils from Newfoundland that date to about 571 million years ago, shortly after the last regional “Snowball Earth” glaciation that encased much of the planet in thick ice. These earliest known representatives of the Ediacaran biota were dominated by soft-bodied creatures up to a meter in height or width. Some took the form of large, featherlike fronds with vertical stalks that rooted them to the seafloor; others sprawled across the ocean bottom, their flat bodies exhibiting a fractal architecture, with branching units that showed the same patterns at all scales. All these body plans maximize surface area, suggesting that these animals absorbed nutrients directly from the surrounding water.

      This modest variety of fauna prevailed for more than 10 million years. But then the pace of animal evolution began to accelerate. The fossil record indicates that after around 560 million years ago, the Ediacaran biota diversified to include mobile forms that inhabited shallow seas. Some of the fossils preserve scratch marks that suggest the animals were eating algal mats by grazing. Others may have dragged themselves across the algae, absorbing nutrients from the underside of their bodies. The first simple burrows also appear at around this time, evidence that animals had started to move and disturb the sediment of the seafloor.

      Fast-forward to around 550 million years ago, and the oldest fossils preserving external and internal skeletons suddenly appear in limestone rocks (which consist mainly of calcium carbonate). These fossils are already diverse in size and form, and they show up in such far-flung locales as Siberia, Brazil and Namibia. The presence of skeletons in so many unrelated animal groups around the world at this point in time is testament to a major driving evolutionary force operating on a global scale. We do not know for sure what this force was. But we have an idea. Making a skeleton is energetically expensive, so for an animal to undertake such an endeavor the benefit must outweigh the cost. Animals may produce a skeleton for many reasons, but by far the most common is the need for protection from predators. Although there is no fossil evidence of predators from this time period, it stands to reason that the appearance of skeletons might reflect the first widespread occurrence of animals that ate other animals.

      …has shown that Cloudina had a variety of growth styles. It could attach to mats made of microbes that bound the soft sediment of the seafloor, or it could anchor itself to layered mounds of cyanobacteria. Most important of all, Cloudina individuals could actually cement themselves to one another to form a reef. This finding has established Cloudina as one of the oldest reef-building animals, pushing back the record of this way of life by some 20 million years.

      Whether Cloudina was related to modern reef builders such as corals remains uncertain. But we do know that like reef-building corals, it lived in proximity to a number of other animals. Hints of this intimate association have come from other skeletal fossils found in rocks of the same age as those that contain Cloudina fossils….

      These observations are significant because reef building represents an important ecological innovation. By growing closely together and even cementing to one another, individuals can become mechanically stronger, rise above the seafloor away from competitors, enhance feeding efficiency and gain protection from predators. Like the earliest skeletons, then, the appearance of reefs in the Ediacaran fossil record may signal rising, complex ecological pressures. The Cambrian explosion, and indeed an arms race between predator and prey, had already begun.

      …Simple, immobile creatures, such as sponges, may need less oxygen than mobile animals, and they certainly require far less of the stuff than active, fast-swimming predators do. We have borne this variation in mind in the course of our investigations.

      Fortunately for us, many new geochemical methods for estimating how much oxygen existed in these ancient seas have been developed in recent years. One especially powerful technique—Fe speciation— harnesses the characteristics of the various compounds of iron, which behave differently depending on whether oxygen is present or not. This method allows us to see at a local scale where—and when—there was enough oxygen to support complexlife. Studies carried out using this approach have led to a broad consensus: dissolved oxygen in the oceans probably reached a threshold or series of thresholds during the Ediacaran that allowed animals to diversify by meeting their increasing metabolic demands as they became more mobile and active….

      Periods of increased anoxia on the seafloor coincide with some well-known mass extinctions, such as the one that punctuated the Permian period 252 million years ago, killing off more than 90 percent of all marine species. But several major diversifications—including those in the Ediacaran-Cambrian, the Ordovician 100 million years later and the mid-late Triassic about 247 million years ago—began during long intervals of dynamic shallow marine anoxia….

      It is far easier for animals to form a skeleton of limestone—the material that makes up the skeletons and shells of many modern marine creatures—when seawater oxygen levels exceed 10 micromoles per liter. Perhaps soft-bodied animals were only able to evolve these calcium carbonate skeletons once oxygen levels reached such a threshold, allowing formerly isolated oases to expand, connect and achieve stability on a global scale….

Air Inequality

[These excerpts are from an article by Andrea Thompson in the June 2019 issue of Scientific American.]

      Harlem and the South Bronx have some of the highest asthma rates in New York City. And these predominantly black and Hispanic neighborhoods—studded with smokestacks and crisscrossed by grid locked highways—are emblematic of a large body of research showing clear racial disparities in exposure to air pollution.

      …even though black and Hispanic people in the U.S. are exposed to more air pollution than white people, these groups consume less from the industries generating much of that pollution….

      The study also found that these disparities persist despite substantial overall reductions in air pollution in recent decades….

      The researchers focused on fine particulate matter with a diameter of 2.5 microns or less (PM2.5), generated by construction, fires and the combustion of fossil fuels. These particles can contain hundreds of different chemicals and can penetrate deep into the lungs, contributing to heart and lung disease. As part of its study, the team estimated that 102,000 people die prematurely every year from PM2.5 emissions from human-made sources (as opposed to wildfires or other natural sources). That number is nearly double the amount of people who die annually from car crashes and murders combined….

      …The results from this study, he adds, emphasize the need to undo the legacy of previous policies and decisions that placed polluting infrastructure disproportionately in low-income and minority communities….

      Scientists, legislators and communities will need to jointly work out which policies and regulations can tackle overall pollution while reducing these inequities….

Calculust

[These excerpts are from an article by Steve Mirsky in the June 2019 issue of Scientific American.]

      …For anyone who vowed that their calculus textbook would be the last thing they’d ever read on the subject, reconsider: “I’ve written Infinite Powers in an attempt to make the greatest ideas and stories of calculus accessible to everyone,” Strogatz notes in the introduction. Then, throughout the book, he gently explains the basics—and gives a historical context that makes for a fascinating read even if you skip the math parts completely. Like you may have done with your textbook.

      The history includes the fact that the word “calculus” comes from the Latin root calx, meaning a “small stone.” “A reminder of a time long ago,” Strogatz writes, “when people used pebbles for counting and thus for calculations.... Doctors use the same word for gallstones, kidney stones, and bladder stones.” In my younger days, I studied derivatives and integrals, but I don’t recall learning until I read Infinite Powers that both of the two 17th-century geniuses usually credited with the invention of calculus, Isaac Newton and Gottfried Wilhelm Leibniz, “in a cruel irony ... died in excruciating pain while suffering from calculi—a bladder stone for Newton, a kidney stone for Leibniz.” At least it was just hyperbole if you ever complained in school that calculus was killing you….

      What evolved over the millennia became the math that gave us modernity “Without calculus, we wouldn’t have cell phones, computers, or microwave ovens,” Strogatz writes. “We wouldn't have radio. Or television. Or ultrasound for expectant mothers, or GPS for lost travelers. We wouldn’t have split the atom, unrav-eled the human genome, or put astronauts on the moon….”

Modern Math Meets Fairy-Tale Physics

[These excerpts are from an article by Andrew Robinson in the 31 May 2019 issue of Science.]

      When Charles Darwin published his theory of evolution by natural selection, he used only words—no mathematics. The same was true of Alfred Wegener's first description of his theory of continental drift. Even Dmitti Mendeleev’s first publication of the periodic table used no mathematics, merely a simple numbering system for the chemical elements.

      In physics, by contrast, sophisticated mathematics played an integral part in the publication of Isaac Newton’s laws of motion; James Clerk Maxwell’s analysis of electromagnetism; Albert Einstein’s theory of relativity; and the quantum mechanics of Paul Dirac, Werner Heisenberg, and Erwin Schrodinger….

      Einstein changed his mind about the ranking of mathematics in physics over three or four decades, as Farmelo reveals in an excellent historical section covering Newton to the 1970s. While developing his 1905 special theory of relativity and his quantum theory, Einstein regarded mathematics as a tool, not as a source of ideas. But later, while struggling with his general theory of relativity, mathematical concepts such as Bernhard Riemann’s geometry of curved space provided Einstein with crucial new ideas. Even so, his loyalty remained with physics….

      However, from the late 1920s until his death, while Einstein was searching for a unified field theory of gravity and electromagnetism, mathematics alone struck him as capable of explaining the structure of the universe. In 1933, he provocatively told an Oxford audience in a lecture, “On the method of theoretical physics”—note his use of “the”—“It is my conviction that pure mathematical construction enables us to discover the concepts and the laws connecting them which give us the key to the understanding of the phenomena of nature”

      During this period, Einstein was generally criticized for his lack of interest in new experimental data from nuclear physics, his lack of sympathy for quantum mechanics, and his obsession with mathematics. Farmelo sympathizes with Einstein’s controversial 1933 claim, while adding that pure mathematical construction must be consistent with relativity and quantum mechanics….

Scientific Leaders Explore Pathways to Climate Solutions

[These excerpts are from an article by Anne Q. Hoy in the 31 May 2019 issue of Science.]

      Climate change is altering ocean ecosystems and impacting Earth’s land surfaces. Yet strategies to address such challenges largely focus on land activities when broader responses offer more power-ful solutions….

      Drawing from an array of scientific disciplines; Lubchenco and Moniz each pointed to the effectiveness of multidisciplinary scientific approaches and collaborative responses to climate change, including those that reach into business and policy arenas….

      In building a verbal bridge between transformations facing the world’s land surfaces and those confronting the oceans, Lubchenco said that success dealing with climate change can only be accom-plished by taking on the risks to land and the oceans….

      Already, the oceans are warming, growing more acidic, holding less oxygen, rising due to higher water temperatures, generating more storms, producing fewer fish stocks, and becoming more polluted from plastics—factors depleting and disrupting the oceans….

      At risk are the beneficial powers of the oceans: the production of more than half the planet's oxygen, absorption of more than 90% of excess heat entrapped by greenhouse gas emissions, and absorp-tion of almost half the carbon dioxide emitted by human activities. Such repercussions…endanger coastal habitats and ocean creatures from wetlands to whales.

      Restoring rapidly disappearing mangrove forests, tidal marshes, and seagrass meadows and protecting coastal areas—which touch 78% of the world's countries—can play an active role in eliminating greenhouse gas emissions….Over a decade and a half beginning in 2000, for instance, the deforestation of mangrove ecosystems, among the best carbon sequestration systems, resulted in the release of 122 million tons of carbon into the atmosphere.

      The effectiveness of ocean “biological pumps” that move carbon around and store it on the ocean floor, due to such things as the submersion of whale carcasses, is weakening. Restoring whale populations could rebuild the ability of oceans to absorb some 160,000 tons of carbon each year….

      Revamping global fisheries responsible for releasing 170 million tons of carbon dioxide into the atmosphere in 2011 and overhauling the shipping industry responsible for 2.6% of the world's carbon emissions in 2016 would deliver significant benefits. Adapting fisheries would expand seafood yields by 40%, increase ocean fish stocks by 5%, and boost industry economic gains by 30%, benefits that would contribute to climate change responses….

      With a focus on energy innovations, Moniz called for adoption of low-carbon electricity generation systems, including advanced nuclear technologies, implementation of energy efficiency practices across economic sectors, and transformative carbon capture and storage techniques. Such approaches…need to be part of a viable climate change response plan.

      Moniz proposes solutions that recognize the diversity of regional energy systems and implement energy efficiency across sectors of transportation, industry, electricity, buildings, and agriculture….

A Call to Climate Action

[These excerpts are from an editorial by Jonathan T. Overpeck and Cecilia Conde in the 31 May 2019 issue of Science.]

      The science is clear, students are striking, and publics around the globe are demanding a new level of leadership to tackle the climate crisis before it is too late. Climate extremes are inflicting serious economic losses on nations, and climate-driven issues such as sea-level rise, regional aridification, food shortages, disease spread, and massive biodiversity loss only promise ever-worsening costs. Progress has been too slow since 195 countries signed the 2015 Paris Agreement committing to hold the increase in the global average temperature to well below 2°C above preindustrial levels. To prevent planetary climate disaster, we must all work to speed up bold initiatives that ensure a rapid exit from the era of fossil fuels, and drive carbon dioxide and other greenhouse gas emissions to the atmosphere down to zero in a manner that benefits everyone on the planet, not just a few.

      Much attention has been focused on promoting the transition to low-carbon energy because of the role that fossil fuel combustion has played in fouling the air and disrupting climate. Moreover, the technology needed to electrify the planet using renewable energy is already, or close to being, cheaper than fossil fuel or nuclear energy, so the existing fossil fuel power plants and fossil-fueled transportation can be phased out completely within two decades. Investment in new fossil fuel infrastructure must cease as existing natural gas and nuclear plants serve only as temporary bridges to a cleaner-energy world. At the same time, every economic sector must innovate to become more energy efficient and decarbonize. With continued innovation, the effective management of marine, coastal, agricultural, forest, and other carbon-sequestering systems can help offset those greenhouse emissions that cannot be eliminated quickly.

      The circle of solutions to address the climate crisis must quickly widen and include effective ways to soften the blows of climate change that are already inevitable. Solutions must strive to enable communities, businesses, societies, and natural systems to become resilient and adapt to the changing climate. The rapid expansion of adaptation strategies around the globe requires greater integration of academic research knowledge with the insight gained from real-world practice, and this means placing greater priority on partnership between academ-ics and nonacademics….The top priority must remain the elimination of the greenhouse gas emissions that are driving climate change, and greater emphasis must be placed on positive synergies between mitigation and adaptation actions, especially those that maximize the protection of biodiversity and soils.

      The climate crisis requires societal transformation of a scale and rapidity that has rarely been achieved. Indeed, the last time such a change took place was sparked by global economic depression and World War II. What enabled action then was a perceived existential threat and broad support in society. Today, we are faced with such a threat, but widening wealth disparities and special interests impede the needed change. The solution to the climate crisis thus requires a strong commitment to equity and justice, to indigenous peoples and future generations, and to a global transformation that vastly increases the number of those who benefit while dramatically reducing the number of those who do not. This is true at national scales, and also at the planetary scale. Only by working together across divides, only by working to empower others, and only by making it a top priority now can the community of nations avoid catastrophic climate change while creating a more sustainable and just 21st century….

What to Do about Plastic Pollution

[These excerpts are from an editorial by the editors in the June 2019 issue of Science.]

      From the bags that find their way to the ocean and into the stomachs of whales to the straws that hurt turtles to the microscopic shards and synthetic fibers that have been found in the remote Arctic, plastic permeates the planet.

      The problem of plastic pollution has gotten dramatically worse as production has ramped up from two million metric tons a year in 1950 to more than 300 million metric tons a year today without much thought to what happens once it is discarded. The thousands of polymers that fall under the catchall label “plastics” never disappear. They merely degrade into smaller pieces called microplastic. A 2017 study in Science Advances estimated that of all the plastic ever produced, 90 percent is still around, mainly in landfills or out in the environment (the rest has been incinerated). Bans on single-use plastic such as bags and straws have become a popular policy around the world to rein in plastic use. But although some of these rules have reduced waste in places, including Ireland and California, they do not directly address production and can send users to alternatives that are not much friendlier to the environment.

      Researchers have learned enough about the flow of plastic waste to know it poses a widespread environmental problem. Plastic causes physical harm to animals and could combine with other threats to endanger vulnerable species. There is also concern about humans inhaling and ingesting microplastic. We must do a better job of stanching the flood. Doing that means tackling two broad goals: considerably reducing the amount of plastic we produce and improving the recycling and reuse of what we make.

      The U.S. must be a bigger part of these solutions. Blame is too often laid solely at the feet of rapidly developing Asian countries that lack robust waste-management systems, and we forget the role that the U.S. plays not only in producing plastic but by exporting millions of tons of the waste to Asia. With China no longer accepting imports of much recyclable waste, it has forced a reckoning in the U.S., with the local authorities responsible for an overwhelmed recycling system turning to landfills and incinerators. Those options can have other environmental impacts and perpetuate the creation of virgin plastic from fossil fuels, instead of reusing and recycling existing plastic. Only 9 percent of plastic in the U.S. is now recycled, according to the Environmental Protection Agency.

      Federal and state governments should step up to help streamline and shore up the nation’s disjointed recycling system. This could be done, for example, by standardizing what can be recycled and putting limits on additives such as coloring, which is expensive to remove and can make plastic less valuable to a recycler. Governments could also fund recycling and composting infrastructure in communities that otherwise might not be able to afford it Such investments could spur American innovation in the area, for example, setting the stage for wider use of compostable plastic, which can currently only be properly broken down in industrial facilities.

      Many researchers also say plastic product manufacturers need to be pushed beyond their present voluntary commitments to reduce plastic waste with incentives that will make them bear more of the cost of that waste….

      We need comprehensive solutions, not just Band-Aids that cov-er up the symptoms but ignore the roots of the plastic problem.

Half-Earth

[These excerpts are from “Half-Earth: Our Planet’s Fight for Life” which is written by Edward O. Wilson.]

      …Our population is too large for safety and comfort. Fresh water is growing short, the atmosphere and the seas are increasingly polluted as a result of what has transpired on the land. The climate is changing in ways unfavorable to life, except for microbes, jellyfish, and fungi. For many species it is already fatal….

      We were not inserted as ready-made invasives into an edenic world. Nor were we intended by providence to rule that world. The biosphere does not belong to us; we belong to it. The organisms that surround us in such beautiful profusion are the product of 3.8 billion years of evolution by natural selection. We are one of its present-day products, having arrived as a fortunate species of Old World primates. And it happened only a geological eyeblink ago. Our physiology and our minds are adapted for life in the biosphere, which we have only begun to understand. We are now able to protect the rest of life, but instead we remain recklessly prone to destroy and replace a large part of it.

      …As a consequence of human activity, it is believed that the current rate of extinction overall is between one hundred and one thousand times higher than it was originally, and all due to human activity. In 2015 an international team of researchers finished a careful analysis of the prehuman rates and came up with a diversification rate ten times lower in genera (groups of closely related species). The data, when translated to species extinctions, suggests species extinction rates at the present time are closer to one thousand times higher than that before the spread of humanity. The estimate is further consistent with an independent study that detected a similar downward shift in the rate of species formation in prehumans, as well as in their closest relatives among the great apes.…

      Reproduction is obviously necessary, but it is a bad idea, as Pope Francis I has pointed out, to continue multiplying like rabbits. Demographic projections suggest that the human population will rise to about eleven billion or slightly more before the end of the century, thereafter peak, and begin to subside. Unfortunately for the sustainability of the biosphere, per-capita consumption is also destined to rise, and perhaps even more steeply than human numbers. Unless the right technology is brought to bear that greatly improves efficiency and productivity per unit area, there will be a continued increase in humanity’s ecological footprint, defined as the area of Earth’s surface each person on- average needs. The footprint is not just local area, but space scattered across land and sea, in pieces for habitation, food, transportation, governance, and all other services down to and including recreation.

      …Clearing a forest for agriculture reduces habitat, diminishes carbon capture, and introduces pollutants that are carried downstream to degrade otherwise pure aquatic habitats en route. With the disappearance of any native predator or herbivore species, the remainder of the ecosystem is altered, sometimes catastrophically. The same is true of the addition of an invasive species….

      Humanity has delivered a blow to the planet not even remotely approached by that of any other single species. The full scale of the assault, in common parlance of the Anthropocene called “growth and development,” began at the start of the Industrial Revolution. It was foreordained by the extermination of most of the mammal species in the world more than ten kilograms in weight, collectively called the megafauna, a process begun by Paleolithic hunter-gatherers and thereafter increased in stages enabled by technological innovation. The decline of biodiversity has been more like the gradual dimming of light than the flick of a switch. As the human population multiplied and spread around the world, it almost always strained local resources to their local limits. Doubling in numbers, then doubling again, and yet again, people fell upon the planet like a hostile race of aliens. The process was pure Darwinian, obedient to the gods of unlimited growth and reproduction. While the creative arts yielded new forms of beauty by human standards, the overall process has not been pretty by anybody else's standards—except bacteria, fungi, and vultures….

      The clear lesson of biodiversity research is that the diversity of species, arrayed in countless natural ecosystems on the land and in the sea, is under threat. Those who have studied the database most carefully agree that human activity, which has raised the species extinction rate a thousand times over its prehuman level, threatens to extinguish or bring to the brink of extinction half of the species still surviving into this century….

      The global conservation movement has temporarily mitigated but hardly stopped the ongoing extinction of species. The rate of loss is instead accelerating. If biodiversity is to be returned to the baseline level of extinction that existed before the spread of humanity, and thus saved for future generations, the conservation effort must be raised to a new level. The only solution to the “Sixth Extinction” is to increase the area of inviolable natural reserves to half the surface of the Earth or greater. This expansion is favored by unplanned consequences of ongoing human population growth and movement and evolution of the economy now driven by the digital revolution. But it also requires a fundamental shift in moral reasoning concerning our relation to the living environment….

      Finally, during the Anthropocene, Earth’s shield of biodiversity is being shattered and the pieces are being thrown away. In its place is being inserted only the promise that all can be solved by human ingenuity. Some hope we can take over the controls, monitor the sensors, and push the right buttons to run Earth the way we choose. In response, all the rest of us should be asking: Can the planet be run as a true spaceship by one intelligent species? Surely we would be foolish to take such a large and dangerous gamble. There is nothing our scientists and political leaders can do to replace the still-unimaginable complex of niches and the interactions of the millions of species that fill them. If we try, as we seem determined to do, and then even if we succeed to some extent, remember we won't be able to go back. The result will be irreversible. We have only one planet and we are allowed only one such experiment. Why make a world-threatening and unnecessary gamble if a safe option is open?

      …In every country where women have gained some degree of social and financial independence, their average fertility has dropped by a corresponding amount through individual personal choice. In Europe and among native-born Americans, it has already reached and continued to hold below the zero-growth threshold of 2.1 children per woman surviving to maturity. Given even a modest amount of personal freedom and an expectation of future security, women choose the option of what ecologists call K-selection, that favoring a small number of healthy well-prepared offspring, as opposed to r-selection, hedging the bet with a larger number of poorly prepared offspring. There won’t be an immediate drop in the total world population. An overshoot still exists due to the longevity of the more numerous per-mother offspring of earlier, more fertile generations.

      There also remain high-fertility countries, with an average of more than three surviving children born to each woman, thus higher than the 2.1 children per woman that yields zero population growth. They include Patagonia, the Middle East, Pakistan, and Afghanistan, plus all of sub-Saharan Africa exclusive of South Africa. The shift to lower fertility can happen during one or two generations. The United Nations biennial report on population in 2014 projected an 80 percent probability that by 2100 the world population, even as it decelerates toward zero growth, will reach between 9.6 billion and 12.3 billion, up from the 7.2 billion existing in 2014. That is a heavy burden for an already overpopulated planet to bear, but unless women worldwide switch back from the negative population trend of fewer than 2.1 children per woman, a turn downward in the early twenty-second century is inevitable….

More Women = Better Energy

[These excerpts are from an article by Katie Mehnert in the June 2019 issue of Scientific American.]

      Climate change is one of the most monumental challenges of our time. But even as it draws increasing calls for action, one of the most important steps we can take still gets far too little attention: we need more women in the energy sector. Only 15 percent of employees in the oil and gas industry are women, and that number is even smaller when you look at higher-paying technical jobs.

      Despite popular belief to the contrary, most leaders in oil and gas do recognize the reality of climate change. And many say they want to do something about it….

      …The Yale Program on Climate Change Communication recently reported that “on average, women are slightly more likely than men to be concerned about the environment and have stronger pro-climate opinions and beliefs.” And for years some women in energy fields have been prominent voices calling for greater action….

      This is true for all forms of diversity: The more different perspectives and life experiences that people bring to boardrooms and work teams, the more innovative ideas they can come up with together.

      …There are still far too many obstacles preventing women from entering the energy field and from reaching their full potential within it. The sector is paying a deep price for its long-term failure to recruit and retain a diverse workforce. When other industries beefed up operations to establish talent pipelines into diverse communities, far too many energy companies did not.

      We also need stronger STEM programs for young women and ample support for those programs from the oil and gas companies….

      To move forward, oil and gas companies also need to erase the negative perceptions many people have of the industry….

      For big ideas to flourish and big actions to follow, people of all backgrounds must be at the table tackling these challenges together. It is time all Americans see themselves represented among the decision makers at the companies that fuel our world. Ill

A Call for Systemic Change for Personalized Learning

[These excerpts are from an article by Joseph J. Cirasuolo in the May 2019 issue of Phi Delta Kappan.]

      …If our schools haven't provided much personalized learning until now it isn’t because educators have lacked the necessary compassion or skills. Rather, it is because they’ve had to operate in a system that constrains such work….

      Or consider the fact that the school system compels all children to follow the same curriculum, instead of learning in a way that best suits the individual child. A significant percentage of children come to the system as active learners who have acquired an enormous number of skills in the first four or five years of their lives only to become quickly classified as slow learners or learning disabled because they do not learn in the way that the system teaches. Again, if the system neglects to provide multiple pathways for children to learn, that is not the fault of educators.

      …If we can change the relationship between time and learning — so that time becomes the variable and learning the constant — then educators will be much better able to help students take greater responsibility for and ownership of their own learning.

      Achieving this deep systemic change is a daunting task. It requires us to replace almost all the underlying assumptions upon which the present system is based….So if we’re serious about making deep'and systemic educational changes, then we have to recognize that this also implies profound cultural changes.

      Of course, cultural change requires persistent and patient efforts….we need to be committed to doing the hard, patient work of systemic and cultural change, taking for granted that our colleagues are also motivated to help children learn. Rather than claiming to be the only real champions of personalized learning, we need to work together to free everybody from a system that prevents us from doing what we became educators to do.

Money, Power, and Education

[These excerpts are from an article by Maria Ferguson in the May 2019 issue of Phi Delta Kappan.]

      …It is not hyperbole to say that the Varsity Blues scandal, in which 50 people were charged with using bribes, false test scores, and other shady methods to influence college admission decisions, is one of the biggest education stories in years. Although the details of the scandal follow a familiar pattern — the powerful and wealthy using money and influence to get what they want — the high-profile cast of wrongdoers (actresses, coaches, CEOs) makes it far more salacious, if not nauseating.

      The fact that wealthy families have the upper hand when it comes to college admissions is not news to anyone, especially poor people. But the audacity of this scandal is a distasteful reminder of just how unfair postsecondary education has become in the United States. For less affluent families or first-generation college-goers, the admissions process alone can seem like an overwhelming gauntlet of decision making and paperwork. Add to that the competition with wealthier parents who can provide their kids with test prep, counselors, and resume-enhancing life experiences, and the process can become soul crushing. And the worries don’t stop when the acceptance letter arrives — because then it is time to start worrying about tuition, living expenses, and how to make the most of the experience.

      The parents involved in this scandal bought into a mythology that many elite colleges have worked hard to create. The idea that one school is so special, so rarefied, that the mere act of attending can set its students up for a happy and successful life is not an education-based strategy; it’s a marketing plan. Yes, elite networks can open doors and lower some of the barriers to entry that exist in the professional world, but this scandal is based on the false idea that the institutions themselves make a student happy and success-ful. I would argue instead that the true value of a postsecondary education ultimately depends on the student. It has been my experience that a hard-working, scrappy student who seeks out opportunities and mentors and actively builds a network can go pretty far in this world. One of the saddest aspects of this sordid story is that the adults involved didn’t have more faith in the students. Did it ever occur to them that these kids could get into a great school that was the right place for them on their own merit? Clearly not. These parents had their eyes on a completely different prize. They saw their children’s post-secondary education as a vehicle for enhancing their own social standing….

      The release of Trump’s fiscal year 2020 education budget was small peanuts after the news of the scandal broke. By proposing to cut overall spending by $7.1 billion while main-taining level funding for the grant programs with the strongest advocacy base (Title I, special education, and English language acquisition), the administration has done the political equivalent of stepping on all the flowers in the garden except the perennial favorites….

      For example, the $2.1-billion grant program that supports teacher training and development would be eliminated and replaced with a "test" program that would support the use of professional development vouchers. Putting aside the fact that the new program is only funded at $200 million (a $1.9-billion cut), do we really want to use teacher training as the proving ground for a test program that has no research base whatsoever? There is no doubt room for improvement when it comes to professional development, but when organizations like Learning Forward (whose sole focus is to support the ongoing development of teachers) express deep concerns about this plan, you have to wonder what (if any) logic is driving the administration’s stated goal of “elevating the teaching profession through innovation.”

      Higher education also took a hit in this budget. The administration once again seeks to eliminate the Public Service Loan Forgiveness program, which allows individuals who work in government or the nonprofit sector to be relieved of their student loan debt. The budget also cuts the Federal Work-Study program by a little more than half and takes away $2 billion in reserve funds for Pell Grants. These suggested cuts, which hit at the heart of federal student aid programs, come just as Congress begins the reauthorization process for the Higher Education Act. I have to believe the lingering stench of the Varsity Blues scandal will ultimately help the Democratic leaders in Congress who are pushing for a budget that actually helps students afford college….

      …Using the power of the bully pulpit, Secretary of Education Betsy DeVos had an opportunity to bring together some of the factions that fought so fiercely during the Obama years, but from the beginning it was clear she was more ideologue than diplomat….

Toward Equality of Educational Opportunity: What’s Most Promising?

[These excerpts are from an article by Arthur E. Wise in the May 2019 issue of Phi Delta Kappan.]

      …In the mid-1970s, I became concerned that advocates pushing for higher standards and tougher accountability were hijacking the movement to promote equity in school funding. The use of achievement testing was on the rise, and some saw these tests as a way to push schools to ensure that students of color and poor students achieved minimum levels of academic competency. To my mind, though, increased testing seemed likely to have a negative effect on teaching and learning in general, without doing much to provide the neediest students with high-quality instruction. Meanwhile, the flurry of activity surrounding standards, accountability; and testing would divert attention from funding inequity….

      Within a few years, many of us became convinced not only that this strategy would not work but that it was pushing education toward much greater centralization and bureaucratization….The trend began at the state level, as policy makers seized upon low-cost strategies based on practices from the business world, such as management-by-objectives, operations analysis, and other kinds of “scientific management” Soon these ideas morphed into their educational equivalents: mastery learning, behavioral objectives, minimum competency testing, and more….

      Of course, the enactment of the No Child Left Behind Act (2001) dramatically ratcheted up this trend to a new level, demanding even more standardized testing along with measures of Adequate Yearly Progress, remedies for low-performing schools, and a top-down compliance-driven approach to management. In schools serving low-performing students, the strategy has bordered on obsession, with preparation for reading and math tests crowding out other subject areas. Even at schools that serve high-performing students, the pressure to raise test scores has led administrators to narrow the curriculum and treat teachers as instruments of the bureaucracy.

      Failure should have been anticipated. Absent from the strategy was any new approach to teaching and learning, except for the unproven assumption that “if you test it, they will learn"….Perhaps the Every Student Succeeds Act of 2015, which rolls back much of the federal government's role in regulating schools, signals the beginning of the end of this movement. Still, though, it is important to acknowledge that many advocates thought that standards, testing, and accountability would lead to more equitable student outcomes. Though it has been a largely ineffective reform strategy and, in many ways, a destructive one, it is one of the three main strategies in recent decades intended to produce greater equity….

Equity in Anxious Times

[These excerpts are from an editorial by Rafael Heller in the May 2019 issue of Phi Delta Kappan.]

      As Maria Ferguson notes in this month's Washington View column, Operation Varsity Blues — the wide-ranging federal investigation into cheating and bribery in elite college admissions — already ranks as “one of the biggest education stories in years.” Since March, when the news broke, pundits have issued a steady stream of angry op-eds denouncing not just the 50 celebrities and CEOs indicted for sleazing their kids into schools like Yale and Georgetown, but also the many other (perfectly legal) ways in which well-to-do parents secure coveted spots at selective colleges for their children: making big donations, taking advantage of “legacy” admissions, hiring private college counselors, paying for test-prep services, and so on.

      …Few topics have received more attention, in these pages, than the inequitable distribution of educational resources and opportunities. Decade after decade, researchers have found that the more affluent the students, the more likely they are to study with the most experienced teachers, go to the schools with the nicest facilities, have access to the newest equipment, and enjoy many other advantages.

      Nor, for that matter, should any of this come as a surprise to the general public. For instance, every point that has been argued in response to the Varsity Blues scandal has already been detailed in best sellers….Anybody who thought rich and poor kids were competing on an even playing field simply hasn’t been paying attention.

      They sure are paying attention now, though. In part, as Ferguson points out, that's due to the celebrities involved in the Varsity Blues scandal and the sheer audacity of the fraud they appear to have committed. No doubt, though, much of it also has to do with the heightened sense of economic anxiety and resentment that has bubbled up….For many people, stories about inequality hit an awfully raw nerve right now.

Uniformity of the Universe

[This excerpt is from the fifth lecture in The Theory of Everything by Stephen W. Hawking.]

      …Nevertheless, it leaves a number of important questions unanswered. First, why was the early universe so hot? Second, why is the universe so uniform on a large scale—why does it look the same at all points of space and in all directions?

      Third, why did the universe start out with so nearly the critical rate of expansion to just avoid recollapse? If the rate of expansion one second after the big bang had been smaller by even one part in a hundred thousand million million, the universe would have recollapsed before it ever reached its present size. On the other hand, if the expansion rate at one second had been larger by the same amount, the universe would have expanded so much that it would be effectively empty now.

      Fourth, despite the fact that the universe is so uniform and homogenous on a large scale, it contains local lumps such as stars and galaxies. These are thought to have developed from small differences in the density of the early universe from one region to another. What was the origin of these density fluctuations?

      The general theory of relativity, on its own, cannot explain these features or answer these questions. This is because it predicts that the universe started off with infinite density at the big bang singularity. At the singularity, general relativity and all other physical laws would break down. One cannot predict what would come out of the singularity….

Heavenly Bodies

[This excerpt is from the first lecture in The Theory of Everything by Stephen W. Hawking.]

      Ptolemy’s model provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky. But in order to predict these positions correctly, Ptolemy had to make an assumption that the moon followed a path that sometimes brought it twice as close to the Earth as at other times. And that meant that the moon had sometimes to appear twice as big as it usually does. Ptolemy was aware of this flaw but nevertheless his model was generally, although not universally, accepted. It was adopted by the Christian church as the picture of the universe that was in accordance with Scripture. It had the great advantage that it left lots of room outside the sphere of fixed stars for heaven and hell.

      A much simpler model, however, was proposed in 1514 by a Polish priest, Nicholas Copernicus. At first, for fear of being accused of heresy, Copernicus published his model anonymously. His idea was that the sun was stationary at the center and that the Earth and the planets moved in circular orbits around the sun. Sadly for Copernicus, nearly a century passed before this idea was to be taken seriously. Then two astronomers—the German, Johannes Kepler, and the Italian, Galileo Galilei—started publicly to support the Copernican theory, despite the fact that the orbits it predicted did not quite match the ones observed. The death of the Aristotelian-Ptolemaic theory came in 1609. In that year Galileo started observing the night sky with a telescope, which had just been invented.

      When he looked at the planet Jupiter, Galileo found that it was accompanied by several small satellites, or moons, which orbited around it. This implied that everything did not have to orbit directly around the Earth as Aristotle and Ptolemy had thought. It was, of course, still possible to believe that the Earth was stationary at the center of the universe, but that the moons of Jupiter moved on extremely complicated paths around the Earth, giving the appearance that they orbited Jupiter. However, Copernicus’s theory was much simpler.

      At the same time, Kepler had modified Copernicus’s theory, suggesting that the planets moved not in circles, but in ellipses. The predictions now finally matched the observations. As far as Kepler was concerned, elliptical orbits were merely an ad hoc hypothesis—and a rather repugnant one at that because ellipses were clearly less perfect than circles. Having discovered, almost by accident, that elliptical orbits fitted the observations well, he could not reconcile with his idea that the planets were made to orbit the sun by magnetic forces.

      An explanation was provided only much later, in 1687, when Newton published his Principia Mathematica Naturalis Causae. This was probably the most important single work ever published in the physical sciences. In it, Newton not only put forward a theory of how bodies moved in space and time, but he also developed the mathematics needed to analyze those motions. In addition, Newton postulated a law of universal gravitation. This said that each body in the universe was attracted toward every other body by a force which was stronger the more massive the bodies and the closer they were to each other. It was the same force which caused objects to fall to the ground. The story that Newton was hit on the head by an apple is almost certainly apocryphal. All Newton himself ever said was that the idea of gravity came to him as he sat in a contemplative mood, and was occasioned by the fall of an apple.

They Persisted

[These excerpts are from an article by Sara Talpos in the 17 May 2019 issue of Science.]

      …The concerned citizens uncovered evidence that the tannery had contaminated large swaths of land and water with chemicals known as a per- and polyfluoroalkyl substances (PFASs), which researchers have linked to an array of human health problems. More than 4000 such compounds exist, and they are widely used in products such as fire-fighting foams, nonstick coatings, carpeting, food packaging, and even dental floss. The tannery used two PFASs by the ton to waterproof shoe leather….

      …Around the country, evidence of PFAS contamination has anxious residents demanding to know how exposure could affect their health. Regulators are struggling to balance cost and risk as they set safety limits. And companies, fire departments, water utilities, and the U.S. military are facing cleanup and liability costs that could total tens of billions of dollars or more….

      At the heart of the PFAS controversy is the carbon-fluorine bond, among the strongest of all chemical bonds. Enzymes can’t break it. Sunlight can't break it. Water can’t break it. That durability explains the commercial appeal of PFASs, but it makes them problematic pollutants. They’ve been dubbed “forever chemicals” because they don’t degrade naturally. And because the molecules have a water-soluble head, water and airborne droplets can carry them for long distances.

      The U.S. chemists who discovered how to synthesize PFASs in the 1930s, however, were beguiled by their advantages. Use of the chemicals in the United States began to expand rapidly during the 1950s, when the Minnesota Mining and Manufacturing Company, a Saint Paul-based firm now called 3M, began to sell two compounds: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). PFOA became the basis for Teflon, the ubiquitous nonstick cookware coating manufactured by DuPont. PFOS became a key ingredient in firefighting foams used at airports and military bases and in the popular Scotchgard protestant, which enabled fabrics and other materials to resist water and oils….

      Even as sales of PFOA and PFOS boomed, however, 3M and DuPont researchers were amassing evidence that the chemicals accumulated in people and other animals and could have toxic effects. Much of that evidence became public only because of a lawsuit. In 1980, DuPont purchased farmland in West Virginia and began to dump waste laced with PFOA there. Cattle that grazed nearby began to die, and in 1999 a local family sued the company. The proceeding forced DuPont to hand over internal files….In 2001, DuPont paid an undisclosed sum to settle the case, and EPA fined the company in 2005 for violating rules for toxic waste. Under pressure from EPA, U.S. manufacturers agreed in 2006 to phase out production of PFOA by 2015. (They ended PFOS production in 2002.) Often, the two chemicals were replaced by related PFASs that manufacturers have asserted are safer and break down faster….

      …In 2011 and 2012, three independent epidemiologists who analyzed the data issued reports indicating a probable link between PFAS exposure and six conditions: high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, and pregnancy-induced high blood pressure….

      Meanwhile, other researchers were finding that almost all people living in the United States carry detectable levels of PFASs in their blood (although levels of PFOA and PFOS have declined since they were phased out). And the more researchers looked for PFAS contamination around industrial sites, airports, and military bases, the more they found….

      After the CDC report became public, however, the Trump administration—under growing pressure from Congress and state officials—promised to take action. And in February, EPA released a plan that calls for formally setting regulatory limits for PFOA and PFOS and for launching a nationwide program to monitor PFASs in water systems. The agency said it will beef up research into detection and cleanup methods, consider requiring companies to report PEAS releases, and even consider banning certain compounds.

      EPA also is planning to intensively examine about 125 of the thousands of newer, less studied PFASs, in collaboration with the National Toxicology Program. One goal is to test the assumption that the newer compounds are safer because they have shorter lives….

Uncovering the Hidden Curriculum

[These excerpts are from an article by Janani Hariharan in the 17 May 2019 issue of Science.]

      …I did not know what was expected of me or how the academic system operated. I was confused and desperate for help.

      “You’re too nice!” the professor said. “You’re very quick to agree with everyone, and you never stand up for yourself.” I was taken aback. Was I allowed to disagree with a professor? All my previous training had taught me otherwise. Clearly there was a whole set of rules I didn't know I wondered whether I ever would….

      …I struggled with assignments that tested my thinking and presentation skills instead of asking me to memorize and regurgitate information. The approach to grading was peculiar and confusing….

      …For me, things started to take a turn for the better when I realized I could reach out for help….

      …As I answered their questions I suddenly realized that, even though I was still learning, I had knowledge to share that could help others navigate the hidden curriculum….

Two Threats to U.S. Science

[These excerpts are from an editorial by Bruce Alberts and Venkatesh Narayanamurti in the 17 May 2019 issue of Science.]

      …The cycle of success that catapulted the United States to a global leadership position in science and technology has long been fueled by its many research universities. These institutions create the new fundamental knowledge in science and engineering on which all else depends, and they also train the large numbers of outstanding young people required to produce the next generation of professors, technologists, and entrepreneurs. U.S. universities have attracted great young scientists and engineers from all over the world, many of whom choose to remain in the country, strengthening our institutions and enterprises. Two critical features of this system are now threatened: the support of young people and their unique potential to take risks and explore promising new ideas; and a merit-based selection of scientists and engineers to populate academia and industry, view-ing everyone as equal, regardless of the nation in which they were born.

      The current grant opportunities for starting a new independent research career in academia have not only become increasingly unavailable to young scientists and engineers, but are also disastrously risk-averse. At the NIH, the proportion of all grant funds awarded to scientists under the age of 36 fell from 5.6% in 1980 to 1.5% in 2017. One might ask the rhetorical question: How successful would Silicon Valley be if nearly 99% of all investments were awarded to scientists and engineers age 36 years or older, along with a strong bias toward funding only safe, nonrisky projects? Similarly, at the U.S. Department of Energy and its National Laboratories, high-risk, high-reward research and development has been severely limited by extreme volatility in research funding and by very limited discretionary funding at the laboratory level.

      Another major concern stems from a new distressing and dangerous public dialogue, encouraged by some political leaders, that unjustly disparages the many people in the United States who were born elsewhere. This strikingly un-American attitude, along with the new visa policies that it has generated, is discouraging migration to the United States of the young talent in science and engineering from other nations instrumental to the nation’s success….Nearly half of current doctoral students in science, technology, engineering, and mathematics (STEM) fields are from abroad, and the United States needs to make it easier, not harder, for them to stay and contribute to the cycle of success.

      U.S. leadership must focus on stimulating innovation by awarding an equal number of grants to those new investigators proposing risky new research ideas and those proposing to extend the research that they did during their training period, while also funding them at a younger age. At the same time, it is imperative that the United States reconsider its visa and immigration policies, making it much easier for foreign students who receive a graduate degree in a STEM discipline from a U.S. university to receive a green card, while stipulating that each employment-based visa automatically cover a worker’s spouse and children….

Turning off the Emotion Pump

[These excerpts are from an article by Wade Roush in the May 2019 issue of Scientific American.]

      …Facebook watches to learn what pleases you and what angers you, and it uses that information to auction ads to companies that want to reach consumers with your specific profile. It also watches what everyone else likes, then shows you more of whatever is most engaging that day—the better to keep you scrolling, so that you’ll encounter more ads….Think of it as an emotion pump. You finish reading a post. Before you can close the app or click to another browser tab, you scroll some more, almost by reflex. In that moment, Facebook injects another post optimized to make you laugh or get you angry, and the cycle continues. Polarizing content keeps the pump constantly primed by riling users up.

      The side effects of this strategy have become plain in nations such as Myanmar, the Philippines and the U.S., where misinformation shared on Facebook has fueled division and social unrest….Russian-sponsored Facebook ads and posts swayed the outcome of the 2016 presidential election. Nobody at Facebook anticipated these effects. But they can’t be swept under the rug—and they can’t be solved through minor algorithmic adjustments, because this is Facebook. The emotion pump is at the core of its business model.

Climate-Friendly Capitalism

[These excerpts are from an editorial by the editors in the May 2019 issue of Scientific American.]

      …Recently more and more of these resolutions have pushed companies to act on climate change and reduce greenhouse gas emissions. Two years ago, for instance, investor proposals forced Shell to sell off carbon-rich oil sands assets. Investors also made the company tie 10 percent of executive bonus pay to success in cutting emissions. And earlier this year BP, bowing to investor pressure, agreed to align future capital spending with the targets of the 2015 Paris climate accord, reducing emissions enough to keep global temperature rise below two degrees Celsius. That could mean cuts as high as 50 percent, depending on the country.

      This year and going forward, investors should exert more of this leverage on these and other companies. That is because politicians, especially in the U.S., have abjectly failed to address the threats that climate change poses to health, national security and the environment. President Donald Trump has repeatedly said he does not see climate change as a problem, despite strong and steadily growing scientific evidence from the world’s researchers—and his own government agencies. This year the White House took steps to create a panel, chaired by someone who believes mounting carbon dioxide is good for the planet, to attack this overwhelming scientific consensus. On a local level, the state of Washington recently voted down a tax on carbon emissions.

      The businesses that generate large amounts of greenhouse gases, in contrast, have proved willing to change their ways when investors insist on it. Of the more than 600 largest publicly traded companies in the U.S., 64 percent have now made commitments to reduce emissions….

      Companies’ desire to avoid embarrassing proxy-season showdowns has given rise to another investor force—a shareholder network called Climate Action 100+, whose members have $32 billion in assets under management and try to push corporate changes outside of these yearly meetings. One success earlier this year: international mining giant Glencore said it will not grow its coal-mining business any larger and will develop targets for emissions reductions. Climate Action 100+ is also pressing nonenergy businesseS that generate a lot of emissions, such as steel manufacturers, to line up behind science-based reduction goals.

      The motive of these investment funds is not unfettered altruism. While they hold oil company stock, they also invest in real estate along coastlines threatened by rising seas, in health care firms whose costs will increase, and in dozens of other sectors that stand to take a substantial hit if climate change is not brought under control. So they have to take a long-term and global view….

The Trillion-Gallon Problem

[These excerpts are from an article by Shanti Menon in the Spring 2019 issue of Environmental Defense Fund’s Solutions.]

      …Scientists linked Oklahoma’s sudden jump in earthquake activity to pressure from wastewater injected into underground disposal wells by the oil and gas industry. The state limited those injections, but the volume of wastewater has been rising rapidly nationwide. The industry now produces a trillion gallons of it every year — enough to fill more than a million Olympic swimming pools….

      This year, the EPA and water-stressed states such as New Mexico, Oklahoma and Texas could open the door to all kinds of wastewater disposal and reuse, including expanding the discharge of treated wastewater into rivers and streams and reusing treated wastewater on lawns, golf courses, ranches and farms. Some have even considered using it to replenish drinking water supplies.

      There’s one mega-problem: Nobody really knows what’s in this water.

      Without an understanding of what’s in wastewater or how to clean it, risky proposals to discharge or reuse it could threaten precious groundwater, crops, livestock and people's health across the parched American West….

      In hard-rock formations such as the Permian Basin, which straddles Texas and New Mexico, oil and gas companies extract petroleum by injecting billions of gallons of water mixed with chemicals into the rock at high pressure.

      The wastewater that comes out the other side can contain more than 1,000 chemicals, including cancer-causing arsenic and benzene. Some of these occur naturally underground, others are purely industrial….

      In the 1920s, wastewater released directly onto Texas soil created the Texon Scar, a patch of blighted earth visible from space. Cleanup of the scar is still ongoing today, nearly 100 years later.

      The composition of wastewater varies from well to well. Samples are hard to get and difficult to analyze. Some of the chemicals used are industrial secrets….

      …Of the 1,200 chemicals listed to date, most are not well studied, and some have not been evaluated at all. This makes it difficult to determine when wastewater is clean enough to discharge and what impacts it might have on a farmer's fields, a rancher's cattle, fish in a river or drinking water.

      Even as the science begins to raise red flags, research is being outpaced by the rapid rise of water-intensive drilling in places like the Permian Basin. Some in the industry want to rush into wastewater reuse and discharge now seeing a window of opportunity in today’s industry-friendly EPA led by AndrewWheeler. The safeguards that regulate wastewater discharge were created decades ago, when the industry discharged relatively little. This summer, the EPA will decide if it’s time to reconsider the rules….

      For the moment, there's enough room to handle wastewater with disposal wells that are properly located, designed and monitored to avoid groundwater pollution and earthquakes. In the future, more water could be recycled on-site, and eventually, with a lot more science and strong state and federal safety standards, it could be treated and reused in ways that minimize environmental risks.

      Not everyone is willing to wait. An entrepreneurial ex-rodeo clown in VVyoming claims he can treat wastewater for crop irrigation, and is gearing up for a state-authorized test on a wheat field. In the Permian Basin, organizations eager to explore wastewater treatment and reuse have sprung up like Texas wildflowers. A recent joint paper from the EPA and the state of New Mexico renames oil field wastewater as “renewable water.”

      In this Wild West of water pushers, drought and environmental rollbacks, all options appear to be in play. But with so many unknowns, there's no way to be certain that treated wastewater is clean enough for these new purposes….

Can a Dire Ecological Warning Lead to Action?

[These excerpts are from an article by Erik Stokstad in the 10 May 2019 issue of Science.]

      After issuing a landmark report warning of a deepening planetary threat from the loss of biodiversity, a global scientific advisory group faces a new and daunting challenge: helping policymakers act to stop the decline.

      At least 1 million plant and animal species of the estimated 8 million known are now at risk of extinction, according to this week’s report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Already, environmental degradation imperils the natural systems that provide us with food, water, and livelihoods….

      Blunting the threat will require transformational economic and social change, the report concludes. And now, 7-year-old IPBES faces the question of how to best help catalyze that transformation. Some experts want the group to put a greater emphasis on working closely with policymakers….But others caution that IPBES must remain a politically neutral provider of science-based information and not strain its limited resources.

      ….human activities, especially agriculture and exploitation such as hunting, have “severely altered” 75% of Earth’s land area, helped kill about half of the world’s coral reefs, and decimated many wildlife populations. It forecasts that, at expected rates of human population growth and consumption, the trends will worsen without major changes, including the adoption of new farming practices. More fundamentally, the report says business and political leaders need to begin “steering away from the current limited paradigm of economic growth.”

      ….meaningful change often requires extensive practical follow-up work with those who make and implement government policies….

      …Politicians from coastal nations, for example, might want to know how to conserve ecosystem benefits, such as productive fisheries and mangroves that provide storm protection, while allowing for development and economic activities. Other nations might be more interested in how to manage forests so they can produce and purify water while continuing to provide fuel and timber.

      Observers say IPBES can also help national decision-makers by identifying and recommending products that might be especially relevant, such as computer models for analyzing different approaches to balancing competing needs and minimizing social conflicts. IPBES is planning to create a new task force dedicated to identifying such tools. And it already has an online catalog for sharing such resources….

      IPBES needs to be careful, however, not to prescribe specific policies….Too much detail…can make it difficult for the group’s diverse member nations to agree on and approve the reports.

      That balancing act is likely to be on display in coming years, as IPBES finishes three ongoing assessments, including a report on the various ways that people value nature, due in 2022, and another on the sustainable use of wild species such as fish and medicinal plants….

Ancient Jaw Gives Elusive Denisovans a Face

[These excerpts are from an article by Ann Gibbons in the 3 May 2019 issue of Science.]

      Thirty-nine years ago, a Buddhist monk meditating in a cave on the edge of the Tibetan Plateau found something strange: a human jawbone with giant molars. The fossil eventually found its way to scientists. Now, almost 4 decades later, a groundbreaking new way to identify human fossils based on ancient proteins shows the jaw belonged to a Denisovan, a mysterious extinct cousin of Neanderthals.

      The jawbone is the first known fossil of a Denisovan outside of Siberia’s Denisova Cave in Russia, and gives paleoanthropo-logists their first real look at the face of this lost member of the human family….

      Together, the jaw’s anatomy and the new method of analyzing ancient proteins could help researchers learn whether other mysterious fossils in Asia are Denisovan….

      The international team of researchers also reports that the jawbone is at least 160,000 years old. Its discovery pushes back the earliest known presence of humans at high altitude by about 120,000 years.

      A massive search for Denisovans has been underway ever since paleogeneticists extracted DNA from the pinkie of a girl who lived more than 50,000 years ago in Denisova Cave and found she was a new kind of human….

Pipe Dreams

[These excerpts are from an article by James Temple in the May/June 2019 issue of MIT Technology Review.]

      Severe droughts have drained rivers, reservoirs, and aquifers across vast parts of India in recent years, pushing the nation’s leaky, polluted water systems to the brink.

      More than 600 million Indians face “acute water shortages,” according to a report last simmer by NITI Aayog, a prominent government think tank. Seventy percent of the nation's water supply is contaminated, causing an estimated 200,000 deaths a year. Some 21 cities could run out of groundwater as early as next year, including Bangalore and New Delhi, the report found. Forty percent of the population, or more than 500 million people, will have “no access to drinking water” by 2030.

      India gets more water than it needs in a given year. But the vast majority of rain falls during the summer monsoon season, generally a four-month window. The country’s other major source is melting snow and glaciers from the Himalayan plateau, which feeds rivers in the north.

      Capturing and delivering the water to the right places at the right times across thousands of miles, without wasting or contaminating tremendous amounts along the way, is an enormous engineering challenge. India captures and uses only a fraction of its rainfall, allowing most of it to run off into the ocean.

      Meanwhile, farmers without efficient irrigation systems employ heavily subsidized electricity to suck up as much groundwater as possible. Agriculture is the single largest drain on India’s water supplies, using more than 80% of the water despite accounting for only around 15% of the country’s GDP….

      Climate change will surely make the problem worse. It’s uncertain what role higher temperatures have played in recent droughts, as the climate models have mainly predicted increasingly intense Indian monsoons. But the longer-term forecast is that the extremes will become more extreme, threatening more frequent flooding and longer droughts.

      Most climate studies predict that India will get more rain on average in the decades to come, though regional and seasonal patterns will vary sharply. A paper published last year in Geophysical Research Letters found that flash flooding will significantly increase in 78 of the 89 urban areas evaluated if global temperatures rise to 2 °C above preindustrial levels. The resulting catastrophes will disproportionately harm India's poor, who frequently settle along the low-lying floodplains of major cities.

      Sea-level rise threatens to deluge villages and megacities, and poison the water tables, along the subcontinent’s 7,500 kilometers (4,660 miles) of coastline between the Arabian Sea and the Bay of Bengal.

      Finally, climbing temperatures and shrinking snowfall will accelerate the melting of the Himalayan glaciers, the wellspring of major Asian waterways including the Ganges, Indus, Yangtze and Yellow rivers. In some regions, under high emissions scenarios, glaciers could shrink by as much as half by midcentury and 95% by 2100.

      Initially the increased runoff will swell rivers, raising the risks of downstream flooding but sending Indians more water. That trend is likely to shift into reverse in the second half of the century, however, shrinking the flow to around 1.9 billion people who live along those rivers. The Ganges basin alone supports 600 million Lfapeople, provides 12% of the country’s surface water, and accounts for 33% of GDP….

      Whether shoddy infrastructure or climate change is to blame for India’s water sources running dry or turning toxic won’t, in the end, much matter in the minds of the victims. And either way, India will need to grapple with present-day disasters and fortify infrastructure for wane dangers to come—all with fewer resources than rich nations and without derailing its economic growth….

How to Cool an Ocean

[These excerpts are from an article by Holly Jean Buck in the May/June 2019 issue of MIT Technology Review.]

      Coral reefs smell of rotting flesh as they bleach. The riot of colors—yellow, violet, cerulean—fades to ghostly white as the corals’ flesh goes translucent and falls off, leaving their skeletons underneath fuzzy with cobweb-like algae.

      Corals live in symbiosis with a type of algae. During the day, the algae photosynthesize and pass food to the coral host. During the night, the coral polyps extend their tentacles and catch passing food. Just 1°C of ocean warming can break down this coral-algae relationship. The stressed corals expel the algae, and after repeated or prolonged episodes of such bleaching, they can die from heat stress, starve without the algae feeding them, or become more susceptible to disease.

      Australia’s Great Barrier Reef—actually a 2,300-kilometer (1,400-mile) system made up of nearly 3,000 separate reefs—has suffered severe bleaching in the past few years….

      Coral reefs are not just about colorful fish and exotic species. Reefs protect coasts from storms; without them, waves reaching some Pacific islands would be twice as tall. Over 500 million people depend on reef ecosystems for food and livelihoods. Even if the temperature increase eventually stabilizes at 1.5 °C a century or two from now, it’s not known how well coral reef ecosystems will survive a temporary over-shoot to higher temperatures….

      Arctic ecosystems, mountain glaciers, and the redwood forests in California are also at high risk from even small changes in global mean temperature. So are species that can’t move quickly and find another suitable niche….

      Besides upsetting ecosystems, ocean warming will, of course, raise sea levels. They are already 13 to 20 centimeters (5 to 8 inches) higher than in 1900. In the 20th century, most of this rise came from ocean waters expanding as they got warmer, but now the effects of melting glaciers and ice sheets have far overtaken thermal expansion. The rise produced by melting glaciers is projected to be staggering—on the order of meters per century.

      But what if we could engineer specific glaciers to keep them from melting? John Moore, a glaciologist and leader of China’s geoengineering research program, has recently been looking into this, and he wrote a comment with colleagues in Nature that outlines a few ways to do it.

      One example involves two Antarctic glaciers scientists have a nervous eye on: Pine Island and Thwaites. Warm ocean water comes in underneath them. Conventional wisdom says this is unstoppable and irreversible, because of the bedrock slope and geometry. But Moore suggests that building artificial islands in front of the glaciers could buttress them, pinning down the ice and holding it back the way natural rocks and islands do.

      Another technique would be to extract water from below the glaciers to keep them from sliding off into the ocean. Glaciers sit on subglacial streams, or thin layers of water, but drying these streams could slow their slide into the sea….

The Threat to the World’s Breadbasket

[This excerpt is from an article by Adam Piore in the May/June 2019 issue of MIT Technology Review.]

      By 2050, the world’s population is expected to grow to 9.7 billion. As living standards and diets also improve around the world, food production will have to increase by SO% at a time when climate change will help make both sub-Saharan African and. East Asia unable to meet their own needs without imports. Already US corn and soybeans account for 17% of the world’s caloric output. The UN Food and Agriculture Organization projects that American exports of corn must almost triple by 2050 to meet the shortfall, while US soy exports would have to rise by more than 50%. All this extra food has to be grown without using significantly more land. That means it's going to be all about yield—the productivity of the crop.

Already Hot and Getting Hotter

[These excerpts are from an article by Lauren Zanolli in the May/June 2019 issue of MIT Technology Review.]

      …Since the spring of 2018, Mexico’s Caribbean coast and the shorelines of 19 other countries in the region have been inundated with unprecedented amounts of Sargassum seaweed. Tourists expecting pristine white beaches have instead been confronted with endless piles of slimy, decaying vegetation. While it’s normal for the brown macroalgae to appear on Caribbean shorelines in smaller amounts, outlier blooms have been increasing in size and regularity over the past 10 years. The one that occurred last year is believed to be the worst ever in the region. Now efforts are mounting not just to contain the ecological crisis but to capitalize on it.

      Usually Sargassum arrives in the Caribbean from its namesake sea in the eastern Atlantic. But researchers believe the 2018 influx came from a new source: the equatorial waters between Brazil and West Africa, where pesticide and fertilizer runoff from the Amazon and Congo Rivers fed the algae bloom. This bloom was amplified by climate change....rising ocean temperatures help the seaweed proliferate faster. Deforestation in the Amazon rain farest also feeds the bloom—not only does it increase the pesticide and fee tilizerninoff, but it is itself a massive contributor to climate change….

      In ordinary conditions, Sargassum is a normal, even healthy, part of the ocean. But in vast quantities, the seaweed brings a litany of harms to ceastal ecosystems. Mats of it block much-needed sunlight from coral reefs, causing disease or death. As the seaweed dies and decays, baceria suck up oxygen in the water ile nitrogen, phosphorus, and other nutrients are released in massive quantities. If the seaweed is left to rot on land, as it is on Mexico’s beaches, the samealutrients threaten to leach into groundwater. In the Yucatan Peninsula, where the only source of fresh water is a unique regional network of underground rivers, water contamination is a serious worry. And while seaweed can draw carbon dioxide from the atmo-sphere, just as trees do, it’s beneficial for the environment only if the seaweed is harvested and processed, and the resulting CO2 is stored away permanently….

India’s Dilemma

[These excerpts are from an article by James Temple in the May/June 2019 issue of MIT Technology Review.]

      …India has recently completed or approved dozens of giant solar and wind projects, nearly doubling its renewables capacity since 2015. For the last two years, it was the fastest builder of solar projects on the planet after China. All told, the country has around 75 gigawatts of solar, wind, and other renewable sources installed—and more than 45 gigawatts in the pipeline.

      In 2015, government officials announced plans to more than quadruple renewables capacity, setting a target of 175 gigawatts by 2022. Later that year, under the Paris climate accords, India committed to produce 40% of its electricity from clean sources and cut emissions intensity (the level of carbon dioxide produced per unit of GDP) to at least 33% below 2005 levels by 2030.

      India is now a shining case study in how rapidly generation of renewable power can expand with government investment and support, even in a deeply poor country. But it also underscores the fact that adding clean energy and cutting climate emissions aren’t the same thing.

      For India to achieve the latter, clean energy would need to replace—not simply augment—coal, which currently generates nearly 55% of the nation’s electricity. And that's not happening anytime soon in one of the world’s fastest growing and fastest urbanizing economies.

      India’s GDP could more than quintuple by 2040, more than doubling its energy demand, according to the International Energy Agency. That would represent roughly a quarter of the total global increase over that period.Air-conditioning units alone could increase by 15-fold, as citizens become better off and cities grow hotter….

      Estimates vary widely, but the IEA expects that carbon emissions from India’s power sector will rise 80% through 2040 even with the renewable generating plants currently planned. By then India could overtake the US as the world’s second largest emitter, undermining efforts to curb global warming. If India can’t pull off the necessary reductions, even with its substantial policies and investments, it means that wealthy nations will need to step up their efforts even more….

      India has shown that a developing nation can rapidly add clean energy, at costs below those associated with coal plants, while still expanding its economy and creating jobs….

      …It’s still likely to take decades before the nation’s renewables start to replace coal and bring down emissions, given how fast energy needs are growing and how hard it is to integrate intermittent sources like wind and solar….

      Last spring, following a three-year, $2.5 billion government-funded effort to link transmission lines to the most remote parts of the country, Modi trumpeted that “every single village of India now has access to electricity?”

      But the government set a low bar, ticking the box so long as 10% of households in a village, and institutions like schools and hospitals, were connected. That means as many as 90% of rural households in many villages still aren’t wired, and even those that are may get power only a few hours a day. At least tens of millions of Indians still lack electricity.

      Fixing all this is likely to require far more funding and a broad regulatory overhaul, including penalties for utilities that fail to provide power and reforms that move prices closer to market rates. But the latter is an extremely unpopular notion in India, where the belief that the state should deliver cheap power is deeply held, dating back to the earliest promises of independence….

      …The UN’s climate-change body has concluded that the world needs to cut carbon dioxide emissions 45% from 2010 levels by 2030, and eliminate them entirely by midcentury, to have a decent chance of preventing 1.5 °C of warming. India is the world's fourth largest emitter, contributing 7% of emissions, behind China (27%), the US (15%), and the European Union (10%), according to the Global Carbon Project.

      But it’s fundamentally unfair to ask the country to cap its climate pollution and stunt its growth now, given that richer countries have pumped out far more carbon dioxide to get to where they are today. They’ve enjoyed decades of accumulating economic growth thanks largely to cheap fossil fuels.

      India’s per capita energy consumption is around one-tenth of America's—and even if it doubles by 2030, it will be only half what China’s was in 2015….

      …Arguably, wealthier countries should also help poorer ones reduce emissions, whether that’s by providing low-interest capital or subsidized technology, or by developing cheaper clean-energy solutions. If they don't want to do it because it’s the right thing to do, then they should do it for the self-interested reason: climate change doesn’t recognize borders.

What Would You Pay to Save the World?

[These excerpts are from an article by David Rotman in the May/June 2019 issue of MIT Technology Review.]

      In contrast to the existential angst currently in fashion around climate change, there’s a cold-eyed calculation that its advocates, mostly economists, like to call the most important number you’ve never heard of.

      It’s the social cost of carbon. It reflects the global damage of emitting one ton of carbon dioxide into the sky, accounting for its impact in the form of warming temperatures and rising sea levels. Economists, who have squabbled over the right number for a decade, see it as a powerful policy tool that could bring rationality to climate decisions. It’s what we should be willing to pay to avoid emitting that one more ton of carbon.

      For most of us, it's a way to grasp how much our carbon emissions will affect the world's health, agriculture, and economy for the next several hundred years….

      Common estimates of the social cost Lof that ton are $40 to $50. The cost of the fuel for the journey in an average car is currently around $225. In other words, you’d pay roughly 20% more to take the social cost of the trip into account.

      The number is contentious, however. A US federal working group in 2016, convened by President Barack Obama, calculated it at around $40, while the Trump administration has recently put it at $1 to $7. Some academic researchers cite numbers as high as $400 or more.

      Why so wide a range? It depends on how you value future damages. And there are uncertainties over how the climate will respond to emissions. But another reason is that we actually have very little insight into just how climate change will affect us over time. Yes, we know there’ll be fiercer storms and deadly wildfires, heat waves, droughts, and floods. We know the glaciers are melting rapidly and fragile ocean ecosystems are being destroyed. But what does that mean for the livelihood or life expectancy of someone in Ames, Iowa, or Bangalore, India, or Chelyabinsk, Russia?

      For the first time, vast amounts of data on the economic and social effects of climate change are becoming available, and so is the computational power to make sense of it. Taking this opportunity to compute a precise social cost of carbon could help us decide how much to invest and which problems to tackle first….

      Over the last several years, economists, data scientists, and climate scientists have worked together to create far more detailed and localized maps of impacts by examining how temperatures, sea levels, and precipitation patterns have historically affected things like mortality, crop yields, violence, and labor productivity. This data can then be plugged into increasingly sophisticated climate models to see what happens as the planet continues to warm.

      The wealth of high-resolution data makes a far more precise number possible—at least in theory….

      So far, the researchers have found that climate change will kill far more people than once thought….It found that the social cost of carbon due to increased mortality alone is $30, nearly as high as the Obama administration's estimate for the social cost of all climate impacts. An additional 9.1 million people will die every year by 2100, the group estimates, if climate change is left unchecked (assuming La global population of 12.7 billion people)….

      If climate change is left to run unchecked through the end of the century, the southern and southwestern US will be devastated by rising rates of mortality and crop failure. Labor productivity will slow, and energy costs (especially due to air-conditioning) will rise. In contrast, the northwestern and parts of the northeastern US will benefit….

      India is the big loser. Not only does it have a fast-growing economy that will be slowed, but it’s already a hot country that will suffer greatly from getting even hotter….

      Estimating the global social cost of carbon also raises a vexing question: How do you put a value on future damages? We should invest now to help our children and grandchildren avoid suffering, but how much? This is hotly and often angrily debated among economists….

      There’s an ethical dimension to these calculations. Wealthy countries whose prosperity has been built on fossil fuels have an obligation to help poorer countries. The climate winners can’t abandon the losers. Likewise, we owe future generations more than just financial considerations. What’s the value of a world free from the threat of catastrophic climate events—one with healthy and thriving natural ecosystems?

      …Enter the Green New Deal (GND). It's the sweeping proposal issued earlier this year by Representative Alexandria Ocasio-Cortez and other US progressives to address everything from climate change to inequality. It cites the dangers of temperature increases beyond the UN goal of 1.5 °C and makes a long list of recommendations. Energy experts immediately began to bicker over its details: Is achieving 100% renewables in the next 12 years really feasible? (Probably not.) Should it include nuclear power, which many climate activists now argue is essential for reducing emissions?

      In reality, the GND has little to say about actual policies and there’s barely a hint of how it will attack its grand challenges, from providing a secure retirement for all to fostering family farms to ensuring access to nature. But that’s not the point. The GND is a cry of outrage against what it calls “the twin crises of climate change and worsening income inequality.” It’s a political attempt to make climate change part of the wider discussion about social justice. And, at least from the perspective of climate policy, it’s right in arguing that we can’t tackle global warming without considering broader social and economic issues….

      Nevertheless, the investments will take decades to pay for themselves. Renewables and new clean technologies may lead to a boom in manufacturing and a robust economy, but the Green New Deal is wrong to paper over the financial sacrifices we’ll need to make in the near term.

      That is why climate remedies are such a hard sell. We need a global policy—but, as we’re always reminded, all politics is local. Adding 20% to the cost of that San Francisco-Chicago trip might not seem like much, but try to convince a truck driver in a poor county in Florida that raising the price of fuel is wise economic policy. A much smaller increase sparked the gilets jaunes riots in France last winter. That is the dilemma, both political and ethical, that we all face with climate change.

The “Mind-boggling” Problem of Keeping New York Dry

[These excerpts are from an article by Courtney Humphries in the May/June 2019 issue of MIT Technology Review.]

      …temperatures in the city could be hotter on average by 4 to 6 °F (about 2 to 3 °C), with several heat waves per summer. Sea levels could rise 11 to 21 inches (28 to 53 centimeters) by the 2050s and up to six feet (1.8 meters) by 2100—doubling the size and population of the 100-year-flood zone, the area that has a 1% annual chance of flooding. The borough with the most land affected by all this will be Queens….

      Climate resilience is expensive and onerous. Seven projects in the region got federal funding in a post-Sandy design competition called Rebuild by Design, but several years later, not one has broken ground. Last fall, the city abruptly changed plans for the first phase of the “Big U,” a project that would create and connect 10 miles of parks, barriers, and flood walls around the low-lying area from East 57th Street down to the Battery and up West 42nd Street. The city eschewed an innovative approach that would allow a newly redesigned East River Park to partially flood during storms, deciding to spend more money to raise the park 8 to 10 feet, adding fill that may cover natural habitats….

Democracy Endangered

[This excerpt is from an article by Susan Silbey in the May/June 2019 issue of MIT News.]

      Today, more people than ever before in human history enjoy the rights and privileges of citizenship—the ability to participate in self-governance.

      Yet the internet, search platforms, and social media—the very same technologies that join people across the globe in more widespread connections—also represent the most significant and disruptive threats to our democracies since the founding of the modern democratic state.

      We live in a world where time and space, people and things, are organized in a radically new way. Vast temporal, spatial, and cultural distances are bridged; social organizations based on similarity and proximity have been transformed into connections among very different and very distant people. The quantity and pace of social interactions have increased geometrically. The everyday lives of most people in most social classes all over the globe are filled with more encounters, of shorter duration, and over greater distances than ever before. This is life on the internet.

      Amid this escalating, energetic circulation of information and comment, threats to democratic citizenship take root.

      We do not simply use the internet—to shop, find information, or keep track of appointments and friends. With every click, search, and view, we provide the information for algorithms to analyze and platform companies to sell. We supply the inputs—the raw materials of what is now a world of constant digitized surveillance. We, the users, are ourselves used.

      New and largely uncontested forms of power have been concentrated in a handful of firms that extract personal information in unexpected and often hidden ways. Techniques for monitoring, personalization, and customization are contractually permitted and regularly improved. Layered on top of that are continuous experimentation, commodification, and control.

      The internet now freely distributes more information than has ever circulated in human history. At the same time, as the circulation of knowledge advances, the threats to expertise and truth escalate, challenging democratic norms and the centuries-long evolution of democratic citizenship.

      How did this happen?

      First, the inventors of the internet overlooked the essential role of context in shaping the uses and consequences of technology. A tool made for physicists to exchange data on a platform built for the military was given to the world. Designed for a cohesive and highly disciplined community, it was distributed to a world ungoverned by shared norms of participation.

      A second mistake was generalizing from personal experience: “This is such a good technology for us, it will be good for everyone.” By seeing themselves as everyman, the inventors ignored human variation. They forgot to user-test with diverse populations.

      Finally, the inventors demonstrated canonical groupthink: talking and listening to a narrow set of like-minded people, excluding unfamiliar, perhaps even critical, perspectives.

      So what do we do now…?

Rock Lobster

[This excerpt is from an article by Jennifer Chu in the May/June 2019 issue of MIT News.]

      Flip a lobster on its back, and you'll see that the underside of its tail is lined with a translucent membrane that appears more vulnerable than the armor-like carapace shielding the rest of the crustacean.

      But MIT engineers have found that this soft membrane is surprisingly tough, with a plywood-like microscopic structure that prevents scrapes and cuts as the animal scuttles across the rocky seafloor.

      The membrane is a natural hydrogel, composed of 90% water, so it's flexible enough to allow the lobster to whip its tail back and forth. (Chitin, a fibrous material found in many shells and exoskeletons, makes up most of the rest.) But the membrane stiffens dramatically when stretched, making it difficult for a predator to chew through the tail or pull it apart.

      The team discovered that the lobster membrane is the toughest of all natural hydrogels, including collagen, animal skins, and rubber. It's also about as strong as industrial rubber composites, such as those used to make car tires, garden hoses, and conveyor belts.

      The lobster’s tough yet stretchy membrane could inspire more flexible body armor, particularly for areas such as elbows and knees. Materials designed to mimic lobster membranes could also be useful in soft robotics and tissue engineering. And the results shed new light on the survival of one of nature's most resilient creatures….

Bacteria Help Lung Tumors Grow

[These excerpts are from an article by Anne Trafton is in the May/June 2019 issue of MIT News.]

      MIT biologists have discovered a new mechanism that lung tumors exploit to promote their own survival: they alter the lung’s bacterial populations, provoking the immune system to create an inflammatory environment that helps tumor cells thrive.

      In mice genetically programmed to develop lung cancer, those raised in a bacteria-free environment developed much smaller tumors than mice raised under normal conditions. And treating the latter mice with antibiotics resulted in tumors that were about 50% smaller. Giving them drugs that blocked the immune response also significantly inhibited tumor development.

      “This research directly links bacterial burden in the lung to lung cancer development and opens up multiple potential ave-nues toward lung cancer interception and treatment….”

      Lung cancer, the leading cause of cancer-related deaths, kills more than 1 million people worldwide per year. Up to 70% of patients also suffer complications from bacterial infections of the lung.

      Mice (and humans) typically have many harmless bacteria in their lungs. The mice engineered to develop lung tumors harbored fewer bacterial species, but their lungs’ overall bacterial population grew significantly. That caused immune cells called gamma delta T cells to proliferate and begin secreting cytoldnes, inflammatory molecules that promote tumor growth.

      The researchers’ analysis of human lung tumors revealed unusually high numbers of gamma delta T cells and altered bacterial signals similar to those seen in the mice, so they believe drug treatments lie those that inhibited mouse tumor development are worth testing in humans.

Scientists Track Florida’s Vanishing Barrier Reef

[These excerpts are from an article by Paul Voosen in the 26 April 2019 issue of Science.]

      …Around the world, warming oceans are killing coral. In Florida…heat-induced bleaching is just the latest in a millennia-long series of insults, which have brought the reef’s growth to a standstill and left it vulnerable to erosion and rising seas. As a result, the barrier reef—the third longest in the world—is not simply dying. It appears to be vanishing.

      At stake is a 320-kilometer-long bulwark that protects the Keys from waves while providing habitat for fish and a lure for tourists. Recent measurements…have confirmed that the coral is eroding, in some places by several millimeters per year….

      The recent toll of warming, disease, and pollution on Florida’s reef has been even heavier than on some other iconic reefs, such as Australia’s Great Barrier Reef….Some species, such as the fast-growing elkhorn coral with its distinctive wide branches, have nearly vanished. A host of others have died as a disease called stony coral tissue loss has marched down the Keys….

      …Florida’s corals haven’t been healthy for millennia. Core samples from the reef record that it stopped growing 3000 years ago. Florida’s reef lies near the northern temperature limit for corals, and…a cooling trend around that time likely made the waters more prone to cold snaps that would periodically kill off corals, leaving the reefs at a delicate tipping point.

      Now although cold snaps still occur, global warming is bringing hotter summers, causing bleaching and mass die-offs. It is also raising sea level. Healthy corals readily cope with sea level rise, growing with the rising ocean. But Florida’s ailing reefs probably can’t keep pace. Anecdotes abound of patches of reef eroded flat to sand…

      A patchwork of restoration efforts, largely from nonprofit groups, continues on the reef, often aiming to replace dead coral with heat-resistant transplants. Backers should temper their expectations….

      …biologists need to introduce not just corals that can resist heat or disease, but also species that can build structure, like staghorn or elkhorn. It’s also time…to think about saving the reef structure and the services it provides, even if its coral dies….

Health for All

[This excerpt is from an editorial by Seth Berkley and Henrietta Fore in the 26 April 2019 issue of Science.]

      Imagine a world where affordable, quality health care is available to every person, and where infectious disease and infant and maternal mortality are as rare in the poorest parts as they are in wealthier countries. The world has already come a long way toward meeting this goal. But to finish the job, we need to change our thinking.

      To be sure, the incidence of child mortality and cases of deadly infectious diseases have dropped dramatically around the world. For example, polio, which once paralyzed a thousand children every day, has been eliminated from all but three countries, with just 33 cases last year. Measles cases, despite a recent, alarming global surge, are now a fraction of what they were four decades ago. All this was made possible because global health organizations and the governments of lower-income countries have worked together to provide the most vulnerable communities access to essential health care interventions, such as clean water, sanitation, and vaccinations.

      And yet, 1 in 10 children are still missing out. Most are the hardest to reach, whether they live in remote rural villages, conflict zones, among the swelling numbers of displaced people, or in rapidly growing urban slums where they might be undetected by formal health systems. Meeting their needs will require focusing more on health interventions that have both the greatest reach and are conduits to other health services for vulnerable communities. Childhood vaccination does precisely this. Vaccination reaches more children—more than 85%, who are inoculated against a range of infectious diseases—than any other health intervention globally.

      When a child gets access to vaccines, it benefits that child’s community. With vaccines come supply chains, logistics, cold storage, trained health care staff, data monitoring, disease surveillance, and health care records. Parents and siblings often come along with the child who is being vaccinated, giving them potential access to a host of other health interventions—from neonatal and maternal health care to malaria prevention measures, and sexual and reproductive health and education….

Lessons from Benjamin Franklin

[These excerpts are from an article by Maria Ferguson in the April 2019 issue of Phi Delta Kappan.]

      …Franklin’s many successes were the direct result of a childhood that included three key factors: 1) an ambitious and loving family, 2) access to educational opportunities, and 3) free time spent building his own curiosity, resilience, and independence. In policy terms, Franklin's childhood centered around three familiar issues: early childhood education, access to higher education, and social and emotional learning, three of the hottest topics in education today. It fascinated me to think that even in colonial America, these modern ideas were completely relevant. And now, 250 years later, those same factors can still make or break a childhood.

      Policy makers and education leaders know well that providing all children with the kinds of opportunities and support Franklin had is a lofty, if not unreachable, goal. But federal, state, and local leaders can still make wise investments in the areas that affect children most….

      …Families are the first, and in many ways the most consequential, influencers on a child's learning and development.

      …Despite the other dramas happening in Congress, there is some common ground between Republicans and Democrats on higher education — so the current mood is best described as “cautiously optimistic.” Never mind that the Trump administration has its own ideas about how to manage the federal role in higher education (a role they tend to define as quite limited). It is fair to say that Secretary Betsy DeVos’ actions regarding student debt forgiveness and protections for predatory providers would not pass the Ben Franklin smell test. Same for her relentless push for school choice at any cost.

      …Although keeping students physically safe is far and away the top priority for school leaders, there is also a growing consensus that schools need to consider the social and emotional needs of students as well. The last two decades saw an intense and single-minded obsession with academics and test scores that would have no doubt have alienated a student as creative and independent as young Ben Franklin. Today, education and child development experts are focused on a broader set of outcomes for children….

      It is amazing that it takes an expert-packed commission two years to tell us what we should all know already (and what Ben Franklin clearly knew): A child's education depends on many factors. In addition to high-quality learning opportunities, children also need time, love, support, and some semblance of personal freedom if they are to grow and develop into capable, productive citizens. The idea that rigorous academics alone can somehow compensate for the many things a child needs to develop has never made sense to me. That argument was at the heart of the effort to evaluate teacher performance using only test scores (a policy that has now been rejected by most state and local leaders). How can we possibly hold one person accountable for the myriad influences and circumstances in a child’s universe?...

To Improve the Curriculum, Engage the Whole System

[These excerpts are from an article by Phyllis L. Fagell in the April 2019 issue of Phi Delta Kappan.]

      …The policy obsessions of the last two decades haven’t had the desired effect. Perhaps that’s because they haven't accounted for the everyday life of teaching and learning.

      Lo and behold, maybe those of us who were so critical of No Child Left Behind and Race to the Top were right all along! If you want to improve K-12 education, you have to think about the topics kids study, the books they read, the discussions they have, the projects they complete, the experiments they conduct ... you know, the stuff that actually goes on in the class-room. If the policy wonks have finally realized that curriculum matters, then that’s a good thing. It took them long enough, but at least they’re beginning to think about the instructional core.

      Unfortunately, though, many of the people now turning their attention to the curriculum are the very same people who championed Adequate Yearly Progress, value-added teacher ratings, and other misguided accountability schemes, and it’s not clear that they’ve learned the most important lesson of the last 20 years: People who don’t understand the complexities of life in schools have no business trying to impose simplistic, one-dimensional reforms on school practitioners.

      Look, folks, a curriculum isn’t something you can just drop into a school from above, like adding fluoride to the water supply. It’s an integral part of the system, bound up with everything from teacher recruitment, hiring, and mentoring to governance, budgeting, and parent engagement. Ideally, designing and implementing a new curriculum is an opportunity to foster cohesion, trust, and professional learning, as well as to assess and respond to local interests and needs. So when I hear people argue that a simple way to improve our schools is for administrators to purchase high-quality textbooks or an “evidence-based” off-the-shelf curriculum, I’m tempted to go full-on Charlton Heston from Planet of the Apes, shouting “Keep your filthy paws off our classroom materials!”

      …Simply put, it’s always helpful to begin with an assessment of the curriculum you have, before deciding what kind of curriculum you need….

      Over several decades, our public schools were designed, explicitly, to rank and sort students into differing curricular tracks. Most schools continue to do so in one form or another, whether by placing kids into regular and honors classes, limiting enrollments in Advanced Placement courses, counseling students into (or out of) career and technical education programs, and so on, often under the guise of meeting kids’ needs for acceleration or academic support. Any effort to redesign the curriculum will have to wrestle with these long-standing practices, particularly the tracking of students of color and less affluent students into low-tier courses of study. And any changes will likely set off those parents whose kids have benefited from tracking until now….

      Most parents don’t think much about the curriculum, but they do tend to see their child's homework and grades. If the homework looks different from what they remember from their own school days, or if their kids’ grades seem to be based on new criteria, they may be tempted to complain about the school’s performance, vent their frustrations at public hearings, and lobby their board members to make the schools go back to the way things were. In short, when redesigning the curriculum, system leaders cannot afford to leave parents and other Lcommunity members out of the loop….

      Given that they will be responsible for putting any new curriculum into practice, teachers must have clarity about how they will be involved in shaping that curriculum and how their professional roles and responsibilities are going to change. Teacher leadership is critical throughout the process of curriculum planning, but even if district leaders choose to reserve key decisions for themselves, they should not try to impose a new curriculum on teachers without seeking their input. Ultimately, teachers are the ones who will have to design lesson plans, select materials, deliver the curriculum, assess student progress, and so on — and so they need to be engaged in the planning, they need to trust the process, and they need to be personally invested in the new approach….

      The last 20 years of school reform have given us good reason to be suspicious of policies and initiatives being pushed on practitioners by those who have little to no experience in schools. Yet, it’s hard to disagree with the idea that curriculum reform is sorely needed in every part of K- I2 education. Here’s hoping that it is shaped and led by people who actually know how school systems work….

How Childhood Has Changed for Tweens

[These excerpts are from an article by Phyllis L. Fagell in the April 2019 issue of Phi Delta Kappan.]

      …Every student I counsel or teach today was born after 9/11, and they’ve grown up amidst school shootings, the 24-7 news cycle, and rapid improvements in technology. Code red drills are both their normal and a source of stress. Their parents are more anxious, too, which may be contributing to a more protective parenting style. And as kids pick up on their parents’ unease, there's an added element of emotional contagion….

      And yet, whatever the changes happening around them, there are important ways in which tweens haven’t changed at all. The developmental phase is much the same for 21st-century middle schoolers as it was for those of us growing up in the 20th century. Just as I had to do in the 1980s, today’s young adolescents must figure out their identity and place in the world. As their prefrontal cortex develops, they’re malleable, impulsive, and impressionable. They’re capable of reasoning intellectually, interpreting emotions, and taking a moral stand, but they lack perspective or life experience. Sorting out social drama can consume large chunks of their time, and they tend to experience emotions in polarities. Any mishap can register as a catastrophe, and they have little understanding that negative feelings are temporary. They’re trying to figure out what coping skills work for them and where their strengths and interests align. They’re hyperaware of an invisible audience judging their every move and picking up on their shortcomings and limits. They can organize a rally for an important cause but forget to take a two-week-old banana out of their backpack. The same child who will jump from a cliff into a lake might be too self-conscious to raise his hand in class. It's a time of insecurity, hormonal changes, and contradictions. The only other time a child experiences so much development is between birth and age two.

      So how do these young people handle such transitions in a world that is changing at a similarly dizzying pace? We can’t predict the future for today’s tweens, but we do know the unique characteristics of their present-day life….

      …According to the Pew Research Center report…, 45% of teens say they’re online “almost constantly.” That’s double the number in the previous Pew report.

      On the social side, kids who are developmentally wired for adventure somehow have to preserve their reputation, stay safe, be kind, and make solid judgment calls online without the benefit of face-to-face social cues. Plus, there's the potential for permanence in everything they do. When a few boys in my 7th-grade class smeared pats of butter on all the cars in the school parking lot in 1986, no one beamed it out to the world. We were just as prone to mischief and mistakes a generation ago, but our transgressions could fade into the ether.

      The butter-smearing incident seems rather quaint today. Now, principals have to call police if a 12-year-old forwards a classmate’s nude snapshot across state lines and unknowingly violates child pornography laws. Technology has brought new avenues for harassment, too. One study found that more than 25% of middle schoolers reported being a victim of electronic dating aggression, and more than 10% said they were a perpetrator….Kids must consider the long-term impact of more mundane behaviors, too….

      …Researchers at the University of Kentucky recently found that middle school girls and boys not only tend to feel dissatisfied with their bodies, but their negative feelings increase as they spend more time on social media….

      …Simply having a phone on hand in class can affect students’ grades. A study in Educational Psychology found a causal link between students’ use of cell phones in class and lower exam scores….Kids are losing sleep because of technology, too. For some, it feels rude to drop out of a group chat, even if it’s 1 a.m. and they’re exhausted. Others have difficulty disengaging from gaming or other online interests.

      Technology is even changing the age-old phenomenon of cheating. A 2009 Common Sense Media survey found that 35% of teens with cell phones admitted to cheating with them at least once. Half of those polled admitted to cheating using the internet, while 38% had plagiarized work from websites. And according to a survey by McAfee, a computer security firm, 29% of students admit to using tech devices to cheat in school….

      The internet also is exposing kids to darker and more mature information earlier, whether it’s pornography or graphic images of a school shooting. According to Break the Cycle, the average age of first exposure to pornography is now around age 11….

      On the plus side, there’s less incentive to memorize facts when most information can be Googled, which means kids are more likely to focus on making connections across ideas and thinking outside the box. With half of all U.S. jobs at risk of being automated in the coming years, kids will need to be able to think critically, innovate, and solve problems to perform the new jobs that emerge….

      The good news is that parents have become more forth-coming about their children’s mental health struggles, whether they’re disclosing a diagnosis or a therapist’s treatment plan. They’re also more honest about struggles at home, such as a divorce or job loss. At the same time, however, kids have become less resilient and feel less in control of their fate, at least in part because parents tend to afford them less freedom and autonomy than in the past.

      …growing numbers of educators are coming to understand that when we deprive kids of play, we put them at risk for depression and anxiety.

      Overall, I’ve observed more parents and schools expressing interest in building kids’ character, prioritizing authentic inclusion, and encouraging moral action. In the age of the selfie, more adults are recognizing that we need to de-emphasize “likes” on social media and spend more time underscoring the importance of empathy. Middle schoolers have always been tuned into justice and fairness, but today’s tweens are perhaps even more likely to take on an activist role, whether they lobby for gun control, the environment, or immigration rights….

      In some ways, kids are growing up faster today. Parents can no longer shield their children from bad news, particularly if they’re carrying a computer in their pocket. In other ways, they’re growing up slower. As they spend more time communicating online, they’re spending less time together experimenting, taking risks, and dating. That said, some aspects of being this age haven’t changed at all. A principal once told me that he loves this age group because the same child can present as 13 going on three, or 13 going on 30. No matter how much their landscape changes, that’s as true today as it was a generation ago.

Childhood, Then and Now

[These excerpts are from an editrial by Rafael Heller in the April 2019 issue of Phi Delta Kappan.]

      April 1919 — exactly a century ago, on the nose — marked the end of President Woodrow Wilson’s “Children’s Year,” a national campaign to improve infant and maternal health, provide more social services to needy families, increase school enrollments, and further reduce Americans’ reliance on child labor (which had been declining steadily for two decades).

      At the time, the typical American childhood included a lot more sickness (and 1 in 10 babies died in childbirth), a lot less schooling, and a lot more manual labor than it does today. In 1919, roughly a million 10- to 15-year-olds, or roughly 8% of the age group, spent their days working on farms, in factories, or on the street. Close to 80% of children ages 5 to 17 were enrolled in school, but their numbers dwindled in the later grades — only about a quarter of 14- to 17-year-olds attended high school, and only about 1 in 10 graduated….

      As federal initiatives go, the Children’s Year looks to have been fairly productive. A national commission met in Washington, D.C., followed by a series of regional meetings meant to rally public and political support for efforts to help the most vulnerable children. In turn, most states proceeded to create child welfare agencies, while, across the country, millions of women mobilized to collect data on children's health and advocate for better education and recreational activities for kids.

      No doubt, the lives of American children have changed dramatically since then. However, it’s tricky to compare the experience of childhood today with that of previous generations. For example, historians argue that it wasn’t until the early 20th century, as a large middle class began to coalesce, that Americans began to conceive of childhood as the sort of special, happy stage of life that we now take to be the norm. Nor did Americans think of the teen years as a distinct phase of childhood at all until high school enrollments took off in the 1920s and ‘30s….

      But whatever our point of comparison, one thing is certain about childhood today: American children of all backgrounds now spend much more time in school than at any time in the past — not just dramatically more time than in 1919 but also, given rising trends in high school attendance and graduation, significantly more time than just a few years ago. As the sociologist Annette Lareau points out in this issue, educators have always played an exceptionally important role in children’s lives. Today more than ever.

New Climate Models Forecast a Warming Surge

[These excerpts are from an article by Paul Voosen in the 19 April 2019 issue of Science.]

      For nearly 40 years, the massive computer models used to simulate global climate have delivered a fairly consistent picture of how fast human carbon emissions might warm the world. But a host of global climate models developed for the United Nations’s next major assessment of global warming, due in 2021, are now showing a puzzling but undeniable trend. They are running hotter than they have in the past. Soon the world could be, too.

      In earlier models, doubling atmospheric carbon dioxide (CO2) over preindustrial levels led models to predict somewhere between 2°C and 4.5°C of warming once the planet came into balance. But in at least eight of the next-generation models, produced by leading centers in the United States, the United Kingdom, Canada, and France, that “equilibrium climate sensitivity” has come in at 5°C or warmer. Modelers are struggling to identify which of their refinements explain this heightened sensitivity before the next assessment from the United Nations’s Intergovernmental Panel on Climate Change (IPCC). But the trend “is definitely real. There’s no question,” says Reto Knutti, a climate scientist at ETH Zurich in Switzerland. “Is that realistic or not? At this point, we don’t know.”

      That’s an urgent question: If the results are to be believed, the world has even less time than was thought to limit warming to 1.5°C or 2°C above preindustrial levels—a threshold many see as too dangerous to cross. With atmospheric CO2 already at 408 parts per million (ppm) and rising, up from pre-industrial levels of 280 ppm, even previous scenarios suggested the world could warm 2°C within the next few decades. The new simulations are only now being discussed at meetings, and not all the numbers are in….

      Many scientists are skeptical, pointing out that past climate changes recorded in ice cores and elsewhere don’t support the high climate sensitivity—nor does the pace of modern warming….

Cold Comfort

[This excerpt is from an article by Steve Minsky in the April 2019 issue of Scientific American.]

      …When the forecast warned us a couple of days earlier that Arctic air was looming, the president issued a sincere and helpful tweet, which ended with: “What the hell is going on with Global Warning [sic]? Please come back fast, we need you!” And being the most powerful man on Earth, he was successful in his polite imploration. On February 4 the Chicago temperature reached 51 degrees. And the next day the Big Apple basked in a sunny 65.

      The Arctic is warming at twice the rate as the global average. This heat can help disrupt the polar vortex, a steady wind pattern that usually stays focused on circling the North Pole. A wobbly jet stream then runs into a brick wall of that Arctic air, which is still pretty frosty by human standards, and both wind up hundreds of miles farther south than they usually belong. And for a few days we in the Deep South—by which I mean Chicago or New York compared with the Arctic—freeze our butts off. But less than a week after this most recent vortex disruption, thanks to some warm air coming up from the real South, I was walking outside without a coat. On a date when the average high temperature is about 40.

      Like so much else we are currently living through, this kind of thermometer ride is not normal. Or it didn’t used to be, anyway.

      Of course, scientists have been waming—sorry, warning—that warming can have these very effects. Climate change deniers may sneer, “So when it’s warmer than usual, that’s because of global warming. And when it’s colder, that's also because of global warming?” Well, yes. And anybody who just can’t accept these kinds of seemingly paradoxical situations needs to reflect on the expression “freezer burn.”…

Failing Successfully

[These excerpts are from an article by Rachel Nuwer in the April 2019 issue of Scientific American.]

      People often say that “failure is the mother of success.” This cliche might have some truth to it, but it does not tell us how to actually turn a loss into a win….”we know we shouldn’t give up when we fail—but in reality, we do.”

      …One study reported, for example, that the sooner and more often students fail at a task, such as building a robot, the sooner they can move forward and improve. Another confirmed that feedback on failures is most constructive when the giver comes across as caring, and the receiver is prepared to weather negative emotions.

      …study focused on overcoming one fundamental, everyday form of failure: not completing a task. They asked 131 undergraduates to write an essay about their school experiences. Half of the students received instructions for structuring their writing, and half were left to their own devices; all, however, were stopped prior to finishing. Afterward the researchers found that those in the structured group were more motivated to complete their essays, compared with those who lacked guidance—even if the latter were closer to being done. Knowing how to finish, in other words, was more important than being close to finishing.

      The researchers dubbed this finding “the Hemingway effect,” for the author’s self-reported tendency to stop writing only when he knew what would happen next in the story—so as to avoid writer’s block when he returned to the page….learning how to fail temporarily can help people avoid becoming permanent failures at many tasks, such as completing a dissertation, learning a language or inventing a new technology.

      Demystifying failure and teaching students not to fear it make goals more attainable, says Stephanie Couch, executive director of the Lemelson-MIT Program….

Low-Tech Climate Fix

[These excerpts are from an editorial by Hans de Groot in the April 2019 issue of Scientific American.]

      Climate change disproportionately affects the world’s most vulnerable people, particularly poor rural communities that depend on the land for their livelihoods and coastal populations throughout the tropics. We have already seen the stark asymmetry of suffering that results from extreme weather events, such as hurricanes, floods, droughts, wildfires, and more.

      For remedies, advocates and politicians have tended to look to-ward cuts in fossil-fuel use or technologies to capture carbon before it enters the atmosphere—both of which are crucial. But this focus has overshadowed the most powerful and cost-efficient carbon capture technology in the world. Recent research confirms that forests are absolutely essential in mitigating climate change, tha.nks to their ability to absorb and sequester carbon. In fact, natural climate solutions such as conservation and restoration of forests, along with improvements in land management, can help us achieve 37 percent of our climate target of limiting warming to a maximum of two degrees Celsius above preindustrial levels, even though they currently receive only 2.5 percent of public climate financing.

      Forests’ power to store carbon dioxide is staggering: one tree can store an average of about 48 pounds in one year. Intact forests could take in the CO2 emissions of some entire countries.

      For this reason, policy makers and business leaders must create and enforce policies to prevent deforestation; foster reforestation of degraded land; and promote the sustainable management of standing forests in the fight against climate change. Protecting the world’s forests ensures they can keep performing essential functions such as producing oxygen, filtering water and supporting biodiversity. Not only does all the world's population depend on forests to provide clean air, clean water, oxygen and medicines, but 1.6 billion people rely on them directly for their livelihoods.

      Unfortunately, a huge amount of forest continues to be converted into agricultural lands to produce a handful of resource-intensive commodities—despite zero-deforestation commitments from companies and governments. So now is the time to increase forest protection and restoration. This action will also address a number of other pressing global issues. For example, increasing tree cover can help tackle the problem of food security in many areas: trees can enhance farm productivity and give farmers another source of revenue through the sale of fruits, nuts or timber—all the while storing carbon dioxide—in a practice known as agro-forestry. It is estimated that increased investment in this area could help sequester up to 9.28 gigatons of carbon dioxide while saving a net $709.8 billion by 2050. In productive landscapes where it would be difficult to increase tree cover dramatically, agroforestry serves as an attractive compromise….

      Landscape restoration promises an unparalleled return on investment, in terms of ecosystem services and carbon sequestered and stored. It could potentially sequester up to 1.7 gigatons of carbon dioxide every year….

The WHO Takes a Reckless Step

[This excerpt is from an editorial by the editors in the April 2019 Scientific American.]

      …To include TCM in the ICD is an egregious lapse in evidence-based thinking and practice. Data supporting the effectiveness of most traditional remedies are scant, at best. An extensive assessment was done in 2009 by researchers at the University of Maryland: they looked at 70 review papers evaluating TOM, including acupuncture. None of the studies proved conclusive because the data were either too paltry or did not meet testing standards.

      To be sure, many widely used and experimentally validated pharmaceuticals, including aspirin, decongestants and some anti-cancer chemotherapies, were originally derived from plants or other natural sources. Those drugs have all gone through extensive clinical testing of safety and efficacy, however. Giving credence to treatments that have not met those standards will advance their use but will also diminish the WHO’s credibility.

      China has been pushing for wider global acceptance of traditional medicines, which brings in some $50 billion in annual revenue for the nation’s economy. And in 2016 Margaret Chan, then the WHO director, praised China’s plans to do so. But while it’s a good idea to catalogue TCM and make health workers aware of treatments used by millions, their inclusion in the ICD recklessly equates them with medicines that have undergone clinical trials.

      In China, traditional medicines are unregulated, and they frequently make people sick rather than curing them. One particularly troublesome ingredient, aristolochic acid, is commonly used in traditional remedies and has been linked to fatal kidney damage and cancers of the urinary tract.

      A 2018 study in the British Journal of Clinical Pharmacology tested 487 Chinese products taken by sick patients and discovered 1,234 hidden ingredients, including approved and banned Western drugs, drug analogues and animal thyroid tissue. And in 2012 a team led by Megan Coghlan, then at Murdoch University of Australia, identified the DNA sequences in 15 samples of traditional medicines in the form of powders, tablets, capsules, bile flakes and herbal -teas. The samples also contained plants that produce toxic chemicals and animal DNA from vulnerable or endangered species (the Asiatic black bear and saiga antelope, for example) and other creatures protected by international laws.

      Thus, the proliferation of traditional medicines would have significant environmental impacts on top of the negative health effects. It would contribute to the destruction of ecosystems and increase the illegal trade of wildlife. China announced last October that it was legalizing the controlled trade of rhinoceros horn and tiger bone. (The move was postponed in November, following a global outcry.) Both are believed by practitioners to have the power to cure a range of ailments, from fever to impotence—although no study has found any beneficial outcome of ingesting either. Allowing even the controlled harvest of otherwise endangered creatures will boost illegal poaching, critics say.

      Until they undergo rigorous testing for purity, efficacy, dosage and safety, the WHO should remove traditional medicines from its list. These remedies should be given the same scrutiny as other treatments before being included in standard care practices.

Beliefs in Aliens, Atlanis Are on the Rise

[These excerpts are from an article by Lizzie Wade in the 12 April issue of Science.]

      …Common beliefs include that aliens helped build the Egyptian and Mayan pyramids, that refugees escaping Atlantis brought technology to cultures around the world, and that European immigrants were the original inhabitants of North America.

      …41% of Americans believed that aliens visited Earth in the ancient past, and 57% believed that Atlantis or other advanced ancient civilizations existed. Those numbers are up from 2016, when the survey found that 27% of Americans believed in ancient aliens and 40% believed in Atlantis.

      ….He can’t say exactly what is driving the rise in such ideas, but cable TV shows like Ancient Aliens (which has run for 13 seasons) propagate them, as does the internet.

      …Almost all such claims assume that ancient non-European societies weren’t capable of inventing sophisticated architecture, calendars, math, and sciences like astronomy on their own. “It’s racist at its core,” says Kenneth Feder, an archaeologist at Central Connecticut State University in New Britain….

New Species of Ancient Human Unearthed

[These excerpts are from an article by Lizzie Wade in the 12 April 2019 issue of Science.]

      A strange new species may have joined the human family. Human fossils found in a cave on Luzon, the largest island in the Philippines, include tiny molars suggesting their owners were small; curved finger and toe bones hint that they climbed trees. Homo luzonensis, as the species has been christened, lived some 50,000 to 80,000 years ago, when the world hosted multiple archaic humans, including Neanderthals and Denisovans, and when H. sapiens may have been making its first forays into Southeast Asia….

      The discovery echoes that of another unusual ancient hominin—the diminutive H. floresiensis, or “hobbit,” found on the island of Flores in Indonesia. “One is interesting. Two is a pattern,” says Jeremy DeSilva, an expert on Homo foot bones at Dartmouth College. He and others suspect the islands of Southeast Asia may have been a cradle of diversity for ancient humans, and that H. luzonensis, like H. floresiensis, may have evolved small body size in isolation on an island….

      The teeth show a unique mosaic of traits found separately in other Homo species. The premolars are about the size of ours, but instead of a single root they have two or three—a primitive feature. The molars are much more modern, with single roots, but “incredibly small” at only 10 millimeters across and 8 millimeters long, says Florent Detroit, a paleoanthropologist at the Museum of Man in Paris who worked with Mijares. That’s even smaller than those of H. floresiensis. Tooth size tends to correlate with body size, so it’s possible that H. luzonensis itself was tiny, Detroit says. But only a complete arm or leg bone will say for sure.

      The long, curved fingers and toes resemble those of australopithecines like Lucy, an early human ancestor thought to have both walked upright and swung through the trees….

      Not everyone is ready to embrace these teeth and skeletal fragments as a separate species, rather than a locally adapted population of, say, H. erectus, an older hominin that lived in Asia for millennia….

      Regardless of whether H. luzonensis was its own species, it may have evolved in isolation for hundreds of thousands of years. Butchered rhino bones on Luzon date to 700,000 years ago, though researchers don’t yet know which human species was responsible….

Reverse Global Vaccine Dissent

[This editorial by Heidi J. Larson and William S. Schulz is in the 12 April 2019 issue of Science.]

      This year, the World Health Organization named vaccine hesitancy as one of the top 10 global health threats, alongside threats as grave as climate change, antimicrobial resistance, Ebola virus, and the next influenza pandemic. What happened? How did vaccine reluctance and refusal become such a major risk?

      The concerns driving antivaccine sentiment today are diverse. For example, from 2003 to 2004, a vaccine boycott in Nigeria's Kano State sparked the retransmission of polio across multiple countries as far as Indonesia. Rumors of vaccine contamination with antifertility agents contributed to distrust and reinforced the boycott, costing the Global Polio Eradication Initiative over U.S. $500 million to regain the progress that was lost. In Japan, vaccination against human papilloma virus plummeted to almost zero after young women complained of movement disorders and chronic pain, causing the government to suspend proactive recommendation of the vaccine nearly 6 years ago. Similar episodes occurred in Denmark, Ireland, and Colombia as YouTube videos of the girls' symptoms spread anxiety, despite evidence of the vaccine's safety.

      The global surge in measles outbreaks has been exacerbated by vaccine refusers. In 2015, the measles strain that sparked the Disneyland outbreak came from visitors from the Philippines, infecting people who had refused vaccination. And in Indonesia, Muslim leaders issued a fatwa against a measles vaccine containing “haram” porcine compounds, while naturopathic “cupping” methods were promoted on Facebook as an alternative to vaccination. In 2018, a mix of political, religious, and alternative health antivaccine messages circulated on WhatsApp and Facebook in Southern India, disrupting a local measles-rubella vaccination campaign.

      The phenomenon of vaccine dissent is not new. The pages of 18th-century London antivaccination pamphlets bristle with many of today’s memes, but these ideas now spread over unprecedented distances with remarkable speed, clustering in online neighborhoods of shared beliefs. This clustering can tear the protective fabric—the “herd (community) irnmunity”—that the majority of vaccine acceptors have woven. As the portion of the community that is vaccinated decreases, there is less protection for others who may be too young, unable, or choose not to be vaccinated. For some diseases, it only takes a small minority to disrupt the protective cover.

      It is just over 20 years since British physician Andrew Wakefield sowed seeds of doubt about the safety of the MMR (measles, mumps, rubella) vaccine, suggesting a link between the vaccine and autism. Suspicions around the vaccine traveled globally, instilling anxiety among the most and least educated alike. The discredited Wakefield alone, though, cannot be blamed for today’s waves of vaccine discontent. He seeded a message on the eve of a technological revolution that disrupted business, politics, societies, and global health. The same year that Wakefield published his research, Google opened its doors. The launches of Facebook, YouTube, Twitter, and Instagram soon followed. These social media platforms have magnified individual sentiments that might have stayed local. Emotions are particularly contagious on social media, where personal narrative, images, and videos are shared easily.

      Today’s tech companies are now being called to account for their role in spreading vaccine dissent. Last month, the American Medical Association urged the chief executives of key technology companies to “ensure that users have access to scientifically valid information on vaccinations.” But this is not merely an issue of correcting misinformation. There are social networks in which vaccine views and information are circulating in online communities, where vaccine choices become part of one’s overall identity.

      To mitigate the globalization of vaccine dissent, while respecting legitimate sharing of concerns and genuine questions, a mix of relevant expertise is needed. Technology experts, social scientists, vaccine and public health experts, and ethicists must convene and take a hard look at the different roles each group has in addressing this challenge. It needs everyone’s attention.

Does Fossil Site Record Dino-killing Impact?

[These excerpts are from an article by Colin Barras in the 5 April 2019 issue of Science.]

      A fossil site in North Dakota records a stunningly detailed picture of the devastation minutes after an asteroid slammed into Earth about 66 million years ago, a group of researchers argues in a paper published online this week. Geologists have theorized that the impact, near what is now the town of Chicxulub on Mexico’s Yucatan Peninsula, played a role in the mass extinction at the end of the Cretaceous period, when all the dinosaurs (except birds) and much other life on Earth vanished.

      The team, led by Robert DePalma…, says it has uncovered a record of apocalyptic destruction 3000 kilometers from Chicxulub. At the site, called Tanis, the researchers say they have discovered the chaotic debris left when tsunamilike waves surged up a river valley. Trapped in the debris is a jumbled mess of fossils, including freshwater sturgeon that apparently choked to death on glassy particles raining down from the fireball lofted by the impact.

      …The deposit may also provide some of the strongest evidence yet that nonbird dinosaurs were still thriving on impact day….

      But not everyone has fully embraced the find, perhaps in part because it was first announced to the world last week in an article in The New Yorker. The paper, published in the Proceedings of the National Academy of Sciences (PNAS), does not include all the scientific claims mentioned in The New Yorker, including that numerous dinosaurs as well as fish were buried at the site….

      In the early 1980s, the discovery of a clay layer rich in iridium, an element found in meteorites, at the very end of the rock record of the Cretaceous at sites around the world led researchers to link an asteroid to the End Cretaceous mass extinction. A wealth of other evidence has persuaded most researchers that the impact played some role in the extinctions. But no one has found direct evidence of its lethal effects.

      DePalma and his colleagues say the killing is captured in forensic detail in the 1.3-meter-thick Tanis deposit, which they say formed in just a few hours, beginning perhaps 13 minutes after impact. Although fish fossils are normally deposited horizontally, at 'Tanis, fish carcasses and tree trunks are preserved haphazardly, some in near vertical orientations, suggesting they were caught up in a large volume of mud and sand that was dumped nearly instantaneously. The mud and sand are dotted with glassy spherules—many caught in the gills of the fish—isotopically dated to 65.8 million years ago. They presumably formed from droplets of molten rock launched into the atmosphere at the impact site, which cooled and solidified as they plummeted back to Earth. A 2-centimeter-thick layer rich in telltale iridium caps the deposit.

      Tanis at the time was located on a river that may have drained into the shallow sea covering much of what is now the eastern and southern United States. DePalma’s team argues that as seismic waves from the distant impact reached Tanis minutes later, the shaking generated 10-meter waves that surged from the sea up the river valley, dumping sediment and both marine and freshwater organisms there. Such waves are called seiches: The 2011 Tohoku earthquake near Japan triggered 1.5-meter-tall seiches in Norwegian fjords 8000 kilometers away….

      Until a few years ago, some researchers had suspected the last dinosaurs vanished thousands of years before the catastrophe. If Tanis is all it is claimed to be, that debate—and many others about this momentous day in Earth’s history—may be over.

A Recharge Revolution

[These excerpts are from an article by Jennifer Marcus in the Spring 2019 issue of the USC Trojan Family Magazine.]

      …One hour of sunlight provides more than all of the energy consumed on the planet in a year. Solar panels are one way for us to tap into some of this universal, free power source—but what happens on a rainy day?

      Solar panels can only generate power when the sun shines on them, and wind turbines can only generate power when the wind blows. The ups and downs in supply from these renewable sources make it difficult for power companies to rely on them to meet customer demand in real time….

      If batteries could store surplus energy to keep a consistent supply on hand, that sporadic unreliability could cease to be a problem. That’s why Prakash and Narayan have developed a water-based organic battery that is long-lasting and built from inexpensive, eco-friendly components. This new design uses no metals or toxic materials and is intended for use in solar and wind power plants, where its large-scale storage capacity could make the energy grid more resilient and efficient.

      Their design differs from the conventional batteries familiar to consumers. It’s called a redox flow battery and consists of two tanks of fluid, which store the energy. The fluids are pumped through electrodes that are separated by a membrane. The fluid contains electrolytes, and ions and electrons flow from one fluid into the other through the membrane and then the electrode, creating an electric current….

      Resembling a small building, the redox flow battery Prakash envisions would act as a battery farm of sorts, storing surplus energy generated from nearby solar panels or wind turbines….

      The new water-based organic flow batteries last for about 5,000 recharge cycles—five times longer than traditional lithium-ion batteries—giving them about a 15-year life span. At wok one-tenth the cost of lithium-ion batteries, they’re also much cheaper to manufacture thanks to their use of abundant, sustainable materials.

      Narayan and Prakash have tested a 1-kilowatt flow battery capable of powering the basic electricity needs of a small house….

      With annual global energy consumption projected to continue increasing by about 50 percent in the next 30 years, relying on renewable resources is one of the most important motivators driving sustainable technology research forward. The world can’t continue to rely on fossil fuels to meet energy demands without devastating environmental consequences….

      Marinescu focuses on gathering energy harvested from sunlight and storing it as chemical energy—much like plants do through photosynthesis. She and her team are working on a way to convert that stored energy into electricity by using what are called metal-organic frameworks. These flexible, ultra-thin and highly porous crystalline structures have unique properties that have been used by scientists primarily to absorb and separate different types of gas. Their use for energy applications seemed like a lost cause because researchers believed they couldn't conduct electricity. But Marinescu’s work has changed that.

      In the lab, her team experimented with the materials. Typically, electrons were localized in bonds (which prevents them from conducting any electricity). But the team created new materials with the electrons spread over multiple bonds, developing solids that could now carry electric current the same way that metals do….The frameworks developed by her research group contain inexpensive elements and can transform acidic water into hydrogen. This represents a huge advance, as these materials could one day be used in technologies like those for hydrogen-powered vehicles. They can also be spread thin across a huge area: It only takes 10 grams of the material to coat a surface the size of a football field.

      The technology opens the door for storing renewable energy at a huge, almost unthinkable scale….

Science during Crisis

[These excerpts are from an editorial by Rita R. Colwell and Gary E. Machlis in the 5 April 2019 issue of Science.]

      In April 1902, on the Caribbean island of Martinique, La Commission sur le Vulcan convened to make a fateful decision. Mt. Pelee was sending smoke aloft and spreading ash across the capital city of Saint-Pierre. Comprising physicians, pharmacists, and science teachers, the commission debated the danger of an eruption and the burden of evacuation, and judged the safety of the city’s population to be “absolutely assured.” Weeks later, Mt. Pelee erupted and approximately 30,000 residents died within minutes, leaving only two survivors. Environmental crises require pivotal decisions, and such decisions need timely, credible scientific information and science-based advice. This requirement is the focus of a report released last month by the American Academy of Arts and Sciences, calling attention to improvements in the operation and delivery of science during crises.

      Science has provided essential data and insight during disaster responses in the United States, including the World Trade Center attack (2001), Deepwater Horizon oil spill (2010), Hurricane Sandy (2012), and the Zika virus epidemic (2016). The context of scientific work done during such major disasters differs from that of routine science in several ways. Conditions change rapidly—wildfires spread swiftly, hurricanes intensify within hours, and aftershocks render buildings unsafe. In such scenarios, scientists must respond within tightly constrained time frames to collect data, do analyses, and provide findings that normally would involve months or years of work. Decision-makers need actionable information (such as risk assessments or mitigation techniques), yet scientific information is only one of many inputs to disaster response. Because communication networks may be severely disrupted, as occurred in Puerto Rico during Hurricane Maria (2017), delivery of science becomes even more difficult.

      Thus, science during crisis involves specialized actions such as heightened attention to coupled human-natural systems and cascading consequences. Important responses include rapid establishment of interdisciplinary scientific teams, local knowledge quickly integrated into scientific work, clear and compelling visualization of results, and concise communication to decision-makers, disaster-response specialists, and the public….

      In 2018, the United States experienced 14 weather and climate disasters with losses exceeding $1 billion each and a total of 247 lives lost. The summer wildfire season in the American West will soon again begin, followed by the start of the 2019 hurricane season in the Atlantic Ocean. There will be new disasters and science will play a critical role, informing and guiding decisions governing disaster response and recovery. Science during a crisis must be as effective as possible….

A Deadly Ambhibian Disease Goes Global

[These excerpts are from an article by Dan A. Greenberg and Wendy J. Palen in the 29 March 2019 issue of Science.]

      …Three decades ago, biologists began to report the decline or extinction of amphibian populations around the world. This concerted global phenomenon spawned a proliferation of hypotheses, especially to explain “enigmatic” declines in remote places, where neither habitat loss nor direct exploitation were apparent. The suspected culprit was a species new to science: Batraehochytrium dendrobatidis (Bd), a fungal pathogen found in amphibian skin that belongs to the chytrids, a group of otherwise benign soil and water fungi.

      Bd is one of two species responsible for chytridiomycosis, the disease that appeared to be causing mass die-offs of amphibians. Bd is present in much of the world, but in the past century, a group of pathogenic strains originated in and spread from Asia; this spread coincided with the expansion of the global trade in live amphibians….Scientists have only been able to guess at the scale of damage caused by Bd to amphibian populations across the world, mostly because the baseline population data needed to decipher where and when species were lost through this disease have not been available.

      Scheele et al. overcame these data limitations to reconstruct the biodiversity impact of the global spread of pathogenic Bd. They compiled a detailed dataset of chytridiomycosis-associated declines from both published records and interviews with regional experts around the world. They estimate that chytridiomycosis has contributed to the decline or extinction of at least 501 amphibian species, earning Bd the inauspicious title of the most destructive pathogen for biodiversity ever recorded. The analysis suggests that of the 501 species, 90 are presumably extinct, with another 124 suffering severe declines. Many of these species belong to a few particularly susceptible frog lineages.

      Because ecology and life history shape the susceptibility of species to Ed, the authors used their dataset to test for commonalities in species loss across six continents. The results suggest that large-bodied, range-restricted, and aquatic-associated species are most at risk of severe declines from chytridiomycosis. This information is vital for identifying regions that have the right environmental conditions for Bd and many potential hosts and where pathogen introduction could thus trigger extinctions. This information is particularly relevant given concern about the spread of pathogenic Bd strains to amphibian evolutionary hotspots where the pathogen is thought to be absent or rare, mainly oceanic islands like Papua New Guinea and Madagascar.

      The authors’ data also suggest that chytridiomycosis-associated declines peaked in the 1980s in many regions, just as scientists were beginning to note these enigmatic losses (3). They conclude that the severity of declines may be dwindling over time. It remains unclear whether this is a sign of hosts and pathogen achieving a stable coexistence or merely a lull after the first of many waves of outbreaks….

      Scientific understanding of Ed is still unfolding decades after its discovery, raising the ominous possibility that our ability to react to complex cases of biodiversity decline may always lag behind the emergence of threats. As studies such as that by Scheele et al. reconstruct what is already lost, there is a critical need to leverage these data into proactive management that considers multiple threats.

      Bd is but one more nail in the coffin for the state of amphibians globally. Habitat loss, exploitation, and climate change remain the main threats for thousands of species. These stressors often act in concert, but clear management actions exist to address at least some of them: protect habitat, limit collection of wild populations, and restrict trade. By contrast, there appear to be few viable management actions available once pathogenic Bd strains have established; if trade restrictions fail, then the only hope will be that evolutionary rescue can save at least some species. Moving forward, conservationists must carefully consider what management solutions are going to be most effective for each region, with habitat loss, climate change, and pathogen introduction all simultaneously threatening amphibian diversity….

Natural History Museums Face their Own Past

[These excerpts are from an article by Grethchen Vogel in the 29 March 2019 issue of Science.]

      Step into the main hall of the Natural History Museum here and you’ll be greeted by a towering dinosaur skeleton, the tallest ever mounted. Nearly four stories high and twice as long as a school bus, the sauropod Giraffatitan brancai was the largest dinosaur known for more than a half-century. It has been a crowd magnet since it was first displayed in 1937.

      But the tidal flats Giraffatitan bestrode 150 million years ago weren’t in Europe. It lived in eastern Africa, today’s Tanzania, much of which was a German colony when the fossil was unearthed in the early 1900s. Now some Tanzanian politicians argue the fossils should return to Africa.

      Berlin’s Natural History Museum isn’t the only one facing calls for the return of fossils, which echo repatriation demands for human remains and cultural artifacts. Many specimens were collected under conditions considered unethical today, such as brutal colonial rule that ignored the ownership rights and knowledge of indigenous people….

      Although German paleontologists have traditionally gotten credit for discovering Giraffatitan, it was in fact local residents, who knew the bones and used them in religious rites, who guided the foreigners to the find….

      The Natural History Museum in London is now facing at least three repatriation requests for prominent specimens: Gibraltar has asked for two Neanderthal skulls; Chile has requested exquisitely preserved skin, fur, and bones from a 12,000-year-old giant ground sloth (Mylodon darwinii); and Zambia has asked for the Broken Hill skull, a famous early hominin about 300,000 years old that’s usually classified as Homo heidelbergensis. < /p>

      Many of these objects were sent to Europe without much thought given to who might own them. The first Neanderthal discovered, for example, was unearthed in 1848 by a British lieutenant stationed in what was then the U.K. military base of Gibraltar. Some 70 years later, British archaeologist Dorothy Garrod found a Neanderthal child’s skull in a Gibraltar cave and also sent it to England for study….

      Chile is making a similar claim for the Mylodon remains. European explorers found them in the 1890s and shipped them home without permission from local authorities. They have ended up distributed among half a dozen museums in Europe. Chile retains a few smaller Mylodon bones and dung, but the spectacularly preserved skin specimens are a key part of its natural heritage….

      Giraffatitan, for its part, will likely stay put. Rather than press for its return, the Tanzanian government has said it would prefer support for excavating new fossils, training local paleontologists, and strengthening its museums….

Integrating Tactics on Opioids

[These excerpts are from an editorial by Alan I. Leshner in the 29 March 2019 issue of Science.]

      Many parts of the world are in the middle of an opioid addiction crisis. It is an equal opportunity destroyer, affecting rich and poor, urban and rural people alike. The current epidemic differs from the long-standing heroin addiction problem in its broader demographic and in that it has resulted from inappropriate marketing and overprescription of pain medicines and the intrusion of powerful and lethal synthetic opioids. The magnitude of the crisis is also unprecedented: In the United States alone, more than 2 million people are estimated to have “opioid use disorder,” and 47,000 people died of an opioid overdose in 2017. Traditional strategies for dealing with addiction have had limited success. They have primarily used parallel tactics of “supply control” (limiting availability) and “demand control” (trying to prevent or reduce use), which might be considered as criminal justice and public health approaches. But this side-by-side approach may be counterproductive. Last week, the U.S. National Academies of Sciences, Engineering, and Medicine CP released a report on the state of medication-based treatments for opioid addiction. What is clear is that in addition to the need for more research, the nature of the epidemic requires new approaches that integrate public health, regulatory, and criminal justice strategies.

      Although additional studies would be useful in refining strategies, there already exists a body of evidence that should be used to improve current tactics. Take the case, for example, of addicted individuals who are accused of or have committed crimes. If these individuals are not treated while they are under criminal justice control, the rates of recidivism to both crime and drug use upon release are extremely high. If, however, they are treated while incarcerated and after release, recidivism rates fall substantially, as do post-release mortality rates. In addition, only 25 to 30% of prison and jail inmates are estimated to receive any drug abuse treatment, whereas over 50% suffer from substance use disorders. Even more dramatic, only 5% of justice-referred individuals receive any of the medications approved by the U.S. Food and Drug Administration (FDA) for their addiction, despite substantial evidence of their effectiveness. The conclusion from that effectiveness research is obvious: It is foolish and borders on being unethical to withhold medical treatment from people with opioid use disorder who are under criminal justice control. There are extensive data that could provide better guidance for refining prevention, prescription, and regulatory policies as well.

      The lack of successful strategies to address opioid addiction results in part from other barriers to progress on this epidemic. These include misunderstandings about the nature of addiction and the lack of medications used to treat it, as well as the insidious ideology and stigma that have long surrounded the issue of drug use and addiction. A large body of scientific evidence has established that addiction is a chronic disease of the brain that requires medical intervention. It is not a moral weakness or a failure of will….

      To make real progress in tackling the opioid epidemic, people on all sides of the issue will have to give up many of their long-held biases and beliefs. Prog-ess will require more researchers working across fields and more informed public health, regulatory, and criminal justice officials, as well as members of the public, agreeing on the actual nature of the opioid crisis and science-based, integrated strategies to deal with it.

Big Floods Highlight Prediction Needs

[This excerpt is from a news article in the 29 March 2019 issue of Science.]

      Two major floods in March wrought destruction in the United States and Mozambique, highlighting that scientists are falling short in accurately predicting high water so communities around the world can prepare. Above-average winter rainfall helped swell the Missouri River to record levels, flooding thousands of homes and destroying stored crops. U.S. government forecasters predict more than 200 million Americans and 25 states may be affected by “unprecedented” flooding later this spring. The inundation has shocked many residents, which likely reflects shortcomings in U.S. floodplain maps that predict where large floods will strike….The maps don’t include many small streams, and many are dated, resulting in big underestimates of the population now at risk….41 million Americans live in the path of a once-in-a-century flood, rather than the 13 million indicated by existing maps. Meanwhile in Mozambique, hundreds have died since a cyclone’s torrential rain flooded more than 2000 square kilometers. Scientists recently reported progress in using high-resolution satellite data and enhanced computing power to create global flood models; these could improve emergency flood warnings and long-term planning in Mozambique and other developing countries that lack these tools.

Rapid Apple Decline Has Researchers Stumped

[These excerpts are from an article by Erik Stokstad in the 22 March 2019 issue of Science.]

      Six years ago, an unpleasant surprise greeted plant pathologist Kari Peter as she inspected a research orchard in Pennsylvania. Young apple trees were dying—and rapidly. At first, she suspected a common pathogen, but chemical treatments didn’t help. The next year, she began to hear reports of sudden deaths from across the United States and Canada. In North Carolina, up to 80% of orchards have shown suspicious symptoms….

      Now, as their trees prepare to blossom, North America’s apple producers are bracing for new losses, and scientists are probing possible causes. Apples are one of the continent’s most valuable fruit crops, worth some $4 billion last year in the United States alone. Growers are eager to understand whether rapid or sudden apple decline, as it is known, poses a serious new threat to the industry.

      Weather-related stress—drought and se-vere cold—could be an underlying cause….Early freezes are becoming more common across the eastern United States, for example. But that doesn’t appear to be the whole story, and scientists are examining an array of other factors, including pests, pathogens, and the growing use of high-density orchards….

      One common symptom in trees struck by rapid decline is dead tissue at the graft union, the part of the trunk where the fruit-bearing budwood of an apple variety is joined to hardy rootstock to create new trees. The union is vulnerable to late-season freezes because the tissue is the last to go dormant.

      A team led by plant pathologist Awais Khan of Cornell found dead tissue just below the graft union in trees from an affected orchard in New York. They suspect the cause was the extremely cold winter of 2014-15, which was followed by a drought. The dying tissue could have weakened the trees, allowing pests or pathogens to invade. But Khan and colleagues could not locate any known culprits in the affected trees or nearby soil….

      Observations from other apple-growing regions suggest extreme weather isn’t entirely to blame. In Canada, rapid decline “exploded” in British Columbia in the summer of 2018, after a string of unusually mild winters….These orchards are irrigated, suggesting drought was not a factor.

      Some scientists wonder whether certain rootstocks or exposure to herbicides might make trees more susceptible. Decline seems to be more common in trees with a popular rootstock, called M9, which can be slower to dormant in fall….decline appears to be more common in orchards with fewer weeds, leading him to suspect herbicides play a role.

      Meanwhile, the search for new pathogens is accelerating….But getting an answer could take up to 5 years….

      In hard-hit North Carolina, researchers 1 have found ambrosia beetles infesting the graft union of dying trees. These stubby insects burrow into weakened trees and cultivate fungus for their larvae to eat. Those fungi or stowaway fungi might harm the trees….

      Modern apple farming methods could also be a factor. Rapid decline is most common in dense orchards, which are increasingly planted because they are efficient to manage. Instead of about 250 trees per hectare, high-density orchards can have 1200 or more. Tightly packed trees must compete for nutrition and moisture. They also have shallow roots, which make them easier to trellis but more vulnerable to drought….

The Need to Catalyze Changes in High School Mathematics

[These excerpts are from an article by Robert Q. Berry III and Mathew R. Larson in the March 2019 issue of Phi Delta Kappan.]

      In the last few decades, policy makers and reformers have described the goal of boosting students’ college and career readiness (and, by extension, preparing those students to contribute to national defense and economic prosperity) as more or less the only purpose for learning high school mathematics, while other purposes, such as teaching students to think critically and participate actively in civic life, have been given short shrift….But in fact, mathematics can serve multiple purposes, and should be taught in ways that prepare students to “flourish as human beings….”

      Mathematics underlies much of the fabric of society, from polling and data mining in politics, to algorithms used in targeting advertisements, to complex mathematical models of financial instruments and policies that affect the lives of millions of people. Students should leave high school with the quantitative literacy and critical-thinking processes necessary to determine the validity of claims made in scientific, economic, social, and political arenas….Students should have an appreciation for the beauty and usefulness of mathematics and statistics. And students should see themselves as capable lifelong learners and confident doers of mathematics and statistics….

      Mathematics education at the high school level is part of a complex system of policies, traditions, and societal expectations. This system and its structures (school district policies, practices, and conditions) must be critically examined, changed, and improved. All stakeholders — school, district, and state administrators; instructional leaders and coaches; classroom teachers; counselors; curriculum and assessment developers; higher education administration and faculty, and policy makers at all levels — will need to be part of the process of reexamining long-standing beliefs, practices, and policies. This work is critical for all of us to undertake. It is also long overdue.

      Francis Su, past president of the Mathematical Association of America, has argued that answering the “why we teach mathematics” question is critical because the answer will have a strong influence on who we think should learn math-ematics and how we think mathematics should be taught….The work of making this happen will not be easy because the challenges are real and long-standing. But we owe this effort not only to our students but also to ourselves as we work together to create and nurture the society we wish to inhabit.

Standards, Instructional Objectives, and Curriculum Design: A Complex Relationship

[These excerpts are from an article by David A. Gamson, Sarah Anne Eckert, and Jeremy Anderson in the March 2019 issue of Phi Delta Kappan.]

      Since the formation of the American republic and the nation’s first halting steps toward building state public school systems, educators and policy makers have debated which kinds of knowledge and skills schoolchildren should acquire and the levels of proficiency they should reach. Today, we often call these expectations standards, and the most recent effort at defining these types of academic objectives is the Common Core State Standards, an outgrowth of the standards-based reform movement that has been with us now for a quarter century, with no signs of dissipating. For instance, the most recent reauthorization of the Elementary and Secondary Education Act — the 2015 Every Student Succeeds Act — reinforces the movement by requiring “that all students in America be taught to high academic standards that will prepare them to succeed in college and careers.”

      The vocabulary used to describe what students should know and be able to do when they complete a lesson, a unit, or course has shifted over the past 100 years, but the underlying belief in the necessity of standards has not…. /p>

      The origins of the current standards-based reform movement are usually pegged to events of the late 1980s and early 1990s, when state legislatures and governors began to assert a new level of authority over the details of student learning. But while these developments marked an important shift in reform strategy, the obsession with standards in our national educational experience actually goes back much further. Over the past century, policy makers have made many efforts to specify the learning objectives toward which the K-12 curriculum should lead.

      Beginning in the 1890s, and with greater regularity than most scholars have recognized, prominent educational leaders dedicated themselves to identifying the core curricular material necessary for American students to thrive in and out of school. The first major national undertaking, sponsored by the National Education Association (NEA), was the Committee of Ten’s (1893) attempt to determine what knowledge high school pupils require.

      The Committee of Ten was successful in sketching out core curricular requirements, such as five weekly periods of Latin each year in grades 9-12, five weekly periods of chemistry in grade 11, and one year of natural history (botany, zoology, etc.) at some point during high school. At the same time, though, its recommendations grated against the zeitgeist of the times. Many progressives thought the notion of a common curriculum for all students was hopelessly anachronistic in an era in when pupils could (or should) be scientifically sorted using IQ tests and divided into separate tracks of coursework. Moreover, young educators and reformers wanted to escape the rigidity that characterized their experience with the 19th-century curriculum….

      In virtually every period of American educational history, but especially in times of national crisis, critics have argued that American students were floundering academically due to intellectually feeble and flabby academic objectives….

      That assertion was repeated in 1958 after the Soviets launched Sputnik (and again in the 1980s and 1990s after states had been shocked into action by A Nation at Risk). Critics of public schools in the 1950s argued that schools had become “educational wastelands” and so often forsook fundamentals that “Johnny” couldn’t read. A Life magazine series (1958) argued that standards had become “shockingly low” and documented examples of failure within public schools, in part by contrasting the rigor of Soviet schools with the weak academics and leisure-oriented offerings of their American counterparts. Other developments of the time, including the work of educational scholars, reinforced the quest for strong and clear objectives….

      One vocal critic of an overreliance on objectives or other predetermined “ends” of education was Elliott Eisner (1967), who explained that “the outcomes of education are far more numerous and complex for educational objectives to encompass”….He believed that curricula driven by predetermined outcomes prohibited the development of “curiosity, inventiveness, and insight”….In other words, heavy reliance on objectives in curriculum design not only eliminated the potential for unanticipated learnings, but also had the potential to limit the development of creativity and critical thinking in students — which, to Eisner, were the true goals of schooling.

      …Behavioral objectives, argued Ebel, rarely match the real intent of instruction. Furthermore, simply stating an objective in behavioral terms does not inherently make it worth striving for. For example, it is quite difficult to specify an observable outcome when the intent of instruction is for students “to respond adaptively and effectively to unique future problem situations”…, and clearly stating that a child should be able to name all of the rivers in South America doesn’t necessarily make this a worthwhile skill….

      …In part because clearly articulating and measuring higher-level thinking skills was more difficult, only a handful of states adopted such standards for all students….

      For well over a century, educational leaders and policy makers have turned to standards as a kind of safety zone, a common ground whereupon (they hoped) all educators could meet and agree on dear, consistent, and rationally developed objectives. Americans find comfort in knowing precisely what students should know and be able to do, especially at times of national uncertainty or economic transition — whether represented by World War I, the Great Depression, the Space Race, or anxiety about global competitiveness. Even skeptics of standards acknowledge that some skills are amenable to concise articulation and demonstrable achievement and that some proficiencies can be measured; their main concern is with universal adoption of standards as the primary tool for curriculum development.

      Nevertheless, American educators have trod this terrain before, as it turns out, and we would do well to listen to the echoes of previous experiences. Several enduring dilemmas are posed by the persistent desire for measurable objectives, and policy makers and practitioners can benefit from the lessons gleaned by a close reading of the educational past. Aside from the controversies that will attend the development of any new learning goals, policy makers must acknowledge the constraints that standards are likely to place on classroom instruction.

      More specifically, state and local leaders will need to remain watchful of the riptide of confusion and consternation that will follow on the publication of large, potentially overwhelming, lists of objectives. Whether standards can be unpacked and translated into realistic and vibrant classroom activities will depend on the support and resources made available to teachers. Otherwise, the aims of academic disciplines and the knowledge embedded within core subject areas will all too easily be shattered into the thin, disconnected shards of minor objectives, which in turn will ultimately narrow any broader vision of education….

      The history of reform movements demonstrates that one reform regime is often pushed aside by a wave of novel educational innovations. Whether the standards-based reform movement can regularly upgrade itself enough to escape such a fate remains to be seen. Finally, then, persists the danger that Bode once voiced about Bobbin’s objectives: Standards that stagnate, drifting on unrevised or unevolved, will do more to perpetuate the status quo rather than to prepare students for the future. In an increasingly unequal society, that hazard is well worth avoiding.

Zombie Spiders

[These excerpts are from an article by Joshua Rapp Learn in the March 2019 issue of Scientifi American.]

      Talk about a raw deal: deadly parasitic wasps ruin the lives of adolescent spiders by taking over their minds, forcing them to become hermits and then eating them alive.

      A remarkable species of social spider lives in parts of Latin America, in colonies of thousands. Anelosimus eximius spiders dwell in basket-shaped webs up to 25 feet wide attached to vegetation near the jungle floor, where they protect their eggs and raise broods cooperatively. A colony works together to take down much larger prey, such as grasshoppers, which sometimes fall into a web after blundering into silk lines L that stick out of it vertically….

      But Fernandez-Fournier recently observed a wasp species—not previously named or described in the scientific literature—that can bend these social spiders to its will in an even more nightmarish way. This parasitic puppet master camps out beside the web, apparently waiting for a young spider to stray from its colony. The wasp may prefer juveniles because of their softer shells and “less feisty” nature….

      Scientists do not know how a wasp larva ends up on the spider—but once there it starts feeding on the arachnid’s abdomen. As the larva grows, it starts to control the spider’s brain, inducing it to leave the safety of its colony. Then the young spider weaves a ball of silk that seals it off from the outside world. The larva completes its life cycle by eating the rest of the spider, using the conveniently surrounding web to build its own cocoon and pupate into an adult wasp.

      Fernandez-Fournier believes the wasp larvae most likely release a chemical that activates specific genes in their hosts, triggering antisocial behavior. Other related spiders are less social, leaving their colonies when they are young….the mind-controlling wasp larvae may be tapping into this latent genetic pathway. The spiders may have evolved toward social living for protection from predators, but the parasites could be pulling the genetic strings in their favor….

Feverish Planet

[These excerpts are from an article by Tanya Lewis in the March 2019 issue of Scientific American.]

      A devastating heat wave swept across Europe in 2003, killing tens of thousands of people, scientists estimate. Many were elderly, with limited mobility, and some already suffered from chronic diseases. But climate change is making such extreme weather more common—and the effects will not be limited to the old and sick. Warming temperatures do not only threaten lives directly. They also cause billions of hours of lost labor, enhance conditions for the spread of infectious diseases and reduce crop yields, according to a recent report….

      The report found that millions of people worldwide are vulnerable to heat-related disease and death and that populations in Europe and the eastern Mediterranean are especially susceptible—most likely because they have more elderly people living in urban areas. Adults older than 65 are particularly at risk, as are those with chronic illnesses such as heart disease or diabetes. Places where humans tend to live are exposed to an average temperature change that is more than twice the global L L average-0.8 versus 0.3 degree Celsius….

      Sweltering temperatures also affect productivity. A staggering 153 billion hours of labor—80 percent of them in agriculture—were lost to excessive heat in 2017, the new report found, with the most vulnerable areas being in India, Southeast Asia, sub-Saharan Africa and South America. The first stage of heat’s impact is discomfort….But there comes a point at which it is simply too hot for the body to function. For example, sweating heavily without replenishing water can result in chronic kidney disease….News reports have documented - farm workers in Central America dying from kidney problems afteryears of working in the hot fields. Richer countries such as the U.S. may avoid the worst effects because of better access to drinking water and, in the case of indoor work, air-conditioning. But these solutions can be expensive….

      Climate change also threatens food security. Our planet still produces more than enough food for the world, but 30 countries have seen crop yields decline as a result of extreme weather….

      Among the biggest steps countries can take to mitigate these health effects are phasing out coal-fired power and shifting to greener forms of transportation….Electric vehicles are making inroads in places…and “active” transport, such as walking or cycling, is also important….

The Weather Amplifier

[These excerpts are from an article by Michael E. Mann in the March 2019 issue of Scientific American.]

      Consider the following summer extremes: In 2003 Europe’s worst heat wave in history killed more than 30,000 citizens. In 2010 wildfires in Russia and floods in Pakistan caused unprecedented damage and death. The 2011 U.S. heat wave and drought caused rarchers in Oklahoma to lose a quarter of their cattle. The 2016 Alberta wildfires constituted the costliest disaster in Canadian history. And the summer of 2018 that the U.S. experienced the notorious: temperatures flared above 100 degrees Fahrenheit for days on end across the desert Southwest, heavy rains and floods inundated the mid-Atlntic states, and California had a shocking wildfire season. Extreme heat waves, floods and wildfires raged across Europe and Asia, too.

      …All these events had a striking feature in common: a very unusual pattern in the jet stream. The jet stream is a narrow band of strong wind that blows west to east around the Northern Hemisphere, generally along the U.S.-Canada border, continuing across the Atlantic Ocean, Europe and Asia. The band is sometimes fairly straight, but it can take on big bends—shaped like an S lying on its side. It typically curls northward from the Pacific Ocean into western Canada, then turns southward across the U.S. Midwest, then back up toward Nova Scotia. This shape usually proceeds west to east across the U.S. hi a few days, bringing warm air north or cool air south and creating areas of rain or snow, especially near the bends. The jet stream controls our daily weather.

      During the extreme events I noted, the jet stream acted strangely. The bends went exceptionally far north and south, and they stalled—they did not progress eastward. The larger these bends, the more punishing the weather gets near the northern peak and southern trough. And when they stall—as they did over the U.S. in the summer of 2018—those regions can receive heavy rain day after day or get baked by the sun day after day. Record floods, droughts, heat waves and wildfires occur….

Don’t Let Bots Pull the Trigger

[These excerpts are from an editorial by the editors of the March 2019 issue of Scientific American.]

      The killer machines are coming. Robotic weapons that target and destroy without human supervision are poised to start a revolution in warfare comparable to the invention of gunpowder or the atomic bomb. The prospect poses a dire threat to civilians—and could lead to some of the bleakest scenarios in which artificial intelligence runs amok. A prohibition on killer robots, akin to bans on chemical and biological weapons, is badly needed. But some major military powers oppose it.

      The robots are no technophobic fantasy. In July 2017, for example, Russia’s Kalashnikov Group announced that it had begun development of a camera-equipped 7.62-millimeter machine gun that uses a neural network to make “shoot/no-shoot” decisions. An entire generation of self-controlled armaments, including drones, ships and tanks, is edging toward varying levels of autonomous operation. The U.S. appears to hold a lead in R&D on autonomous systems—with $18 billion slated for investment from 2016 to 2020. But other countries with substantial arms industries are also making their own investments.

      …The inability to read behavioral subtleties to distinguish civilian from combatant or friend versus foe should call into question whether AIs should replace GIs in a foreseeable future mission. A killer robot of any kind would be a trained assassin, not unlike Arnold Schwarzenegger in The Terminator. After the battle is done, moreover, who would be held responsible when a machine does the killing? The robot? Its owner? Its maker?

      With all these drawbacks, a fully autonomous robot fashioned using near-term technology could create a novel threat wielded by smaller nations or terrorists with scant expertise or financial resources. Swarms of tiny, weaponized drones, perhaps even made using 3-D printers, could wreak havoc in densely populated areas. Prototypes are already being tested: the U.S. Department of Defense demonstrated a nonweaponized swarm of more than 100 micro drones in 2016….

      …Because of opposition from the U.S., Russia and a few others, the discussions have not advanced to the stage of drafting formal language for a ban. The U.S., for one, has argued that its policy already stipulates that military personnel retain control over autonomous weapons and that premature regulation could put a damper on vital Al research.

      A ban need not be overly restrictive. The Campaign to Stop Killer Robots, a coalition of 89 nongovernmental organizations from 50 countries that has pressed for such a prohibition, emphasizes that it would be limited to offensive weaponry and not extend to antimissile and other defensive systems that automatically fire in response to an incoming warhead….

      Since it was first presented at the International Joint Conference on Artificial Intelligence in Stockholm in July, 244 organizations and 3,187 individuals have signed a pledge to “neither participate in nor support the development, manufacture, trade, or use of lethal autonomous weapons.” The rationale for making such a pledge was that laws had yet to be passed to bar killer robots. Without such a legal framework, the day may soon come when an algorithm makes the fateful decision to take a human life.

Nowhere to Hide

[These excerpts are from an article by Amy Yee in the 15 March 2019 issue of Science.]

      The small pangolin tucked its head toward its belly and curled its tail around its body. Clad in large scales, it resembled a pine cone. After a moment, the creature—a mammal, despite appearances—uncoiled and raised its slender head. Currantlike eyes blinked and a pointy nose trembled inquisitively. Its feet had tender pink soles tipped with long, curved claws, but it did not scratch or fight.

      This animal, a white-bellied pangolin (Phataginus tricuspis), was lucky. It had most likely been illegally caught in a nearby forest not long ago; a tip had led the Uganda Wildlife Authority (UWA) to rescue it. One of its brown scales had been ripped off, perhaps for use in a local witchcraft remedy. But after a long, jarring car ride on bumpy dirt roads, the pangolin was being released back into the wild in a national park….Weighing just 2.5 kilograms, the pangolin heaved as if panting.

      The rescue and release was part of a growing global effort to save pangolins which face a bleak future as the world’s most poached and trafficked animal. They are in demand for both their meat and their scales, believed in some Asian countries to have medicinal properties. The past 2 months have seen record-setting seizures of pangolin body parts both in Asia and Africa….

      In 2014, the International Union for Conservation of Nature (IUCN) classified all eight pangolin species—four of which live in Asia and four in Africa—as threatened with extinction. And in 2017, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) banned international trade in pangolins. Several groups and government agencies, including UWA, are now intensifying conservation efforts both in Asia and Africa.

      Yet it’s an uphill battle. Large endangered wildlife, such as elephants and rhinos, attract tourist dollars, giving policymakers an incentive to save them. But pangolins are small, shy, and believed to be mostly nocturnal. Patchy understanding of their population size, breeding behavior, migratory patterns, and physiology also hampers conservation efforts….

      Pangolins are unique among mammals because of their scales, which are made of keratin, the stuff of hair and fingernails. They live on a diet of ants and termites—hence their nickname “scaly anteater.” The scales are their major defense mechanism; when faced with danger, they curl up in an immobile, hard ball. Sadly, that also makes them easy for hunters and poachers to catch.

      Pangolins have long been on the menu for people in Asia and Africa. According to a 2018 study, 400,000 to 2.7 million pangolins are hunted annually in the forests of six Central African countries for bushmeat. (The range is so wide because researchers used three different ways of estimating the harvest, says the paper's first author, Daniel Ingram of University College London, but the lower figure is more likely.)

      Demand for pangolin scales seems to be surging, particularly in China and Vietnam, where they are believed to cure ailments ranging from poor circulation and skin diseases to asthma. With Asian species in sharp decline, poachers are increasingly turning to Africa for scales, adding to the ushmeat toll….

      Pangolins are slow-breeding and give birth to one offspring a year at most, which means depleted populations are slow to bounce back. They are easily stressed and tend to die in captivity; which makes studying their physiology and behavior difficult. So far, efforts to breed them have largely failed. Biologists also know little about their movements and population sizes, which Lould guide efforts to protect them….

The Meat without the Cow

[These excerpts are from an article by Niall Firth in the March/April 2019 issue of Technology Review.]

      …A little over five years later, startups around the world are racing to produce lab-grown meat that tastes as good as the traditional kind and costs about as much.

      They’re already playing catch-up: “plant-based” meat, made of a mix of non-animal products that mimic the taste and texture of real meat, is already on the market. The biggest name in this area: Impossible Foods, whose faux meat sells in more than 5,000 restaurants and fast food chains in the US and Asia and should be in supermarkets later this year. Impossible’s research team of more than 100 scientists and engineers uses techniques such as gas chromatography and mass spectrometry to identify the volatile mole-cules released when meat is cooked.

      The key to their particular formula is the oxygen-carrying molecule heme, which contains iron that gives meat its color and metallic tang. Instead of using meat, Impossible uses genetically modified yeast to make a version of heme that is found in the roots of certain plants.

      Impossible has a few competitors, particularly Beyond Meat, which uses pea protein (among other ingredients) to replicate ground beef. Its product is sold in supermarket chains like Tesco in the UK and Whole Foods in the US, alongside real meat and chicken. Both Impossible and Beyond released new, improved versions of their burgers in mid-January.

      In contrast, none of the lab-grown-meat start-ups has yet announced a launch date for its first commercial product. But when that happens—some claim as early as the end of this year—the lab-grown approach could turn the traditional meat industry on its head.

      …The answer is that our meat consumption habits are, in a very literal sense, not sustainable. Livestock raised for food already contribute about 15% of the world's global greenhouse-gas emissions. (You may have heard that if cows were a country, it would be the world's third biggest emitter.) A quarter of the planet’s ice-free land is used to graze them, and a third of all cropland is used to grow food for them. A growing population will make things worse. It’s estimated that with the population expected to rise to 10 billion, humans will eat 70% more meat by 2050. Greenhouse gases from food production will rise by as much as 92%.

      In January a commission of 37 scientists reported in The Lancet that meat’s damaging effects not only on the environment but also on our health make it “a global risk to people and the planet.” In October 2018 a study in Nature found that we will need to change our diets significantly if we’re not to irreparably wreck our planet’s natural resources….

      The good news is that a growing number of people now seem to be rethinking what they eat. A recent report from Nielsen found that sales of plant-based foods intended to replace animal products were up 20% in 2018 compared with a year earlier. Veganism, which eschews not just meat but products that come from greenhouse-gas-emitting dairy livestock too, is now considered relatively mainstream.

      That doesn’t necessarily equate to more vegans. A recent Gallup poll found that the number of people in the US who say they are vegan has barely changed since 2012 and stands at around just 3%. Regardless, Americans are eating less meat, even if they're not cutting it out altogether….

      The traditional meat industry doesn’t see it that way. The National Cattlemen's Beef Association in the US dismissively dubs these new approaches “fake meat.” In August 2018, Missouri enacted a law that bans labeling any such alternative products as meat. Only food that has been “derived from harvested production of livestock or poultry” can have the word “meat” on the label in any form. Breaking that law could lead to a fine or even a year’s jail time.

      The alternative-meat industry is fighting back….to get the law overturned….

      …But the Missouri battle is just the start of a struggle that could last years. In February 2018, the US Cattlemen's Association launched a petition that calls on the US Department of Agriculture (USDA) to enact a similar federal law.

      Traditional meat-industry groups have also been very vocal on how cultured meat and plant-based meats are to be regulated….

      But there are other issues, says Datar, of New Harvest. She says we still don’t understand the fundamental processes well enough. While we have quite a deep understanding of animals used in medical research, such as lab mice, our knowledge of agricultural animals at a cellular level is rather thin….

      Lab-grown meat has another—more tangible—problem. Growing muscle cells from scratch creates pure meat tissue, but the result lacks a vital component of any burger or steak: fat. Fat is what gives meat its flavor and moisture, and its texture is hard to replicate. Plant-based meats are already getting around the problem—to some extent—by using shear cell technology that forces the plant protein mixture into layers to produce a fibrous meat-like texture. But if you want to create a meat-free “steak” from scratch, some more work needs to be done. Cultured meat will need a way to grow fat cells and somehow mesh them with the muscle cells for the end result to be palatable. That has proved tricky so far, which is the main rea-son that first burger was so mouth-puckeringly dry….

      As it stands, lab-grown meat is not quite as virtuous as you might think. While its greenhouse emissions: are below those associated with the biggest villain, beef, it is more polluting than chicken or the plant-based alternatives, because of the energy currently:- required to produce it. A World Economic Forum white paper on the impact of alternative meats found that lab-grown meat as it is made now would produce only about 7% less in greenhouse-gas emissions than beef. Other replacements, such as tofu or plants, pro-duced reductions of up to 25%....

      Expecting the whole world to go vegan is unrealistic. But a report in Nature in October 2018 suggested that if everyone moved to the flexitarian lifestyle (eating mostly vegetarian but with a little poultry and fish and no more than one portion of red meat a week), we could halve the greenhouse-gas emissions from food production and also reduce other harmful effects of the meat industry, such as the overuse of fertilizers and the waste of fresh water and land. (It could also reduce premature mortality by about 20%, according to a study in The Lancet in October, thanks to fewer deaths from ailments such as coronary heart disease, stroke, and cancer.)…

Is Carbon Removal Crazy or Critical?

[These excerpts are from an article by Spencer Lowell in the March/April 2019 issue of Technology Review.]

      …Lackner…has now been working on the problem for two decades. In 1999, as a particle physicist at Los Alamos National Laboratory, he wrote the first scientific paper exploring the feasibility of combating climate change by pulling carbon dioxide out of the air. His was a lonely voice for years. But a growing crowd has come around to his thinking as the world struggles to slash climate emissions fast enough to prevent catastrophic warming. Lackner’s work has helped inspire a handful of direct-air-capture startups, including one of his own, and a growing body of scientific literature….

      No one, including Lackner, really knows whether the scheme will work. The chemistry is easy enough. But can we really construct anywhere near enough carbon removal machines to make a dent in climate change? Who will pay for them? And what are we going to do with all the carbon dioxide they collect?

      Lackner readily acknowledges the unknowns but believes that the cheaper the process gets, the more feasible it becomes….

      The concentration of carbon dioxide in the atmosphere is approaching parts per million. That has already driven global temperatures nearly 1 °C above pre-industrial levels and intensified droughts, wildfires, and other natural disasters. Those dangers will only compound as emissions continue to rise. /p>

      The latest assessment from the UN’s Intergovernmental Panel on Climate Change found that there’s no way to limit or return global warming to 1.5 °C without removing somewhere between 100 billion and a trillion metric tons of carbon dioxide by the end of the century. On the high end, that means reversing nearly three decades of global emissions at the current rate.

      There are a handful of ways to draw carbon dioxide out of the atmosphere. They include planting lots of trees, restoring grasslands and other areas that naturally hold carbon in soils, and using carbon dioxide-sucking plants and other forms of biomass as a fuel source but capturing any emissions when they’re used (a process known as bio-energy with carbon capture and storage).

      But a report from the US National Academies in October found that these approaches alone probably won’t be enough to prevent 2 °C of warming—at least, not if we want to eat. That's because the amount of land required to capture that much carbon dioxide would come at the cost of a huge amount of agricultural food production.

      The appeal of direct-air-capture devices like the ones Lackner and others are developing is that they can suck out the same amount of carbon dioxide on far less land. The big problem is that right now it’s much cheaper to plant a tree. At the current cost of around $600 per ton, capturing a trillion tons would run some $600 trillion, more than seven times the world's annual GDP….

      However, selling carbon dioxide isn’t an easy proposition.

      Global demand is relatively small: on the order of a few hundred million tons per year, a fraction of the tens of billions that eventually need to be removed annually, according to the National Academies study. Moreover, most of that demand is for enhanced oil recovery, a technique that forces compressed carbon dioxide into wells to free up the last drips of oil, which only makes the climate problem worse….

How We’ll Invent the Future

[These excerpts are from an article by Bill Gates in the March/April 2019 issue of Technology Review.]

      …My mind went to—of all things—the plow. Plows are an excellent embodiment of the history of innovation. Humans have been using them since 4000 BCE, when Mesopotamian farmers aerated soil with sharpened sticks. We’ve been slowly tinkering with and improving them ever since, and today’s plows are technological marvels.

      But what exactly is the purpose of a plow? It’s a tool that creates more: more seeds planted, more crops harvested, more food to go around. In places where nutrition is hard to come by, it’s no exaggeration to say that a plow gives people more years of life. The plow—like many technologies, both ancient and modern—is about creating more of something and doing it more efficiently, so that more people can benefit.

      Contrast that with lab-grown meat, one of the innovations I picked for this year’s 10 Breakthrough Technologies list. Growing animal protein in a lab isn’t about feeding more people. There’s enough livestock to feed the world already, even as demand for meat goes up. Next-generation protein isn’t about creating more — it’s about making meat better. It lets us provide for a growing and wealthier world without contributing to deforestation or emitting methane. It also allows us to enjoy hamburgers without killing any animals.

      Put another way, the plow improves our quantity of life, and lab-grown meat improves our quality of life. For most of human history, we’ve put most of our innovative capacity into the formetAnd our efforts have paid off: world-wide life expectancy rose from 34 years in 1913 to 60 in 1973 and has reached 71 today….

      To be clear, I don’t thinkhuman-ity will stop trying spans anytime soon. We’re still far from a world where everyone everywhere lives to old age in perfect health, and it’s going to take a lot of innovation to get us there. Plus, “quantity of life” and “quality of life” are not mutually exclusive. A malaria vaccine would both save lives and make life better for children who might otherwise have been left with developmental delays from the disease.

      We’ve reached a point where we’re tackling both ideas at once, and that’s what makes this moment in history so interesting….

      The 30 minutes you used to spend reading e-mail could be spent doing other things. I know some people would use that time to get more work done—but I hope most would use it for pursuits like connecting with a friend over coffee, helping your child with homework, or even volunteering in your community.

      That, I think, is a future worth working toward.

Sanitation without Sewers

[These excerpts are from an article by Erin Winick in the March/April 2019 issue of Technology Review.]

      About 2.3 billion people don’t have good sanitation. The lack of proper toilets encourages people to dump fecal matter into nearby ponds and streams, spreading bacteria, viruses, and parasites that can cause diarrhea and cholera. Diarrhea causes one in nine child deaths worldwide.

      Now researchers are working to build a new kind of toilet that’s cheap enough for the developing world and can not only dispose of waste but treat it as well….

      Most of the prototypes are self-contained and don’t need sewers, but they look like traditional toilets housed in small buildings or storage containers. The NEWgenerator toilet, designed at the University of South Florida, filters out pollutants with an anaerobic membrane, which has pores smaller than bacteria and viruses. Another project, from Connecticut-based Biomass Controls, is a refinery the size of a shipping container; it heats the waste to produce a carbon-rich material that can, among other things, fertilize soil….

      So the challenge now is to and more adaptable to communities of different sizes….

The Cow-free Burger

[These excerpts are from an article by Markkus Rovito in the March/April 2019 issue of Technology Review.]

      The UN expects the world to have 9.8 billion people by 2050. And those people are getting richer. Neither trend bodes well for climate change—especially because as people escape poverty, they tend to eat more meat.

      By that date, according to the predictions, humans will consume 70% more meat than they did in 2005. And it turns out that raising animals for human consumption is among the worst things we do to the environment.

      Depending on the animal, producing a pound of meat protein with Western methods requires 4 to 25 times more water, 6 to 17 times more land, and 6 to 20 times more fossil fuels than producing a pound of plant protein.

      The problem is that people aren’t likely to stop eating meat anytime soon. Which means lab-grown and plant-based alternatives might be the best way to limit the destruction.

      Making lab-grown meat involves extracting muscle tissue from animals and growing it in bioreactors. The end product looks much like what you’d get from an animal, although researchers are still working Lon the taste….One drawback 1 of lab-grown meat is that the environmental benefits are still sketchy at best—a recent World Economic Forum report says the emissions from lab-grown meat would be only around 7% less than emissions from beef production.

      The better environmental case can be made for plant-based meats from companies like Beyond Meat and Impossible Foods (Bill Gates is an investor in both companies), which use pea proteins, soy, wheat, potatoes, and plant oils to mimic the texture and taste of animal meat….a Beyond Meat patty would probably generate 90% less greenhouse-gas emissions than a conventional burger made from a cow.

Sun in a Box

[These excerpts are from an article by Jennifer Chu in the March/April 2019 issue of MIT News.]

      MIT engineers have come up with a conceptual design fora system that could store renewable energy and deliver it back into an electric grid on demand. Such a system could power a small city not just when the sun is up or the wind is high, but around the clock.

      The new design stores heat generated by excess electricity from solar or wind power in large tanks of molten silicon, and then converts the light from the glowing metal back into electricity when it’s needed. The researchers expect it would be vastly more affordable than lithium-ion storage systems.

      The system consists of two large, heavily insulated, 10-meter-wide tanks made from graphite. One is filled with liquid silicon, kept at a “cold” temperature of almost 3,500 °F (1,927 °C). A bank of tubes, exposed to heating elements, then connects this cold tank to the second, “hot” tank. When electricity from the town’s solar cells comes into the system, this energy is converted to heat in the heating elements. Meanwhile, liquid silicon is pumped out of the cold tank, collects heat from the heating elements as it passes through the tubes, and enters the hot tank, where it is now stored at a much higher temperature of about 4,300 °F (2,371 °C).

      When electricity is needed (say, after the sun has set), the hot liquid silicon—so hot that it’s glowing white—is pumped through an array of tubes that emit that light. Specialized solar cells, known as multi-junction photovoltaics, then turn that light into electricity, which can be supplied to the town’s grid. The now-cooled silicon can be pumped back into the cold tank until the next round of storage—so the system effectively acts as a large rechargeable battery….

      Henry says the system could be sited anywhere, regardless of a location's landscape. This is in contrast to pumped hydroelectric systems, currently the cheapest form of energy storage, which require locations that can accommodate large waterfalls and dams to store energy from falling water….

The Climate Optimist

[These excerpts are from an article by Amanda Schaffer in the March/April 2019 issue of MIT News.]

      …the data she gathered that night and over two months in Antarctica would change our understanding of how chlorofluorocarbons, released into the atmosphere from refrigerants and a range of other consumer products, damage the ozone layer, which helps protect Earth from ultraviolet radiation. In response to this and other scientific work, an international agreement limited and then banned the use of CFCs. Thirty years later, [Susan] Solomon was also the first to clearly demonstrate that, thanks to this change, the Antarctic ozone hole has slowly begun to heal….

      Solomon is quick to acknowledge that climate change poses tougher political challenges than ozone depletion, because fossil-fuel consumption is so integral to the world economy. Still, she argues that by studying past environmental successes, her students will come to understand “what is actually going to have to happen to make progress….”

      The spectral data that Solomonl and her team gathered provided support for the theory that chlorine originally locked up in chlorofluorocarbons is released by way of a surface reaction between hydrochloric acid and chlorine nitrate on polar stratospheric clouds. That chlorine in turn reacts with ozone to produce chlorine monoxide and goes on to deplete the ozone. Further buttressing her theory, Solomon’s expedition found that stratospheric concentrations of hydrochloric acid were low and those of chlorine monoxide and chlorine dioxide were high. (They also used balloons to measure concentrations of ozone directly and found that it, too, was severely depleted in the stratosphere, as expected.)….

      In her role on the IPCC report, Solomon worked with some 150 of the best climate scientists in the world, helping to synthesize current research related to climate change. Finding areas of consensus required a mix of science and diplomacy…."

      In 2007, the group produced a textbook-size tome, which Solomon keeps above her desk, and which garnered attention for stating, for the first time, that “warming is unequivocal.” (Solomon herself came up with that wording, based on the researchers' thorough examination of the research.) It also said that most of the warming of the past 50 years was “very likely due to human activity.” (The report defined “very likely” as meaning that the conclusion was 90% certain.) The year the report was published, the IPCC and former vice president Al Gore shared the Nobel Peace Prize for their efforts….

      In the years that followed, Solomon continued to work on climate change. In 2009, she published a paper showing that some of the effects of carbon dioxide, which takes a long time to dissipate from the atmosphere, are probably irreversible. Other researchers had conducted a set of experiments modeling where the carbon currently in the atmosphere would end up if emissions came to a halt. After examining this work, Solomon noticed that in all the models, Earth’s surface temperature did not significantly decrease for a thousand years, even in the absence of new carbon dioxide emissions. “On a human time scale, a thousand years is pretty close to irreversible,” she says. “I realized that that story had not been told clearly enough in a simple paper. I also wanted to understand why it was true.”

      She ultimately concluded that the key factor was the ocean, which is slow to warm but stores heat—and therefore warms the atmosphere—for long periods of time. In addition, her team found that even without further emissions of carbon dioxide, sea levels would also continue to rise for hundreds of years. And her lab at MIT would later reach a similar conclusion for even short-lived greenhouse gases like methane. Her research raises questions about whether vulnerable island nations and coastal populations can still be saved from the consequences of climate change….

      In other climate-related work, Solomon and her team explored how volcanic eruptions affect ozone depletion. In 2011, they found that even eruptions that appear to cause damage only at the local level can still fling enough sulfur into the stratosphere to put it into circulation there, where it can have global consequences….

      Recent news related to global climate change has been bleak—from the rapid rise in sea levels to catastrophic wildfires in California. The US government’s fourth National Climate Assessment, released by the Trump administration on the Friday of Thanksgiving weekend in 2018, warned that if significant steps are not taken to reduce emissions, the world will experience ever more dangerous heat waves, fires, floods, and hurricanes. These events are likely to cause crop failures, more frequent wildfires, and severe disruptions in supply chains and trade. Together, the changes could reduce the GDP of the United States alone 10% by 2100.

      But even in the face of dispiriting data, Solomon continues to focus on figuring out how to fix things. She tells her students that making headway on climate change depends on getting people to understand how the problem will affect them personally—and to believe there are practical solutions. And she’s hopeful about the progress she’s seeing.

      “Climate change won’t be solved until alternative energies become more widely adopted, but they are already becoming adopted at an incredibly astonishing pace,” she says. “Admittedly, it may not be as fast as it would need to be to hold temperatures to one and a half degrees—that would really be Herculean. But we can bend the warming curve.”

      Solomon notes that even though solar and wind power are not yet competitive in many parts of the United States, in many other places, clean-energy alternatives are becoming cheaper than fossil fuels. Certainly, there's a good deal more work to be done. Innovation must continue to bring down the costs of clean energy and improve the battery technology needed to store it. And the challenge of converting existing infrastructure to cleaner power sources will be massive….

More Screen Time, Lower Well-Being

[This brief newswothry item appeared in the February 2019 issue of Phi Delta Kappan.]

      A study published in Preventive Medicine Reports finds that as screen time goes up among children ages 2 to 17, psychological well-being goes down.

      Jean Twenge and W. Keith Campbell surveyed caregivers about the amount of time children in their care spent watching TV and videos, playing video games, and using computers and mobile devices for activities other than schoolwork. The survey also asked caregivers to respond to questions about children's emotional stability, relationships with caregivers, self-control, diagnoses of mood disorders, and mental health treatments.

      Screen time averaged 3.2 hours per day, with the amount of time going up as children get older. In general, young people spending up to an hour with screens had similar results on measures of psychological well-being as students who did not spend time with screens. However, once screen time reached more than an hour, and the more screen time increased beyond that, young people were rated lower on their ability to stay calm, finish tasks, learn new things, make friends, and avoid conflict with caregivers. In addition, children with higher levels of screen time were more likely to be diagnosed with anxiety and depression. The associations were largest among adolescents.

      The researchers note, however, that it is not clear from their study whether screen time leads to lower levels of well-being or whether lower levels of well-being leads to more screen time.

The Myth of de facto Segregation

[These excerpts are from an article by Richard Rothstein in the February 2019 issue of Phi Delta Kappan.]

      For nearly 30 years, the nation’s education policy makers have proceeded from the assumption that disadvantaged children would have much greater success in school if not for educators’ low expectations of them. In theory; more regular achievement testing and tougher accountability practices would force teachers to pursue higher academic standards for all children, resulting in improved instruction and greater student proficiency.

      However, there never was any evidence to support this theory, and even its most eager proponents have come to realize that it was flawed all along. In fact, there are a host of reasons why disadvantaged children often struggle to succeed academically. Undeniably, one is that some schools in low-income neighborhoods fall short in their traditional instructional roles. Another is that many schools have failed to embrace effective out-of-classroom programs —'such as health clinics or early childhood centers — that might enable students to be more successful in the classroom. Perhaps most important, however, is the influence of children’s out-of-school social and economic conditions, which predict academic outcomes to a far greater extent than what goes on in the classroom. Researchers have long known that only about one-third of the Black-White academic achievement gap results from variations in school quality. The rest stems from social and economic factors that render some children unable to take full advantage of what even the highest-quality schools can offer.

      Racial segregation exacerbates achievement gaps between Black and White children because it concentrates students with the most serious social and economic challenges in the same classrooms and schools. Consider childhood asthma, for example: Largely because of poorly maintained housing and environmental pollution, urban African-American children have asthma at as much as four times the rate of White middle-class children. Asthmatic children often come to school drowsy and inattentive from sleeplessness, or they don’t come to school at all. Indeed, asthma is the single most important cause of chronic absenteeism. No matter how good the teacher, or their instruction, children who are frequently absent will see less benefit than children who come to school well rested and regularly. Certainly, some asthmatic children will excel — there is a distribution of out-comes for every human condition — but on average, children in poorer health will fall short.

      Children from disadvantaged families suffer disproportionately from a number of other such problems, including lead poisoning that diminishes cognitive and behavioral capacity; toxic stress, from experiencing or witnessing violence; irregular sleep or meal times, related to their parents' working multiple jobs with contingent work schedules; housing instability or homelessness; parental incarceration, and many others. A teacher can give special attention to a few who come to school with challenges that impede learning, but if an entire class has such problems, average achievement inevitably declines.

      We cannot expect to address our most serious educational issues if the most disadvantaged of the nation’s children are concentrated in separate neighborhoods and schools. Today though, racial segregation characterizes every metropolitan area in the United States and bears responsibility for our most serious social and economic problems: Not only does it produce achievement gaps but it predicts lower life expectancies and higher disease rates for African Americans who reside in less healthy neighborhoods, and it corrupts our criminal justice system when police engage in violent altercations with young men who are concentrated in neighborhoods with inferior access to good jobs in the formal economy and without transportation to access those jobs (and for the same reason, segregation exacerbates economic inequality, too).

      Racial segregation also undermines our ability to succeed, economically and politically, as a diverse society. Some might argue that “a Black child does not have to sit next to a White child to learn.” They are wrong: Not only should Black children sit next to White children, but White children should sit next to Black children. A diverse adult society is inevitable; failing to prepare children for it invites disastrous conflict. This has become readily apparent, as our growing political polarization — which maps closely onto racial lines — threatens our very existence as a democratic society….

      …But if segregation has been created by government's explicit racial policies — that is, if residential segregation itself is a civil rights violation — then not only are we permitted to remedy it, we are required to do so.

      And we are so required. Not only did local police forces organize and support mob violence to drive Black families out of homes on the White side of racial boundaries, the federal government purposefully placed public housing in high-poverty, racially isolated neighborhoods to concentrate the Black population. It created a Whites-only mortgage insurance program to shift the White population from urban neighborhoods to exclusively White suburbs. The Internal Revenue Service granted tax exemptions to nonprofit institutions that openly sought neighborhood racial homogeneity. State government licensing agencies enforced a real estate brokers “code of ethics” that prohibited the sale of homes to African Americans in White neighborhoods. Federal and state regulators allowed the banking, thrift, and insurance industries to deny loans to homeowners in other-race communities.

      When the federal government first constructed civilian public housing during the Great Depression, it built separate projects for White and Black families, often segregating previously integrated communities. For instance, the great African-American poet, Langston Hughes, described in his autobiography how, in early-20th-century Cleveland, he went to an integrated neighborhood high school where his best friend was Polish and he dated a Jewish girl. However, the Public Works Administration — a federal agency created under the New Deal — demolished housing in that integrated neighborhood to build racially segregated public housing, creating residential patterns that persisted long into the future. This was the case even in places that today consider themselves racially progressive. In Cambridge, Mass., for example, the Central Square neighborhood between Harvard and the Massachusetts Institute of Technology was integrated in the 1930s, about half Black and half White. But the federal government razed integrated housing to create segregated projects that, with other projects elsewhere in the region, established a pattern of segregation throughout the Boston metropolitan area.

      During World War II, hundreds of thousands ofWhite and African-American migrants flocked to war plants in search of jobs, and federal agencies systematically segregated the war workers’ housing. In many cases, officials did so in places where few African Americans lived before the war and little previous pattern of segregation existed. Richmond, Calif., a suburb of Berkeley, was one such case. It was the largest shipbuilding center on the West Coast, employing 100,000 workers by war's end. In Berkeley, African-American workers were housed in separate buildings along the railroad tracks in an industrial area, while White workers were housed adjacent to a shopping area and White neighborhoods.

      Residents of even the most segregated communities couldn’t count on staying put, however. At the end of the war, local housing agencies in most parts of the country assumed responsibility for such projects and maintained their racial boundaries. However, Berkeley and the University of California (which owned some of the land on which war workers had been housed) refused to permit the public housing to remain, arguing not only that it would change the “character” of the community but also that the site wasn’t suitable for housing. The war projects were demolished and African-American residents were placed in public housing in Oakland. Then, the university reconsidered the site's suitability for housing and used the property for graduate student apartments.

      To be sure, some public officials fought against such policies and practices. In 1949, for instance, the U.S. Congress considered a proposal to prohibit racial discrimination in public housing. It was voted down, however, and federal agencies went on to cite this vote as justification for segregating all federal housing programs for at least another decade.

      Thus, during the years after World War II, the Federal Housing Administration (FHA) and Veterans Administration (VA) subsidized the development of entire subdivisions to house returning veterans and other working-class families on a Whites-only basis. Communities like Levittown (east of New York City), Lakewood (south of Los Angeles), and hundreds of others in between could be built only because the FHA and VA guaranteed the builders’ bank loans for purchase of land and construction of houses. The FHA's Underwriting Manual for appraisers who investigated applications for such suburbs required that projects could be approved only for “the same racial and social classes” and prohibited developments close enough to Black neighborhoods that they might risk “infiltration of inharmonious racial” groups….

      By 1962, when the federal government renounced its policy of subsidizing segregation, and by 1968, when the Fair Housing Act banned private discrimination, the residential patterns of major metropolitan areas had already been set in concrete. White suburbs that had previously been affordable to the Black working class were no longer so, both because of the increase in suburban housing prices and because other federal policies had depressed Black incomes while supporting those of Whites.

      …Further, when researchers have looked closely at the handful of experimental programs that have assisted low-income families with young children to move to integrated housing, they have observed positive effects on those children’s performance in school.

      …That’s why it's so critical, for example, to challenge those who would misinform young people about the country's recent past. Even today, the most widely used middle and high school history textbooks neglect to mention the role of public housing in creating segregation, and they portray the FHA as an agency that made home ownership possible for working-class Americans, with no mention of those who were excluded. Likewise, they describe state-sponsored segregation as a strictly Southern phenomenon, and they portray discrimination in the North as the result of private prejudice alone, saying nothing about the active participation of local, state, and federal governments….

Confronting our Beliefs about Poverty and Discipline

[These excerpts are from an article by Edward Fergus in the February 2019 issue of Phi Delta Kappan.]

      Dating back to Brown v. Board of Education, Mendez v. Westminster, and other landmark court decisions of the mid-20th century, civil rights advocates have prioritized efforts to desegregate school systems and ensure the equitable distribution of educational resources.

      However, the civil rights struggle has always focused not just on passing laws and securing resources but also on challenging the beliefs that underlie segregation and worsen its effects. And the more researchers have learned about the psychology of racial discrimination, the more obvious the need to tackle certain biases that continue to be prevalent among educators, resulting in deficit-based thinking…, low academic expectations for particular students…, and misguided claims of “colorblindness”….

      An additional form of bias — poverty-disciplining belief — has received somewhat less attention from equity adVocates, but it appears to be quite common in schools. Poverty-disciplining belief is the assumption that poverty itself is a kind of “culture,” characterized by dysfunctional behaviors that prevent success in school….In effect, it pathologizes children who live (or whose parents lived) in low-income communities. And while it doesn't focus on race per se, it is often used as a proxy for race and to justify racial disparities in disciplinary referrals, achievement, and enrollment in gifted, AP, and honors courses, as well as to justify harsh punishments for “disobedience” or “disorderly conduct” or “disrespect….”

      The belief that poor people are in need of discipline rests, in turn, on a highly debatable premise, the idea that the economic status of a community determines the value of its cultural practices: The poorer the community, the more impoverished and dysfunctional its culture; the richer the community, the more culturally refined it must be.

      That’s hardly a new idea; elites in every society tend to assert the superiority of their chosen customs, norms, and behaviors. But in recent decades it has been given an academic sheen, beginning with the cultural deprivation theory (also known as the “culture of poverty” argument) of the 1960s, which maintained that the low academic perfor-mance of racial and ethnic minorities stemmed from their deficient cultural practices….Supposedly, parents in certain cultures tend to suppress the development of linguistic, cognitive, and affective skills their children need to succeed in school.

      …Among the nearly 1,600 practitioners surveyed, nearly a third agreed (ranging from somewhat to strongly agree) that the values students learn growing up in disadvantaged neighborhoods conflict with school values; more than a quarter agreed that such students do not value education, and roughly one in six believe poor kids lack the abilities necessary to succeed in school. In short, a significant percentage of school practitioners appear to believe that the values and behaviors learned in low-income communities conflict with those taught in school.

      Increasingly, I’ve found also that educators are framing their assumptions about poor and minority children in terms borrowed from the biological and cognitive sciences, especially research into the effects of long-term exposure to lead paint, food insecurity, violence, and other environmental dangers, and a lack of exposure to certain positive influences, such as frequent reading time at home….

      In short, not only do significant numbers of school practitioners believe that when students from low-income backgrounds struggle it must be the fault of their culture, but some practitioners are tempted to dress up that belief in “scientific” evidence about what it means to grow up in poverty. Supposedly, it is the nature of low-income families to expose their children to trauma and to deny them appropriate support for language development.

      But in fact, mountains of research findings suggest that while poverty may put children at somewhat elevated risk for trauma and other negative influences on development, poverty is far from a deterministic condition….If an individual student has trouble learning to read, behaving appropriately in class, or meeting other expectations, it is for complex reasons having to do with that individual and the specific people and institutions in their lives. It is not simply because they are poor….

      The challenge for educators is to get over the habit of pathologizing entire populations of young people, as though the struggles of individual students could ever be explained merely by pointing out that they're poor. We need to get it into our heads that poverty is not a determin-istic condition; it doesn't tell us anything about the ways in which any particular kid — from any particular race or ethnicity — will develop, the kinds of instruction they’ll need, or the level of “discipline” they require.

      Further, given the inevitability of our own blind spots, we have a responsibility to seek out regular feedback on the racial and economic ecology of our schools. As Eduardo Bonilla-Silva…has argued, even if there are no out-and-out racists among us, racism is still often woven tightly into the social fabric of our schools, subtly influencing our assumptions about ability, intelligence, behavior, and more….

Why We Need a Diverse Teacher Workforce

[These excerpts are from an article by Dan Goldhaber, Roddy Theobald and Christopher Tien in the February 2019 issue of Phi Delta Kappan.]

      …A significant body of literature argues that a match between the race and ethnicity of teachers and students leads to better student outcomes, particularly in high-poverty environments with significant at-risk student populations….At least three commonly cited theoretical rationales suggest why racially matched teacher role models have positive educational benefits for students of color in particular. The first is that students of color, particularly those living and attending schools in disadvantaged settings, benefit from seeing role models of their race in a position of authority….In particular, some scholars have suggested that having an adult role model who exemplifies academic success could alleviate the stigma of “acting White” among some students of color….

      Second, some researchers argue that teachers of color are more likely to have high expectations for students of color….This is important because students of color, especially Black students, appear to be more sensitive to teacher expectations than middle-class White students….And when teachers allow negative stereotypes to lower expectations, a “self-fulfilling prophecy” takes hold to perpetuate poor performance of students of color….

      Finally, some argue that teachers of different backgrounds are able to draw on their own cultural contexts when determining instructional strategies and interpreting students’ behavior. A vast literature finds that Black students are more likely to be disciplined and suspended from school than other students, even after accounting for the nature of students’ misconduct….These dispari-ties in disciplinary actions could be based in part on teacher interpretation of student behavior, which may be informed by negative stereotypes….

      These theoretical arguments suggest several ways that increasing the diversity of the teacher workforce might improve outcomes for students of color. When empirical researchers have considered the effects of teacher diversity, they have generally found that, all else being equal (and, importantly, all else is often not equal), students of color do appear to benefit when they are taught by a teacher of the same race or ethnicity. Much of this empirical evidence focuses on student test performance, but we also discuss empirical evidence related to other important outcomes such as subjective evaluations and discipline….

      The theoretical arguments and empirical evidence generally support the notion that improving the diversity of the teacher workforce would help close racial achievement gaps in public schools. However, teacher workforce diversity is just one of many ways to improve the education system, and diversifying the teacher workforce may present substantial challenges and potential unintended consequences. One challenge is that we know very little about what contributes to the lack of diversity in the teaching workforce. We must understand the answer to that question before we can design effective strategies to recruit more teachers of color. Another challenge is that, while the empirical evidence is consistent with the three theoretical arguments about the importance of teacher workforce diversity discussed above, we don’t have conclusive evidence for why students of color appear to benefit from assignment to a teacher of the same race….

Voluntary Integration in Uncertain Times

[These excerpts are from an article by Jeremy Anderson and Erica Frankenberg in the February 2019 issue of Phi Delta Kappan.]

      The U.S. Supreme Court’s 1954 decision in Brown v. Board of Education — declaring state laws segregating students by race to be “inherently unequal” — stands as one of the most important decisions in the nation’s history. Over the following 15 years, and with help from other branches of the federal government, courageous Black lawyers and plaintiffs, and Black educators working behind the scenes…, the South’s schools were transformed. Despite initial protests and fierce resistance in many local communities, the region’s public school systems became the most integrated in the country and remained so for several decades.

      Since the 1990s, however, many judges have chosen to release school districts from court-ordered desegregation plans, which has prompted a wave of resegregation, especially in the South….Further, the decline in court supervision means that any new integration efforts must be carried out voluntarily by school districts. However, even voluntary school integration has been dealt a setback, thanks to the U.S. Supreme Court’s 2007 decision in Parents Involved in Community Schools v. Seattle School District #1, which limited the ways in which districts can choose to promote diversity and reduce racial isolation….

      This seeming reversal of Brown comes despite growing evidence that students from all backgrounds, White students included, tend to benefit both academically and socially from racial integration….Additionally, students who have attended desegregated schools tend to be more comfortable with those of other racial and ethnic backgrounds, and better prepared to participate in our increasingly diverse democracy…than those who were educated in more racially isolated schools….

      Convinced of these benefits, many school district officials continue to pursue school integration even though they are not legally required to do so, and even though it can be very challenging politically for them to change existing student assignment policies….However, since the Parents Involved decision, those officials have received mixed and confusing signals about which methods of voluntary integration they are and are not permitted to use.

      In 2009, recognizing that many district leaders were confused about their options, Congress authorized a small grant program to provide some districts with assistance. Further, in 2011, the Obama administration published additional legal and policy guidance including examples of ways in which schools could legally pursue voluntary integration and methods that incorporate race as a factor in school assignment decisions alongside those that use methods not involving race….And in 2016, the U.S. Department of Education proposed a larger program to assist districts in designing or implementing voluntary integration strategies. However, that program was cancelled by newly appointed Secretary of Education Betsy DeVos in March 2017….

      This back-and-forth over what is and isn’t permissible has had a chilling effect on school districts’ voluntary integration plans. While some districts have forged ahead, others have given up on their plans, fearing that whatever approach they choose would run into legal challenges….

School Segregation: A Realist’s View

[These excerpts are from an article by Jerry Rosiek in the February 2019 issue of Phi Delta Kappan.]

      As a nation, we often think of racial segregation in schools as an unjust form of social organization that we put behind us long ago, like aristocratic monarchies or the denial of women's right to vote. The inequity of these arrangements is so obvious, it feels indisputable that we should never return to them. The truth, however, is that racial segregation has incrementally returned to U.S. schools over the last 30 years. Like a disease that was never fully cured, school segregation has come out of remission and returned in a form that is more pervasive and harder to treat.

      This relapse should not be surprising. The U.S. Justice Department actively desegregated public schools for only five years. Although the Supreme Court made its landmark Brown v. Board of Education decision in 1954, it was not until 1968 that the Green v. County School Board decision enabled federal enforcement of desegregation orders. That same year Richard Nixon was elected president and soon ordered the Justice Department to reduce enforcement of desegregation rulings….As the cases already in the system ran their course, the momentum of the judicial desegregation movement dissipated. By 1980, desegregation of the schools had peaked.

      This reduction in enforcement was followed by an organized effort by conservative activists to roll back desegregation gains in the courts. In 1992, the Supreme Court Freeman v. Pitts decision made it easier to get desegregation orders lifted, and since that time, more than half of the desegregation orders issued by federal courts have indeed been rescinded. In almost every case where such orders have been lifted, school districts have moved back in the direction of greater segregation….As a result, 50 years after the Green decision, our schools are more racially segregated by some measures now than they were in 1968….

      The theory of change underlying court-mandated desegregation was that a generation of citizens educated in racially desegregated schools would normalize racial integration. The hope was that communities would achieve what the courts called “unitary status,” a condition in which racism would dissipate enough that communities could be trusted not to racially segregate their schools once court orders were no longer in place. Given the rapidity and consistency with which school districts have resegregated, we are forced to conclude that this was a false hope.

      …The 1974 U.S. Supreme Court ruling Milliken v. Bradley struck down efforts to desegregate schools across district lines. In demographically diverse districts, segregation often involves creating schools with few or no White students, so as to maintain relatively high percentages of White students at the remaining schools….In other cases, we see secessionist movements where wealthy predomi-nantly White neighborhoods break away from more diverse school systems and form their own school districts….

      The new segregation also combines race and class segregation. Because of persistent patterns of race and class segregation in housing, as well as racial disparities in wealth accumulation, students of color and low-income students of all races are concentrated in the same schools. Wealthier households (in which White families are overrepresented) can afford to relocate to residential zones with more political clout, and once there, these families invest their political capital in securing advanced curriculum and other educational resources for their schools, but not for others. Voucher systems, open enrollment, and charter schools have all been offered as means of disrupting the influence of residential segregation on school enrollment; however, the evidence indicates such school choice plans either increase school segregation or leave it unaltered….

      Efforts to rezone schools to address racial segregation increasingly are met with objections that such efforts vio-late the principle of color-blind jurisprudence, objections delivered without the slightest sense of irony….

      Racial segregation in schools today is unequivocally a national phenomenon. From 1970 to the early 1980s, federal desegregation orders focused mainly on the Southeastern states, resulting in the lowest levels of racial segregation in the country. However, while segregation is now on the rise again in the South, it is no longer concentrated in that region, having increased dramatically in major urban centers in the North, Midwest, and West New York City, for example, currently has the most racially seg-regated schools in the United States….

      Further, even where federal desegregation orders have remained in force, racial segregation has quietly reappeared at the classroom level…..

      The tendency of White citizens to hoard educational resources for themselves has proven more resilient than civil rights era desegregationists anticipated. Denied the instruments of explicit law and policy, the desire for White majority educational spaces has found other means of enactment. It has used residential housing patterns and school zoning policy. It has bent the courts to its defense. It has camouflaged itself with new rhetoric and new ratio-nales. It has moved into the capillaries of our education system, segregating students at the classroom level through tracked curriculum. What it has not done is go away….

      Although the form of racial segregation has evolved, its odious effects have remained consistent. Black children in racially isolated schools perform less well on standardized tests, their graduation rates are lower, and college attendance is lower. Income levels and wealth accumulation across generations are lower for Black people who attend racially segregated schools, and lower health outcomes across a person's life span are correlated with racially iso-lated schooling….Careful research suggests that these effects are not the consequence of characteristics found within students or their families. Instead, they are strongly correlated with the greater per-pupil spending that come with enrollment in racially integrated or pre-dominantly White schools….In other words, they are a consequence of the way resources follow White students….

      Anti-racist professional development and activism are already practiced in many places, to be sure. Unfortunately, these practices remain largely on the margins of our education system. The fact that we are sending our children to racially resegregating schools means that anti-racist policy and practice must become mainstream. Anything less con-stitutes a failure to face the persistent reality of racism in our schools.

United States Alone in Opposing US Resolution

[This news clip by Marian Starkey is in the March 2019 issue of Population Connection.]

      At the 55th plenary meeting of the UN General Assembly in December, the United States was alone in voting against a nonbinding resolution on the “Intensification of efforts to prevent and eliminate all forms of violence against women and girls: sexual harassment.” The rest of the attending countries either voted yes (130) or abstained from voting (31). Countries that voted yes included Afghanistan, Congo, Myanmar, North Korea, Saudi Arabia, South Sudan, and Yemen.

      In another vote that same day, on “Child, early, and forced marriage,” the United States was one of two countries to vote no. The other country was Nauru, a small Pacific island nation that serves as a detention camp for refugees and migrants to Australia. In that vote, 134 countries voted yes and 32 abstained from voting.

      References to sexual and reproductive health in both resolutions raised concerns among American delegates that voting yes could be interpreted as supporting or promoting abortion.

Climate Change Impacts on Fisheries

[These excerpts are from an article by Eva Plaganyi in the 1 March 2019 issue of Science.]

      Food security, climate change, and their complex and uncertain interactions are a major challenge for societies and ecologies. Global assessments of predicted changes in crop yield under climate change, combined with international trade dynamics, suggest that disparities between nations in production and food availability will escalate. But climate change has already affected productivity. For example, weather-related factors caused declines in global maize and wheat production of 3.8% and 5.5%, respectively, between 1980 and 2008….that indicates a 4.1% decline between 1930 and 2010 in the global productivity of marine fisheries, with some of the largest fish-producing ecoregions experiencing losses of up to 35%. Their spatial mapping can help to inform future planning and adaptation strategies….

      Losses in seafood production are of concern because seafood has unique nutritional value and provides almost 20% of the average per-person intake of animal protein for 3.2 billion people. However, wild capture fisheries yield has likely already reached its natural limits. Coupled with projected human population increases, this means that per-person seafood availability is certain to decline. This shortfall will be exacerbated by future losses in fisheries production as a result of warming….Aquaculture, which parallels the intensification of crop production on land, has been proposed as one potential solution. However, this sector’s initial high growth rates have declined, and its future scope for growth is uncertain and susceptible to environmental extremes. Given the widening gap between current and projected per-person fisheries yield…, other protein sources and solutions will be needed to avoid food shortages.

      Future fisheries production may be at even greater risk considering that, owing to anthropogenic climate change, the oceans are continuing to warm even faster than originally predicted. Moreover, extreme temperature events are on the increase, with profound negative consequences for fisheries and aquaculture. Regional declines in some species will thus increasingly not be counterbalanced by increases, as populations exceed their thermal optima or become subject to other environmental stressors such as reduced oxygen concentration and ocean acidification. These additional effects could not be accounted for….

      Regional fishery managers and stake-holders can influence future sustainable fisheries production and food security through the development, adoption, and enforcement of sustainable management strategies and practices. These strategies should be pretested for robustness to temperature-driven changes in productivity. However, global efforts are needed to contain the rise in global mean temperature to no more than 2°C, beyond which the integrity of marine and terrestrial ecological sys-tems, and hence our food supplies, become compromised.

Mobilize for Peace

[This editorial by Jonathan A. King and Aron Bernstein in the 1 March 2019 issue of Science.]

      Fifty years ago, on 4 March 1969, research and teaching at the Massachusetts Institute of Technology (MIT) came to a halt as students, faculty, and staff held a “research strike” for peace. The strike protested United States involvement in the Vietnam War and MITs complicity in this engagement through its Instrumentation Laboratory (now the Draper Laboratory), a major contracting lab for the U.S. Department of Defense. The anniversary of this activism by scientists…is a reminder that the scientific community must continue to recognize its social responsibilities and promote science as a benefit for all people and for a peaceful world.

      By the end of 1968, nearly 37,000 American soldiers had died in the Vietnam conflict and a draft lottery pulled about 300,000 men into the military in that year alone. In the years following the MIT strike, opposition to the U.S. role in Vietnam grew across the nation, particularly on college campuses. Academia condemned the nation's hand in the war, including the American Association for the Advancement of Science…, which, in 1972, passed a resolution denouncing U.S. involvement in Vietnam, stating that scientists and engineers did not endorse such “wanton destruction of man and environment.” These activities arguably helped to end the Vietnam Wax. In addition, the March 4th strike elevated the voices of scientists urging the use of research and technology for peaceful purposes. Indeed, some years later, as nuclear weapons proliferated and tensions escalated between the United States and the Soviet Union, scientists protested again. They helped initiate the national Nuclear Weapons Freeze campaign, which brought more than 1,000,000 people to New York’s Central Park in protest in 1982. The event galvanized public support to curb the nuclear arms race, and limitations were eventually negotiated between the two nations.

      Over the past 50 years, science has seen rapid growth in biotechnology, computer science, and telecommunications, among other fields. These advances have opened up rich arenas for applications of research and technology, and consequently, have raised ethical concerns. For example, advances in epidemiology and biochemistry identified environmental and occupational toxins and carcinogens, but engendered strong resistance from manufacturers. And in documenting accelerating climate change and its potentially devastating social and economic consequences, the scientific community has informed national and global climate policies, but has been met by resistance from sectors of the energy industry.

      Such commitment and engagement must now be extended once again to the renewed danger of nuclear war. Last month, President Trump announced that the United States would pull out of the Intermediate-Range Nuclear Forces Treaty, threatening a new nuclear arms race with Russia In return, last week, President Putin issued a warning about bolstering Russia’s nuclear arms. The 1987 pact bans the development of certain ground-based missiles and has been a model treaty for arms control agreements between major powers. Withdrawing from this treaty is a threat to U.S. national security and to Europe. Congress has also supported spending $1.7 trillion over the next 25 years to upgrade land-launched nuclear missiles, nuclear missile-armed submarines, and aircraft armed with nuclear missiles and bombs.

      The scientific community needs to remind the Trump administration, Congress, and the public of the destructive power of atomic bombs and to communicate how federal investment in housing, health care, education, environmental protection, sustainable energy development, and basic and biomedical research will be sacrificed to build up a nuclear weapons arsenal. Young scientists, in particular, need to fight for a peaceful future and speak out against profound misuses of resources for war. It is time to mobilize for peace in ways that effectively promote social responsibility in science.

Is Antarctica Collapsing?

[These excerpts are from an article by Richard B. Alley in the February 2019 issue of Scientific American.]

      Glaciers are melting, seas are rising. We already know ocean water will move inland along the Eastern Seaboard, the Gulf of Mexico and coastlines around the world. What scientists are urgently trying to figure out is whether the inundation will be much worse than anticipated—many feet instead of a few. The big question is: Are we entering an era of even faster ice melt? If so, how much and how fast? The answer depends greatly on how the gigantic Thwaites Glacier in West Antarctica responds to human decisions. It will determine whether the stingrays cruising seaside streets are sports cars or stealthy creatures with long, ominous tails.

      Global warming is melting glaciers up in mountainous areas and expanding ocean water, while shrinking ice at both poles. Averaged over the planet's oceans for the past 25 years, sea level has risen just over a tenth of an inch per year, or about a foot per century. Melting the rest of the globe's mountain glaciers would raise the sea a little more than another foot. But the enormous ice sheets on land in the Arctic and Antarctic hold more than 200 feet of sea-level rise; a small change to them can create big changes to our coasts. Ice cliffs many miles long and thousands of feet high could steadily break off and disappear, raising seas significantly.

      Well-reasoned projections for additional sea-level rise this century have remained modest—maybe two feet for moderate warming and less than four feet even with strong warming. Scientists have solid evidence that long-term, sustained heating will add a lot to that over ensuing centuries. But the world might be entering an era of even more rapid ice melt if the front edges of the ice sheets retreat.

      To learn whether this could happen, we look for clues from changes underway today, aided by insights gained about Earth's past and from the physics of ice. Many of the clues have come from dramatic changes that started about two decades ago on Jakobshavn Glacier, an important piece of the Greenland Ice Sheet. Glaciers spread under their own weight toward the sea, where the front edges melt or fall off, to be replaced by ice flowing from behind. When the loss is faster than the flow from behind, the leading edge retreats backward, shrinking the ice sheet on land and raising sea level.

      During the 1980s Jakobshavn was among the fastest-moving glaciers known, racing toward Baffin Bay, even though it was being held back by an ice shelf—an extension of the ice floating on top of the sea. In the 1990s ocean warming of about 1.8 degrees Fahrenheit (one de-gree Celsius) dismantled the ice shelf, and the glacier on land behind it responded by more than doubling its speed toward the shore. Today Jakobshavn is retreating and thinning extensively and is one of the largest single contributors to global sea-level rise. Geologic records in rocks there show that comparable events have occurred in the past. Our current observations reveal similar actions transforming other Greenland glaciers.

      If Thwaites, far larger, unzips the way Jakobshavn did, it and adjacent ice could crumble, perhaps in as little as a few decades, raising sea level 11 feet. So are we risking catastrophic sea-level rise in the near future? Or is the risk overhyped? How will we know how Thwaites will behave? Data are coming in right now….

      Warming air can create lakes on top of the ice shelves. When the lakes break through crevasses, a shelf can fall apart. For example, the Larsen B Ice Shelf in the Antarctic Peninsula, north of Thwaites, disintegrated almost completely in a mere five weeks in 2002, with icebergs breaking off and toppling like dominoes. That did not immediately raise sea level—the shelf was floating already—but the loss of the shelf allowed the ice sheet on land behind it to flow faster into the ocean—like pulling a spatula away, allowing the batter to run. The ice flowed as much as six to eight times quicker than it had been moving earlier. Fortunately, there was not a lot of ice behind the Larsen B Ice Shelf in the narrow Antarctic Peninsula, so it has raised sea level only a little. But the event put society on notice that ice shelves can disintegrate quickly, releasing the glaciers they had been holding back. Ice shelves can also be melted from below by warming seawater, as happened to Jakobshavn.

      When shelves are lost, icebergs calve directly from ice-sheet cliffs that face the sea. Although this delights passengers on cruise ships in Alaska and elsewhere, it speeds up the ice sheets demise. At Jakobshavn today, the icebergs calve from a cliff that towers more than 300 feet above the ocean's edge—a 30-story building—and extends about nine times that much below the water. As these icebergs roll over, they make splashes 50 stories high and earthquakes that can be monitored from the U.S.

      So far ice-shelf loss and ice-cliff calving are contributing moderately to sea-level rise. But at Thwaites, this process could make the rise much more dramatic because a geologic accident has placed the glacier near a “tipping point” into the great Bentley Subglacial Trench….

Ghosts of Wildlife Past

[These excerpts are from an article by Rachel Nuwer in the February 2019 issue of Scientific American.]

      Kenya’s national parks serve as oases in an increasingly human-crowded world, but they are not a conservation panacea. As in much of East Africa, a striking two thirds of the country's wildlife resides outside of national parks—and these animals are not welcome visitors for many landowners, who see them as competition for livestock. But in a rare win-win situation for humans and nature, researchers have now shown that livestock and wildlife can benefit from each other’s presence. A study published last October in Nature Sustainability found that wildlife can boost bottom lines by providing opportunities for tourism, and livestock improve the quality of grass for all grazing species.

      Recent history explains this symbiosis. Animals and savanna grasses evolved together for millennia—but Kenya’s wildlife population dropped by about 70 percent between 1977 and 2016, according to a 2016 PLOS ONE study. With fewer animals around to encourage new growth by removing old and dead grass stems, it seems livestock have stepped in to fill that ecological role.

      …To the team members’ surprise, they found I only benefits in combining moderate numbers of cattle and wildlife. At mixed properties, livestock treated for ticks reduced the overall number of those pathogen-carrying parasites by 75 percent—and grass quality was higher than in livestock- or wildlife-only areas, which tended to be overgrazed or underg razed, respectively….

Reengineering the Colorado River

[These excerpts are from an article by Heather Hansman in the February 2019 issue of Scientific American.]

      …wanted to see if holding the river at a consistent level would aid the struggling native bug population, 85 percent of which lay their eggs in the intertidal zone. Those eggs can get wet, but they cannot get dry; eggs laid at high tides desiccate within an hour of the water dropping.

      Bugs might seem like a lowly thing to focus on. But they form the basis of a complex food web. When their numbers drop, that reduction affects species, such as bats and endangered humpback chub, that feed on them. In a national park held up as an iconic wild, Kennedy and his group are trying to figure out why, accord-ing to their research published in 2016 in BioScience, the Grand Canyon section of the Colorado has one of the lowest insect diver-sities in the country….

      Last summer the researchers were testing whether adjusting dam releases so that the Colorado runs closer to its natural course might help insect populations recover. In those tests, they artificially created the kind of flow patterns that allowed life to flourish before the dam went in—without removing the dam itself.

      Nearly 40 million people depend on the Colorado for the necessities of daily life, including electricity, tap water and the irrigation of 10 percent of land used for U.S. food production. Ever since Glen Canyon Darn opened in 1963, the river has been engineered to accommodate these demands. Doing so changed the ecosystem balance, which was dependent on ingredients such as sediment, snowmelt and seasonal flows. For more than 30 years researchers have been trying to figure out how to help the ecosystem coexist with human needs, and they are finally beginning to test some solutions. By working out an experimental flow schedule that minimally impacted power generation, the 2018 bug tests marked one of the first times that dam operations were adjusted for species health in the Grand Canyon.

      Meanwhile, though, the river is dwindling. The Colorado River Basin has been in a drought for almost two decades; 2018 was the third-driest year ever recorded. Since 2000 ambient temperatures in the basin have been 1.6 degrees Fahrenheit warmer than 20th-century averages, and researchers predict they will reach up to 9.5 degrees F hotter still by 2100. The effects of climate change could decrease river flow by as much as half by the end of the century. With earlier snowmelt and more evaporation, the Bureau of Reclamation has predicted that it may have to cut the amount of water it sends downstream for the first time—as soon as 2020. That will stress every part of the system, from hydropower and city water supplies to native fish populations. It will also mean less room for experimental flows, a tool the scientists think is critical for understanding how to protect the canyon.

      The insect research is a meaningful step toward sustaining the river for habitat as well as for humans. It also runs straight into a core conflict between science and Colorado River policy: scientists want the flexibility to experiment, whereas power and water managers want stability. As the Colorado dries up, this conflict will intensify. And yet if Kennedy and others can show that changing the flow can bring back insect populations, it could make ecosystem health a bigger priority for those who manage the most used river in the West….

      Giving scientists a voice in water management has led to new insights about how the Colorado River reservoirs are suffering from climate change. Much of the news is alarming. A 2017 study…found that average Colorado River flows in the 21st century were 19 percent lower than in the 20th. They predicted flows could drop by up to 55 percent by 2100 as a result Lathe effects of global warming….

      There is also problematic math at Lake Powell. Because the Colorado's water is allocated down to virtually the last drop, the lake level is crucial to a 1922 legal compact that guarantees 8.23 million acre-feet of water will flow past Lees Ferry every year. The Bureau of Reclamation built reservoirs—including Powell—starting in the 1950s. But these storage systems only work if they are replenished. Lake Powell is considered “full” at 3,700 feet above sea level; the last time that happened was 1986. In 2002, the driest year on record, only as million acre-feet flowed into Powell from upstream on the Colorado. Because Lake Powell’s entire purpose is to keep the downstream water supply consistent even when it does not rain or snow, the legally obligated 8.23 million acre-feet still went out.

      This logic, however, is fundamentally flawed. The compact water was allocated based on calculations done by the Bureau of Reclamation in the early 1900s, the wettest recorded period in measured history, which concluded that 18 million acre-feet of water flowed through the river basin every year. Data collected from USGS river gauges installed at Lees Ferry in 1922 have showed that average yearly flows are actually 14.8 million. Because the compact is federal law, the 8.23 million acre-feet of downstream obligations still stand. Water managers call this a structural deficit, and it means that if every state claims its entire share—a near-future scenario thanks to projects like the Lake Powell Pipeline—there will not be enough to go around.

      The accelerating drought has become so threatening that in 2018, seven “basin states” drafted contingency plans. Each state outlined how much of its allocated compact water it would leave in reservoirs if Lake Powell’s level hit 3,525 feet above sea level—just high enough to comfortably maintain power production at the dam. (In November 2018 Powell was at 3,588 feet.) Although interim guidelines came out in 2007, this official step marked the first time since the compact was signed nearly 100 years ago that the basin states made a legally enforceable plan for a drier future. Finally, policy is starting to reflect science….

Urine Trouble

[These excerpts are from an article by Andy Extance in the February 2019 issue of Scientific American.]

      In a disturbing trend, scam artists are using commercially sold fake urine to fool doctors into prescribing pain medications such as hydrocodone—which can then be consumed or illegally sold. The synthetic pee lets patients pass tests intended to ensure they are not already taking opioid medications or drugs of abuse….

      Hoping to address the situation, Kyle and his pathologist colleague Jaswinder Kaur have now shown how legal indulgences— F including chocolate, coffee and cigarettes—can help distinguish real pee from fake….

      The new method, described at the annual Society of Forensic Toxicologists (SOFT) meeting last October in Minneapolis, looks for four substances common in urine: caffeine and theobromine, both found in chocolate, tea and coffee; cotinine, produced as nicotine breaks down; and urobilin—degraded hemoglobin that gives urine its yellow color. The technique employs liquid chromatography to separate urine, just as water spilled on paper separates ink into different colors. The compounds then flow into mass spectrometers that identify them by their molecular weights.

      …the test will not detect people passing off others’ pee as their own. “If someone is carrying synthetic urine or somebody else’s clean urine, you have to do observed collection,” she says. Peace also warns that fake urine makers could easily add substances such as caffeine or theobromine to their products.

      Some already do, Kyle says. He emphasizes that testing must therefore look for compounds naturally produced in our bodies (urobilin, in this case). Combining that with commonly consumed substances makes the test even more powerful—and is potentially more practical than watching people pee.

Call the Midwife … If You Can

[These excerpts are from an editorial by the editors in the February 2019 issue of Scientific American.]

      Despite the astronomical sums that the U.S. spends on maternity care, mortality rates for women and infants are significantly higher in America than in other wealthy countries. And because of a shortage of hospitals and ob-gyns, especially in rural areas, many women struggle to access proper care during pregnancy. Moreover, the rate of cesarean sections is exceedingly high at 32 percent—the World Health Organization considers the ideal rate to be around 10 percent—and 13 percent of women report feeling pressured by their providers to have the procedure.

      Widespread adoption of midwife-directed care could alleviate all these problems. In many other developed countries, such as the U.K., France and Australia, midwifery is at least as common as care by obstetricians. In the U.S., certified midwives and nurse-midwives must hold a graduate degree from an institution accredited by the American College of Nurse-Midwives, and certified professional midwives must undergo at least two years of intensive training. This is designed to make midwives experts in normal physiological pregnancy and birth. Thus, for women with low-risk pregnancies who wish to deliver vaginally, it often makes sense to employ a midwife rather than a more costly surgeon. Yet only about 8 percent of US. births are attended by midwives.

      The roots of America's aversion to midwifery go back to the late 1800s, when the advent of germ theory and anesthesia reduced much of the danger and discomfort associated with childbirth. The benefits of these technologies brought doctors to the forefront of maternity care and pushed midwives aside. Obstetricians helped to bar midwives from practicing in hospitals, which were now considered the safest birth settings. By the ear-ly 1960s midwifery was virtually obsolete.

      It has made a comeback since then, with practitioners just as well trained as doctors to supervise uncomplicated deliveries. Studies show that midwife-attended births are as safe as physician-attended ones, and they are associated with lower rates of C-sections and other interventions that can be costly, risky and disruptive to the labor process. But midwifery still remains on the margins of maternity care in the U.S.

      …Half of planned nonhospital births are currently paid for by patients themselves, compared with just 3.4 percent of hospital births. Thus, a less expensive birth at home may paradoxically be out of reach for women who cannot afford to pay out of pocket. U.S. hospitals charge more than $13,000, on average, for an uncomplicated vaginal birth, whereas a similar midwife-attended birth outside of the hospital reduces that figure by at least half. Insurers would save money by embracing midwife-attended, nonhospital birth as a safe and inexpensive alternative.

      A national shortage of birth centers further limits women’s choices. These homelike settings are designed to support naturally laboring women with amenities such as warm baths and spacious beds and are consistently rated highly in surveys of patient satisfaction. Yet there are only around 350 existing freestanding birth centers in the entire nation, and nine states lack regulations for licensing such facilities. More government support for birth centers would help midwives meet a growing demand, which has already fueled an increase of 82 percent in centers since 2010.

      Policy makers, providers and insurers all have good reasons to encourage a shift toward midwifery. The result will be more choices and better outcomes for mothers and babies.

The Law and Vaccine Resistance

[These excerpts are from an editorial by Dorit Rubenstein Reiss in the 15 February 2019 issue of Science.]

      Last week, the Centers for Disease Control and Prevention announced that more than 100 cases of measles, spanning 10 states, had been reported in the United States since the beginning of the year. This news came on the heels of the World Health Organization’s estimate of over 200,000 cases of measles in 2018. These numbers signal the reemergence of a preventable, deadly disease, attributed in significant part to vaccine hesitancy. Communities and nations must seriously consider leveraging the law to protect against the spread of this highly contagious disease.

      In the United States, measles was deemed “eliminated” in 2000 because of vaccination success. Since then, its reemergence has been associated with a resistance to vaccination. This also reflects the fact that unvaccinated U.S. residents visit countries that have seen large measles outbreaks (such as Ukraine, the Philippines, and Israel), become infected, and bring the disease back home.

      Outbreaks in the United States are still fewer than in, say, Europe because of unique U.S. policies and laws that maintain high vaccination coverage. All 50 states and the District of Columbia have laws requiring vaccinations for school and daycare attendance. School mandates have proven very effective: The stronger they are, the higher the vaccination rate, and the lower the risk of outbreaks.

      …States have extensive leeway to protect public health, and courts have consistently upheld strong school immunization mandates. Thus, states could tighten nonmedical exemptions (for example, by requiring consultation with a doctor) or remove these exemptions completely from school mandates. Valid medical exemptions are important, but it is less clear whether nonmedical exemptions are appropriate. Some scholars are concerned that eliminating nonmedical exemptions may generate resentment among parents and interfere with parental autonomy. Others—including professional medical associations—disagree, because mandates protect children, and a parent’s freedom to send an unvaccinated child to school places classmates at risk of dangerous diseases. There is a strong argument for removing nonmedical exemptions, and at the least, they should be hard to get, to further incentivize parents to vaccinate. In many states, however, getting an exemption is as easy as checking a box. States and localities could also require schools to provide their immunization rates to parents at the start of the school year.

      Beyond school mandates, states can consider other legal tools that have not yet been used. States could implement workplace mandates for those working with vulnerable populations, such as health care workers, teachers in schools, and providers of daycare. States could impose tort liability (civil law damages for harm) when unexcused refusal to vaccinate leads to individuals becoming infected unnecessarily or worse, to a large outbreak. States could permit teenagers to consent to vaccinations without parental approval. And states could mandate vaccinations to enroll in institutions of higher education.

      Vaccine hesitancy is a problem with many components. In handling it, societies should improve public understanding of vaccinations but also not hesitate to use the law to prevent deadly diseases from spreading.

How Rabbits Escaped a Deadly Virus—At Least for Now

[These excerpts are from an article by Elizabeth Pennisi in the 15 February 2019 issue of Science.]

      In Australia, a few dozen European rabbits introduced in the mid-1800s for hunters did what the animals famously do. They multiplied until hundreds of millions were chowing down on crops. So, in 1950, after a smallpoxlike virus found in South American rabbits turned out to kill the European relative, Australian authorities released the virus into the wild, cutting the rabbit population by 99%. A few years later, the virus, called myxoma, was released in France and eventually spread to the United Kingdom.

      …Within a decade, rabbit numbers were on the rise again as some evolved resistance to this deadly infection and the virus itself became less deadly.

      One allele shift affected the rabbits’ interferon, a protein released by immune cells that sounds the alarm about a viral attack and helps trigger an immune response. Compared with preinfection rabbits, modern rabbits make an interferon that is better at responding to the biocontrol virus, the researchers found when they added different versions of the protein to rabbit cell lines.

      The virus has not stood still. In 2017, Holmes and his colleagues reported that in the 1970s the virus developed a greater ability to suppress the rabbit's immune responses. That change, as well as the natural emergence of another rabbit-killing virus, has caused populations to decline again. But in contrast to the parallel evolution in rabbits, myxoma viruses in the various locations took different genetic paths to regaining potency….

Controversial Flu Studies Can Resume, Panel Says

[These excerpts are from an article by Jocelyn Kaiser in the 15 February 2019 issue of Science.]

      Controversial lab studies that modify bird flu viruses in ways that could make them more risky to humans will soon resume after being on hold for more than 4 years….last year, a U.S. government review panel, quietly approved two projects previously considered so dangerous that federal officials had imposed an unusual moratorium on the research….

      The outcome marks the latest twist in a nearly decadelong debate over the risks and benefits of studies that aim to make pathogens more potent or more likely to spread in order to better understand them and prepare defenses. And it represents the first test of a new federal review process intended to ensure that government funding flows to such studies only when they are scientifically and ethically justifiable and done under strict safety rules….

      Some other researchers are sharply critical of the approvals, saying the review lacked transparency. After a long public discussion to develop new standards that “consumed countless weeks and months of time for many scientists, we are now being asked to trust a completely opaque process,” says Harvard University epidemiologist Marc Lipsitch, who helped lead a push to require the reviews….

A Harvest of Change in the Heartland

[These excerpts are from an article by Peter Klebnikov in the Winter 2019 issue of Solutions, the newsletter of the Environmental Defense Fund.]

      In American agriculture, corn Is king. More than 89 million acres were planted in 2018, enough to fill a freight train that would more than encircle the earth.

      But growing corn has a steep environ-mental cost. Excess fertilizer runs off fields into rivers, lakes and groundwater, polluting drinking water around the Midwest and creating algae-filled dead zones around the country. It also forms nitrous oxide, a potent greenhouse gas.

      Historically, farmers often didn’t know how much fertilizer to use, so they applied extra to be on the safe side. This hurts downstream communities. Today, farmers increasingly want to use fertilizer more efficiently, which also saves money, and adopt other conservation practices….

      That means partnering with farmers and trade groups to advance practices such as applying fertilizer more precisely, using no-till techniques that leave more carbon in the soil, creating buffers and wetlands along rivers and streams to reduce erosion and improve water quality, and planting cover crops to protect the soil.

      Today’s tech-savvy, data-hungry farmers are using these practices to reinvent their approach to the land….

Getting America Back on Track

[These excerpts are from an article by Charlie Miller in the Winter 2019 issue of Solutions, the newsletter of the Environmental Defense Fund.]

      The state motto is “Land of Enchantment.” New Mexico's high plains, mountains and stunning deserts cast a spell over many visitors. But beyond the scenery lies a dirty secret —a 2,500-square-mile invisible cloud of methane from oil and gas operations hovers over New Mexico’s San Juan Basin, a cloud so enormous that scientists can spot it in infrared images from space.

      New Mexico’s last governor, Susanna Martinez, had no problem with this. She backed a congressional effort to allow unfettered emissions of methane, a greenhouse gas 84 times more powerful than carbon dioxide. She also vetoed three solar bills that would have nudged the state toward clean energy.

      The state’s new governor, Michelle Lujan Grisham, couldn’t be more different. She is one of many new faces of 2019 who are turning the page to an era of renewed environmental progress….

      In some races, climate was an explicit issue. Sean Casten is a writer, scientist and clean energy entrepreneur. He defeated an 11-year incumbent representing suburban Chicago who called climate change “junk science.” Casten put climate change at the heart of his campaign.

      In a Florida district spanning the Everglades and the Florida Keys—both areas highly vulnerable to climate change—the candidates, Democrat and Republican, even released dueling television ads over who was tougher on climate….

      The implications of a more environmentally friendly Congress are profound. Bills that would harm the environment, such as proposed legislation to eviscerate the Endangered Species Act and slash environmental protection budgets, are now nonstarters. And environmental supporters in Congress can now fend off moves to defend critical programs and agencies. And although the Trump administration will still try to roll back key safeguards, it no longer has a completely free hand.

      A disturbing hallmark of the Trump administration has been its unrelenting attacks on science, with climate denial at the center. One proposal now under consideration at Trump’s EPA would invalidate many studies that underpin key public health protections. Supporters of sound science can now push back.

      The House Science Committee is now led by Rep. Eddie Bernice Johnson, elected in 1992 and the first registered nurse to serve in Congress. As chair, she replaced retiring Rep. Lamar Smith, who often brought climate deniers to testify before the committee….

      A comprehensive carbon bill isn’t likely to pass in this Congress, but these are building years to get a strong, bipartisan law passed after 2020. Already, three House committees have announced climate change hearings. We expect House leaders to revive the House Select Committee on Climate Change, which through hearings can draw attention to the issue. With so many new members in Congress, this committee can also educate House newcomers on the dangers of climate change through the testimony of credible experts and scientists, instead of industry shills….

      A critical role for Congress is to provide oversight of the executive branch, a role largely abdicated in the past two years. Acting EPA Administrator Andrew Wheeler will be summoned to appear before Congress to testify under oath about why, for example, he is promoting a sham Clean Power Plan that will do almost nothing to halt climate change.

      Wheeler will face relentless scrutiny of his failure to enforce clean air and clean water rules, as well as the exodus of talented but dispirited staff from the EPA. Many have been handcuffed by political appointees as they try to protect the public from pollution and climate change….

      Victories for the environment extended far beyond Washington, D.C., on Election Day. hi seven states, gubernatorial candidates promising strong climate action won their races. Six more state legislatures now have a majority supporting climate action, and more than 300 state House and Senate seats flipped….

Hope Arrives on Fragile Wings

[These excerpts are from an article by Tasha Kosviner in the Winter 2019 issue of Solutions, the newsletter of the Environmental Defense Fund.]

      It weighs less than a dollar bill and is capable of flying 2,500 miles. The beguiling strength and fragility of the monarch butterfly has captured American hearts. But in the past 30 years, loss of habitat has seen the butterfly’s population plummet 95 percent. It faces an Endangered Species Act listing decision this year.

      Last summer, on a vibrant prairie near Greenville, Missouri, thousands of monarchs seemed to defy this bleak outlook. They flitted between native flowers, fueling up for an extraordinary migration that would carry them across the Great Plains to Mexico….

      It’s hard to imagine that just a few years ago, this was degraded pasture, a monoculture of nonnative grass with L no monarchs and little ecological value….

      Saving the beloved butterfly and supporting renewable energy are not the only benefits. The presence of monarchs and other pollinators such as bees and birds is a key indicator of the health of the land. Restored prairie, rich in native flora, is an ecological powerhouse. It sequesters carbon, prevents soil erosion, retains water and absorbs excess fertilizer, keeping waterways clean….

A Plan to Rescue the Amazon

[These excerpts are from an article by Tasha Kosviner in the Winter 2019 issue of Solutions, the newsletter of the Environmental Defense Fund.]

      …Tropical forest loss is responsible for 16-19 percent of global climate emissions—more than all the world’s cars and trucks combined. In the Amazon, where 95 percent of deforestation is caused by farming, scientists estimate that once 20-25 percent of the forest is destroyed, it will reach a tipping point. After this, damage to the water cycle and resulting reductions in rainfall mean the forest will begin degrading on its own. Currently we are at 19 percent.

      …But we have a steep climb ahead. In 2018, Brazil reported the worst annual deforestation rates in a decade. And in October, Jair Bolsonaro, the country’s new populist president, sailed to victory Among his campaign pledges was a promise to open up forests on indigenous lands to mining and agriculture.

      The news is bleak. But there are some reasons for hope. Caio Penido is one of those reasons. He has ended deforestation on his ranch, leaving more than 5,000 acres of forest intact. By planting more nutritious grasses and practicing better land management he has been able to increase the number of cows per hectare, growing his business without clearing more land. Elsewhere in Mato Grosso similar projects are unfolding, increasing profitability while reducing emissions and saving forests. The Novo Campo project in the Alta Floresta region has assisted a group of beef ranchers to reduce climate emissions associated with beef production by 60 percent. The project will expand to cover 250,000 acres in the next four years.

      …the state—which produces 30 percent of Brazil’s soy and is home to more than 30 million cattle—has committed to ending illegal deforestation by 2020. To achieve this, it has partnered with local producers, communities and environmental organizations to help coordinate and fund initiatives that increase productivity while reducing deforestation….

      The proof is in the numbers. If it were a country, Mato Grosso would have been the world’s fifth-largest greenhouse gas emitter in 2004. By 2014 it would have been 50th. If it stays on track, it could cumulatively reduce emissions by more than six gigatons—that’s nearly the annual emissions of the U.S.—by 2030….

      Success ultimately will depend on local buy-in. In the lush Araguaia Valley, Caio Penido has enlisted 70 other ranchers to comply with Brazil’s forest laws, conserving 160,000 acres of forest while still intensifying production. The ranchers’ efforts will cut carbon emissions by half a million tons by next year….

Gut Bacteria Linked to Mental Well-being and Depression

[These excerpts are from an article by Elizabeth Pennisi in the 8 February 2019 issue of Science.]

      Of all the many ways the teeming ecosystem of microbes in a person’s gut and other tissues might affect health, its potential influences on the brain may be the most provocative. Now, a study of two large groups of Europeans has identified several species of gut bacteria that are largely missing in people with depression. The researchers can’t say whether the absence is a cause or an effect of the illness, but they showed that many gut bacteria could make or break down substances that affect nerve cell function—and maybe mood.

      …took a closer look at 1054 Belgians they had recruited to assess a “normal” microbiome. Some in the group-173 in total—had been diagnosed with depression or had done poorly on a quality of life survey, and the team compared their microbiomes with those of other participants.

      Two kinds of bacteria, Coprococcus and Dialister, were missing from the microbiomes of the depressed subjects, but not from those with a high quality of life. The finding held up when the researchers allowed for factors such as age, sex, or antidepressant use, all of which influence the microbiome, the team reports this week in Nature Microbiology. And when the team looked at another group-1064 Dutch people whose microbiomes had also been sampled—they found the same two species were missing in depressed people, and they were also missing in seven subjects suffering from severe clinical depression. The data don’t prove causality, Raes says, but they are “an independent observation backed by three groups of people.”

      Looking for something that could link microbes to mood, Raes and his colleagues compiled a list of 56 substances important for proper nervous system function that gut microbes either produce or break down. They found that Coprococcus seems to make a metabolite of dopamine, a brain signal involved in depression, although it’s not clear whether the bacteria break down the neurotransmitter or whether the metabolite has its own function. The same microbe makes an anti-inflammatory substance called butyrate; increased inflammation may play a role in depression. (Depressed subjects also had an increase in bacteria implicated in Crohn disease, an inflammatory disorder.)

      Linking the bacteria to depression “makes sense physio-logically….” Still, no one has shown that microbial compounds in the gut influence the brain. One possible channel is the vagus nerve, which links that organ and the gut.

      Resolving the microbiome-brain connection “might lead to novel therapies,” Raes suggests. Some physicians are already exploring probiotics—oral bacterial supplements—for depression, although most don't include the missing gut microbes identified in the new study….

Learning to Think

[These excerpts are from an editorial by Steve Metz in the February 2019 issue of The Science Teacher.]

      We are bombarded daily by a barrage of claims and counter-claims. Cable news commentary, social media, and partisan political pronouncements routinely ask us to accept opinion masquerading as fact, presented alongside data that is often misleading, out of context, or even patently false. Has there ever been a greater need for the rigorous, evidence-based critique of ideas?

      In an age where facts must compete with “alternative facts,” it is more important than ever for our students to learn and practice the skills of scientific argumentation. Taken from the Latin arguer—to make bright or enlighten—argument is central to scientific progress….

      When students defend and critique scientific explanations, experimental designs, or engineering solutions, they learn to create and evaluate arguments using evidence and logical reasoning. Through critical discourse, they are challenged to distinguish opinion from evidence. They learn that argumentation is how scientists collaboratively construct and revise scientific knowledge.

      Argumentation requires students to engage in a social process as they consider competing ideas from multiple voices and generate knowledge through peer-to-peer interaction. They develop the important skill of respectfully considering more than one competing idea. Creating multiple opportunities for students to engage in argumentation can thus promote equity in a classroom where all ideas are valued and the whole class works together in the evaluation and revision of diverse ideas and sources of evidence.

      Perhaps most importantly, argumentation and critique help students learn life skills that extend far beyond the science classroom. Students develop the understanding that claims must be supported by evidence and sound reasoning, not by opinion, belief, emotion, or appeals to authority. Evidence-based argumentation and critique are our only defense against prejudice, pseudoscience, and demagoguery.

Algae Suggest Eukaryotes Get Many Gifts of Bacteria DNA

[These excerpts are from an article by Elizabeth Pensini in the 1 February 2019 issue of Science.]

      Algae found in thermal springs and other extreme environments have heated up a long-standing debate: Do eukaryotes—organisms with a cell nucleus—sometimes get an evolutionary boost in the form of genes transferred from bacteria? The genomes of some red algae, single-celled eukaryotes, suggest the answer is yes. About 1% of their genes have foreign origins, and the borrowed genes may help the algae adapt to their hostile environment….

      Many genome studies have shown that prokaryotes—bacteria and archaea—liberally swap genes among species, which influences their evolution. The initial sequencing of the human genome suggested our species, too, has picked up microbial genes. But further work demonstrated that such genes found in vertebrate genomes were often contaminants introduced during sequencing.

      …any such transfers only occurred episodically—early in the evolution of eukaryotes, as they internalized the bacteria that eventually became organelles such [as] mitochondria or chloroplasts….

In Hot Water

[These excerpts are from an article by Warren Cornwall in the 1 February issue of Science.]

      …The data, collected by research trawlers, indicated cod numbers had plunged by 70% in 2 years, essentially erasing a fishery worth $100 million annually. There was no evidence that the fish had simply moved elsewhere. And as the vast scale of the disappearance became clear, a prime suspect emerged: “The Blob.”

      In late 2013, a huge patch of unusually warm ocean water, roughly one-third the size of the contiguous United States, formed in the Gulf of Alaska and began to spread. A few months later, Nick Bond, a climate scientist at the University of Washington in Seattle, dubbed it The Blob. The name, with its echo of a 1958 horror film about an alien life form that keeps growing as it consumes everything in its path, quickly caught on. By the summer of 2015, The Blob had more than doubled in size, stretching across more than 4 million square kilometers of ocean, from Mexico’s Baja California Peninsula to Alaska’s Aleutian Islands. Water temperatures reached 2.5°C above normal in many places.

      By late 2016, the marine heat wave had crashed across ecosystems all along North America’s western coast, reshuffling food chains and wreaking havoc. Unusual blooms of toxic algae appeared, as did sea creatures typically found closer to the tropics….Small fish and crustaceans hunted by larger animals vanished. The carcasses of tens of thousands of seabirds littered beaches. Whales failed to arrive in their usual summer waters. Then the cod disappeared.

      The fish “basically ran out of food,” Barbeaux now believes. Once, he didn’t think a food shortage would have much effect on adult cod, which, like camels, can harbor energy and go months without eating. But now, it is “something we look at and go: ‘Huh, that can happen.’”

      Today, 5 years after The Blob appeared, the waters it once gripped have cooled, although fish, bird, and whale numbers have yet to recover. Climate scientists and marine biologists, meanwhile, are still putting together the story of what triggered the event, and how it reverberated through ecosystems. Their interest is not just historical.

      Around the world, shifting climate and ocean circulation patterns are causing huge patches of unusually warm water to become more common, researchers have found. Already, ominous new warm-patches are emerging in the North Pacific Ocean and elsewhere, and researchers are applying what they've learned from The Blob to help guide predictions of how future marine heat waves might unfold. If global warming isn’t curbed, scientists warn that the heat waves will become more frequent, larger, more intense, and longer-lasting. By the end of the century, Bond says, “The ocean is going to be a much different place.”

      …The Blob was spawned, experts say, by a long-lasting atmospheric ridge of high pressure that formed over the Gulf of Alaska in the fall of 2013. The ridge helped squelch fierce winter storms that typically sweep the gulf. That dampened the churning winds that usually bring colder, deeper water to the surface, as well as transfer heat from the ocean to the atmosphere—much like a bowl of hot soup cooling as a diner blows across it. As a result, the gulf remained unusually warm through the following year.

      But it took a convergence of other forces to transform The Blob into a monster. In the winter of 2014-15, winds from the south brought warmer air into the gulf, keeping sea temperatures high. Those winds also pushed warm water closer to the coasts of Oregon and Washington. Then, later in 2015 and in 2016, the periodic warming of the central Pacific known as El Nino added more warmth, fueling The Blob’s growth. The heat wave finally broke when La Nifia—El Nino’s cool opposite number—arrived at the end of 2016, bringing storms that stirred and cooled the ocean….

      Krill—tiny shrimp that, like copepods, are a key food for many fish—felt the heat, too. In 2015 and 2016, as The Blob engulfed the coasts of Washington and Oregon, the heat-sensitive creatures vanished from biologists’ nets.

      As the base of the food chain crumbled, the effects propagated upward. One link higher, swarms of small fish that dine on copepods and krill—and in turn become food for larger animals—also became scarce as warm waters spread. On a remote island in the northern gulf, where scientists have tracked seabird diets for decades, they noticed that capelin and sand lance, staples for many bird species, nearly vanished from the birds' meals. In 2015, by one estimate, the populations of most key forage fish in the gulf fell to less than 50% of the average over the previous 9 years….

Democracy’s Plight

[These excerpts are from an editorial by Rush Holt in the 1 February 2019 issue of Science.]

      Scientists work with a deep sense that their quest for reliable knowledge leads somewhere—that following the evidence and excluding bias help to make sense of the world. It may be a slow process, and interactions in the scientific community are not without friction and false steps, yet scientists are devoted to the quest because they observe that it works. One can make sense of the world. Einstein famously said, “the eternal mystery of the world is its comprehensibility,” and scientists understand that evidence-based scientific thinking leads to this comprehension. Scientists could do a better job of sharing this powerful insight.

      …Observers speak of “truth decay,” dismissal of expertise, and neglect of evidence. Collectively, these are problems of enormous importance because they threaten democracy itself. Democracy is at risk when it becomes simply a contest of fervently held opinions or values not grounded in evidence. When one opinion is as good as another—each asserted as strongly, and even as deceptively, as possible—democracy cannot survive. Society is drowning in a sea of unmoored opinons and values. Democracy requires a citizenry that is informed, as well as engaged. We must find an opening to reinforce among citizens a renewed appreciation for evidence. Approaching an understanding of the actual state of things is what science does well.

      In the United States, the public's approval and trust in science are relatively strong compared with other institutions, a finding that has been observed in public surveys for decades. Here, then, may be an opening. Can scientists share the admired successes of science in a manner that leads citizens to embrace for themselves the essence of science? This essence of science is to demand evidence at every turn and to discard ideas when they are shown not to comport with the evidence. This thinking is not reserved solely for scientists, and one need not be an expert to demand evidence. Given the public's respect for science and science’s reverence for evidence, can the public be moved to demand and embrace evidence for themselves? This connection seems logical—we need to make it feasible. Can scientists achieve what normal civic education has not achieved? There is no time to waste in finding this out.

From Competition to Collaboration

[These excerpts are from an op-ed article by Giovanni Camanni in the 25 January 2019 issue of Science.]

      It was just like any other morning. I was at the bus stop, on my way to the lab where I was a post-doctoral fellow. But as I watched the people around me—headphones dangling from their ears, eyes cast down, unsmiling faces—something began to stir inside me. They looked unhappy. And, I realized, I was one of them. Suddenly, I could no longer continue with my work life. I turned around, went back to my flat, and booked a one-way ticket to fly home the next morning. I didn’t know how long I would be away or what would come next. All I knew was that, even though I loved science and research, what I had been doing wasn’t working.

      Over the years, as I dealt with the pressures of finishing my Ph.D. and securing and starting my post-doc, I had grown more competitive. To prove that I was a valuable researcher, I pushed myself to be the first to generate sensational results and to publish in high-impact journals. Those who could have been collaborators became rivals I resented.

      But the effect of this competitive streak was exactly the opposite of what I had hoped for. The pressure became overwhelming. When I encountered scientific problems, I thought I had to solve them myself instead of asking for help. I began to feel alone and lost. I became less and less productive. But the culture of academia—prizing competition and individual successes above all else—seemed to reinforce my approach. I was sure that this was not the right time to show any insecurities, so I persevered.

      That day at the bus stop, I hit my breaking point. The race had to end….

      Three months after I left so suddenly, I was prepared to go back to work. I was excited to get back to the science that I loved, and I now had a foundation to be more open with my colleagues. I understood that we all struggle sometimes, and that vulnerability and collaboration can be more powerful than competition. It doesn’t have to be a zero-sum game.

      The first days were difficult. I had naively thought that, right away, everything would be different. But as soon as I was back in that workplace, I felt the stirrings of that old competitiveness. I focused on maintaining my new perspective and being patient as I readjusted. With a bit of time, I understood that, although the place and position were the same, I had changed. I hadn't just accepted my vulnerability; I had embraced it and opened up about it to my colleagues.

      As a result, collaboration has replaced competition. Working with others and seeking help doesn’t diminish my value or contributions; it means we can all win. Now, when I encounter problems in my work, I frequently discuss them with colleagues, knowing that considering multiple points of view often leads to solutions. I have become more productive. Working relationships are now genuine human ones. I no longer feel like one of the lonely, unhappy people at the bus stop.

Light Skin May Be Legacy of Native American Ancestors

[These excerpts are from an article by Lizzie Wade in the 25 January 2019 issue of Science.]

      Walk down a busy street in most Latin American cities today and you’ll see a palette of skin colors from dark brown to sepia to cream. For 500 years, people have assumed this variation comes from the meeting and mixing of Native Americans, Europeans, and Africans during colonial times and later. People with lighter skin are thought to have more European ancestry, whereas those with darker skin are taken to have more Native American or African ancestry—and are often targeted for discrimination.

      Now, a new study of the genes of more than 6000 people from five Latin American countries undercuts the simplistic racial assumptions often made from skin color. An international team discovered a new genetic variant associated with lighter skin found only in Native American and East Asian populations. That means that in Latin America, lighter skin can reflect Native American as well as European ancestry….

      Latin America is fertile ground for such studies. People there often have Native American, European, and African ancestors, and because Native American populations are closely related to those from East Asia, researchers can also spot East Asian variants in Latin American genomes….

      …People at high latitudes in Europe and East Asia seem to have independently evolved lighter skin to produce vitamin D more efficiently with less sunlight….

      The larger lesson…is the pitfalls of a Eurocentric view "Our study shows that going beyond Europeans one can find additional genes, even for well-studied traits. Clearly the bias towards Europeans has led to a restricted view of human diversity."

Where to Find Fantastic Beasts at Sea

[These excerpts are from an article by Nicholas D. Pyenson in the 25 January 2019 issue of Science.]

      The biggest predators in the oceans captivate us for good reasons: Sharks, billfishes, whales, and penguins have big appetites, range over large distances, and have achieved similar body forms from vastly different starting points on the tree of life. Evolutionary convergences among large marine predators are also more than skin deep; those with ancestries on land, such as marine mammals and seabirds, have independently evolved an array of molecular and tissue specializations for maximizing oxygen and warmth. Beyond these fantastic traits, marine predators also possess large body sizes and trophic linkages that make them ecologically important consumers in marine food webs….

      Macroecologists who study marine predators have long known that convergences in form do not yield similar ecological distributions over geographic space. Most marine mammal species occur at higher latitudes, whereas sharks and fishes are found closer to the equator. Endothermic marine mammals are also most plentiful in polar and temperate seas. This latitudinal distribution contrasts with that of nearly every other marine animal group, which shows peaks in equatorial to temperate seas. Why the difference?...a possible answer: A fundamental asymmetry in metabolism gives endotherms an advantage when hunting in colder, more prey-rich waters.

      …The basic distribution maps show startling gaps in top predator occupancy across the globe. For example, there is a lack of marine mammals in the Indo-Australian Archipelago, despite this region being an epicenter for marine biodiversity….

      Explaining this geographic pattern requires revisiting the models that describe the cost-benefit trade-offs of top predators feeding on their prey. On first principles alone, individual endothermic predators maintain consistent metabolism across latitudes, whereas the metabolism of ectotherms plummets in colder waters, which would affect relative foraging performance. Scaling up to the ecosystem level, where prey production is relatively uniform, each endothermic and ectothermic predator species should have strongly differential consumption rates across latitudes—all driven by water temperature as a primary structuring factor….

Oldest Images of Dogs Show Hunting, Leashes

[These excerpts are from an article by David Grimm in the 17 November 2018 issue of Science.]

      Carved into a sandstone cliff on the edge of a bygone river in the Arabian Desert, a hunter draws his bow for the kill. He is accompanied by 13 dogs, each with its own coat markings; two animals have lines running from their necks to the man's waist.

      The engravings likely date back more than 8000 years, making them the earliest depictions of dogs, a new study reveals. And those lines are probably leashes, suggesting that humans mastered the art of training and controlling dogs thousands of years L earlier than previously thought….

      The hunting scene comes from Shuwaymis, a hilly region of northwestern Saudi Arabia where seasonal rains once formed rivers and supported pockets of dense vegetation….

      Starting about 10,000 years ago, hunter-gatherers entered—or perhaps returned to—the region. What appear to be the oldest images are thought to date to this time and depict curvy women. Then about 7000 to 8000 years ago, people here became herders, based on livestock bones found at Jubbah; that's likely when pictures of cattle, sheep, and goats began to dominate the images. In between—carved on top of the women and under the livestock—are the early hunting dogs: 156 at Shuwaymis and 193 at Jubbah. All are medium-sized, with pricked up ears, short snouts, and curled tails—hallmarks of domestic canines. In some scenes, the dogs face off against wild donkeys. In others, they bite the necks and bellies of ibexes and gazelles. And in many, they are tethered to a human armed with a bow and arrow.

      …the engravings may not be as old as they seem. To confirm the chronology, scientists will need to link the images to a well-dated archaeological site—a challenge, she says, because “the archaeological record in this region is really spotty.”

Beyond Plastic Waste

[These excerpts are from an editorial by Dame Ellen MacArthur in the 17 November 2018 issue of Science.]

      With more than 8 million tons of plastic entering the ocean each year, humanity must urgently rethink the way we make and use plastics, so that they do not become waste in the first place.

      Cheap, light, and versatile, plastics are the dominant materials of our modern economy. Their production is expected to double over the next two decades. Yet, only 14% of all plastic packaging is collected for recycling after use, and vast quantities escape into the environment. This not only results in a loss of $80 billion to $120 billion per year to the global economy, but if the current trend continues, there could be more plastic than fish by weight in the oceans by 2050.

      Some companies have started changing their habits. Unilever, for example, has promised that by 2025, all its plastic packaging will be fully reusable, recyclable, or compostable in a commercially viable manner. Given that up to a third of all plastic packaging items are too small (such as straws and sachets) or too simplex (such as multimaterial films and take-away coffee cups) to be economically recycled, achieving these commitments will require a great degree of redesign and innovation.

      Such company commitments and innovations are a step in the right direction. But creating a plastics system that works will require collaboration among all participants in the plastics sector….

      …Bans on or charges for single-use shopping bags have, for example, led to rapid reductions in their use in France, Rwanda, and the United Kingdom. A few uncommon types of plastic used in packaging are too expensive to recycle and should be phased out. A science-based approach is needed to replace chemicals such as endocrine disruptors that are found in some plastics and pose a risk to human health.

      Such restrictions need to be complemented by mechanisms that foster innovation. Policy-makers can connect the design of plastic packaging with its collection, sorting, and subsequent reuse, recycling, or composting by supporting deposit-refund schemes for drinks bottles, as in Germany and Denmark, or by requiring producers to consider what happens to their packaging products after use. A useful policy approach is extended producer responsibility (EPA), which makes producers responsible for the entire product life cycle. EPR policies have been introduced in European Union legislation and at the national level for packaging, batteries, vehicles, and electronics. Such policies can support good design and improve the economics of after-use options for packaging materials.

      However, the most potent tool for policy-makers remains the setting of a clear common vision and credible high-level ambitions that drive investment decisions. In the case of plastics, a crucial pillar of such a policy ambition must be stimulating scientific breakthroughs in the development of materials that can be economically reused, recycled, or composted….

Massive Fish Die-off Sparks Outcry in Australia

[These excerpts are from an article by Dennis Normile in the 25 January 2019 issue of Science.]

      Australians knew another long drought was hammering the country’s southeast. But it took a viral Facebook video posted on 8 January to drive home the ecological catastrophe that was unfolding in the Murray-Darling river system. In the footage, Rob McBride and Dick Arnold, identified as local residents, stand knee-deep among floating fish carcasses in the Darling River, near the town of Menindee. They scoff at authorities’ claims that the fish die-off is a result of the drought. Holding up an enormous, dead Murray cod, a freshwater predator he says is 100 years old, McBride says: “This has nothing to do with drought, this is a manmade disaster.” Arnold, sputtering with rage, adds: “You have to be bloody disgusted with yourselves, you politicians and cotton growers.”

      Scientists say McBride probably overestimated the age of the fish. But they agree that the massive die-off was not the result of drought….

      Excessive water use has left river flows too low to flush nutrients from farm runoff through the system, leading to large algal blooms, researchers say. A cold snap then killed the blooms, and bacteria feeding on the dead algae sucked oxygen out of the water, suffocating between 100,000 and 1 million fish. The death of so many individuals that had survived previous droughts is “unprecedented,” says ANU ecologist Matthew Colloff. And with fish of breeding age decimated, recovery will be slow. “But only a bloody fool would put a time frame on that,” Colloff says.

      This wasn’t supposed to happen. In 2012, the national government adopted the Murray-Darling Basin Plan, touted as a “historic” deal to ensure that enough water remained in the rivers to keep the eco-system healthy even after farmers and households took their share….

      The 1-million-square-kilometer Murray-Darling Basin accounts for 40% of Australia’s agricultural output, thanks in part to heavy irrigation. By the early 2000s, water flows in the lower reaches of the basin were just a third of historical levels, according to a 2008 study. During the millennium drought, which started in the late 1990s and lasted for a decade, downstream communities faced water shortages.

      In 2008, the federal government created the Murray-Darling Basin Authority to wrestle with the problem. In 2010, a study commissioned by the authority concluded that farmers and consumers would have to cut their use of river water by at least 3000 but preferably by 7600 gigaliters annually to ensure the health of the ecosystem. Farmers, who saw their livelihoods threatened, tossed the report into bonfires.

      The final plan, adopted as national law in 2012, called for returning just 2750 gigaliters to the rivers, in part by buying water rights back from users….

      Implementation has exacerbated the problems. Since 2012, the federal government has spent AU$6 billion on the plan, but two-thirds has gone to improving irrigation infrastructure, on the premise that efficiency would ease demands on the rivers. Critics say the money would have been better spent on purchasing water rights.

      Grafton says there are also suspicions of widespread water theft; up to 75% of the water taken by irrigators in the northern part of the system is not metered. Farmers are also now recapturing the runoff from irrigated fields that used to flow back into streams, and are increasing their use of ground water, leaving even less water in the system….

      In February 2018, such issues prompted a group of 12 academics, including scientists and policy experts, to issue the Murray-Darling Declaration. It called for independent economic and scientific audits of completed and planned water recovery schemes to determine their effects on stream flows. The group, which included Williams and Grafton, also urged the creation of an independent, expert body to provide advice on basin water management. Young, who wasn't on the declaration, wants to go further and give that body the power to manage the basin’s water, the way central banks manage a country’s money supply, using stream levels to determine weekly irrigation allocations and to set minimum flow levels for every river.

      Before the fish kill, such proposals had garnered little attention. But Young hopes the public outrage will influence federal elections that have to take place by mid-May….

Bearing Witness

[These excerpts are from an article by Douglas Starr in the 25 January 2019 issue of Science.]

      In a St. Louis, Missouri, courtroom last summer, David Egilman testified in a lawsuit filed by 22 women who claimed to have contracted ovarian cancer from exposure to Johnson & Johnson (J&J) baby powder. Like millions of women before them, they had dusted their babies with the powder and used it on themselves thousands of times. They alleged the talc was tainted with asbestos and that exposure to the carcinogenic fiber likely played a role in their cancers.

      Egilman, a professor of family medicine at Brown University who served as a paid expert witness, brought science and medical gravitas to his testimony. He interviewed the women about their frequency and duration of talc use, and he factored in the levels of asbestos that outside scientists had found in samples of talc, which is sometimes mined from formations that also yield asbestos. From those data, he said, he could calculate the women’s doses of the carcinogen, and he argued that their exposure had doubled their risk of ovarian cancer.

      J&J had its own experts, who said the talc was asbestos-free and there was no proof that the product caused cancer. But Egilman’s decisive contribution may have come from his scrutiny of company documents. After examining thousands of pages of internal J&J documents unearthed during the litigation, he and his student researchers concluded that J&J found no asbestos in the talc because its tests were not sensitive enough. He compared the company's methods to trying to weigh a needle on a bathroom scale.

      …(Since the trial, other internal J&J documents have become public, which show the company knew about the asbestos contamination for decades but suppressed the information.)

      Egilman believes corporations have minimized their costs at the expense of their employees’ health and that of the public and the environment—and that recent weakening of regulations has made that problem worse. He sees speaking out in court as a mission. “As a doctor, I can treat one cancer patient at a time,” he explained during a trial last year. “But by being here, I have the potential to save millions.” More broadly, he says corporate money and power have intimidated scientists and corrupted science itself—a concern that has led him into battle not only with corporations, but also with journals that publish what he describes as tainted results.

      In 35 years as an expert witness, he has given depositions and testimony in more than 600 cases of occupational or environmental disease. He has helped win billions of dollars for injured or sick workers or consumers, or for the families of those who have died. By his reckoning, he has earned more than $5 million for such legal work; he says he has donated some of his fees to charities, including a nonprofit he founded to improve health in developing countries.

      Specializing in occupational lung disease, Egilman diagnoses patients and marshals data. But he also digs into corporate records uncovered during litigation, invariably finding memos and studies showing that com-panies knew about industrial hazards long before warning employees or the public….

      Egilman’s sense of mission propels a prodigious work ethic—by his own estimate, he works 100 to 120 hours per week—and some-times emboldens him to act rashly. In 2007, patients were suing Eli Lilly and Company, claiming that its antipsychotic medicine olanzapine (Zyprexa) had caused dramatic weight gain and diabetes. Reviewing company documents as an expert witness for the plaintiffs, Egilman found emails implying Eli Lilly knew of the danger but long tried to play it down. The judge ordered that the documents be kept confidential to protect the company’s proprietary sales and marketing strategies, but Egilman leaked them to a New York Times reporter. “A physician’s oath never says to keep your mouth shut,” Egilman says.

      The court was not amused by that “brazen breach” of protocol. “They could have put me in jail,” Egilman says. To avoid criminal charges, he paid a $100,000 settlement. But after the newspaper story ran, 30 states subpoenaed documents on Eli Lilly's sales and marketing activities, showing the same incriminating behavior. In 2009, it agreed to pay $1.4 billion to settle criminal cbarges and civil suits….

Nuclear Power and Promise

[These excerpts are from a book review by Jacob Darwin Hamblin in the 18 January 2019 issue of Science.]

      Less than a year after the Fukushima nuclear accident in Japan, physicist Gregory B. Jaczko tried to break the “first commandment” of nuclear regulation: Thou shalt not deny a license to operate a reactor. As chairman of the U.S. Nuclear Regulatory Commission (NRC), he knew that the tradition was to encourage doomed applications to be withdrawn. But when one company refused, Jaczko dug in his heels and opposed the license. It turned out to be a futile gesture that the other commissioners opposed. But it was one of many examples, he contends, of the weaknesses in the nation’s top nuclear regulatory body and an exemplar of its obeisance to the nuclear power industry.

      Confessions of a Rogue Nuclear Regulator is one part engrossing memoir and another part seething diatribe, depicting a government agency that routinely caves to industry pressure….

      …The ensuing political fracas convinced Jaczko that the nuclear industry used the NRC as a tool for promoting rather than regulating nuclear power. He believes that a national repository for radioactive waste puts too much responsibility on the taxpayer….

      The answer is to stop producing nuclear waste, argues Jaczko, and indeed stop producing nuclear power at all. He wishes that as chairman, he’d “had the courage to say this, but my courage had its limits.”

      Most of Jaczko’s short book hammers on the theme that industry lobbyists hold sway over the would-be regulators. He highlights the longstanding concept of “enforcement discretion” and skewers it as one of nuclear regulation’s “greatest oxymorons.”

      Rather than demand safety compliance, the NRC historically has allowed nuclear plants to develop alternative approaches and has granted exceptions and exemptions. Recounting an episode in which he tried to abolish enforcement discretion in fire safety, Jaczko writes: “What happened over the next several weeks was more brutal than Roman imperial succession.”

      The political infighting was particularly intense after the 2011 Fukushima disaster. Jaczko visited Japan and grew impatient with the "litany of guarantees" from industry about American nuclear facilities. He tried to insist on new requirements to mitigate accidents triggered by natural disasters such as floods, earthquakes, and tsunamis. One internal NRC report drafted after Fukushima criticized the practice of relying on voluntary industry initiative to address safety concerns. Jaczko’s descriptions of other commissioners’ attempts to quash or edit the report provide a disturbing glimpse of the dynamic of trust and betrayal within the agency….

Flotilla Launches Large Survey of Antarctic Krill

[These excerpts are from an article by Erik Stokstad in the 18 January 2019 issue of Science.]

      Krill, crustaceans smaller than a cigarette, play an outsize role in the ecology of the ocean around Antarctica: Penguins, whales, and other predators feast on vast swarms of the shrimplike animals. Now, researchers have launched a broad international survey of krill’s main habitat in and around the Scotia Sea—the first in nearly 20 years—to learn whether a growing fishing industry is leaving enough for krill’s Lnatural predators….

      Soviet vessels were the first to ply the Southern Ocean for krill, which was ground into fish meal. By the 1980s, scientists began to worry about the effect on krill-feeding predators. The Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), a treaty organization established in 1982, set tight limits on fishing, now at 620,000 tons per year. Most fishing stopped after the 1991 collapse of the Soviet Union, but it has been slowly growing again. Norway takes about half the current catch, extracting omega-3 fatty acids for nutritional supplements….

      During the survey, vessels will retrace the previous transects, measuring krill swarms with echosounders, a kind of sonar, and confirming the identification with sampling trawls. Some ships will measure oceanographic variables as well, such as temperature, currents, and plankton, to see whether they can be used to predict krill abundance….

      The survey itself won't be able to reveal how the overall krill population in the Scotia Sea might have changed since the 2000 survey, given the variability of krill populations over space and time. Finding out what drives population changes will require more research on the seasonal movement of krill, for example, and the impact of climate change. Loss of sea ice, which protects young krill from predators, is expected to reduce their abundance, and rising water temperatures and acidification could also pose serious threats—ones that even the best management plan might not avert.

Did Neurons Arise from an Early Secretory Cell?

[These excerpts are from an article by Elizabeth Pennisi in the 18 January 2019 issue of Science.]

      Swimming through the oceans, voraciously consuming plankton and other small creatures—and occasionally startling a swimmer—the beautiful gelatinous masses known as comb jellies won’t be joining Mensa anytime soon. But these fragile creatures have nerve cells—and they offer insights about the evolutionary origins of all nervous systems, including our own. Inspired by studies of a glue-secreting cell unique to these plankton predators, researchers have now proposed that neurons emerged in the last common ancestor of today’s animals—and that their progenitors were secretory cells, whose primary function was to release chemicals into the environment….

      Today, nerve cells are among the most specialized cell types in the body, able to transmit electrical signals, for example. Some versions talk to each other, others relay information from the environment to the brain, and still more send directives to muscles and other parts of the body. They are an almost universal feature of animals; only sponges and placozoans, an obscure group of tiny creatures with the simplest of animal structures, lack them….

      When and how the animal nervous sys-em arose has remained murky; however….

Why We Need Fetal Tissue Research

[These excerpts are from an editorial by Sally Temple and Lawrence S.B. Goldstein in the 18 January 2019 issue of Science.]

      A vocal minority in the United States is intent on stopping federal funding for research using human fetal tissue, citing stem cell-based or other alternatives as adequate. This view is scientifically inaccurate. It ignores the current limitations of stem cell research and disregards the value of fetal tissue research in finding therapies for incurable diseases. If there is to be continued rapid progress in treating cancer, birth defects, heart disease, and infectious diseases, then we need fetal tissue research.

      Life-saving advances, including the development of vaccines against rubella, rabies, and hepatitis A viruses, and antiviral drugs that prevent HIV/AIDS, required fetal tissue research. Today, fetal tissue is being used to develop new medicines including vaccines for HIV/AIDS, preventives for Zika virus, and immunotherapies to battle untreatable cancers.

      Although research into alternatives is worthwhile, there are several aspects of fetal tissue research for which alternatives do not and will not exist. For example, to discover which fetal cells go awry and cause childhood cancers such as retinoblastoma, a cancer of the eye, or rhabdomyosarcoma, a muscle cancer, we must understand which cells are the culprits. For that, we need access to relevant fetal tissues. Zika virus can cross the placenta and attack specific fetal brain cells. To determine the mechanism of viral entry, which cell types are vulnerable, and how to prevent infection and damage, we need access to fetal brain tissue. Beyond diseases affecting children, some forms of hereditary Alzheimer’s disease cause neural impairments in utero that persist over decades and manifest later in life. Without access to fetal cells, we cannot understand and effectively combat diseases that begin in utero.

      Fetal tissue alternatives for some applications may be developed as science advances, but this will take time. The transition to any new model of research should be data-driven and based on scientific evidence. Opponents of fetal tissue research state that human stem cell-derived organoids are adequate models, supplanting fetal tissue research, but that is incorrect….

      Although alternatives maybe established in some cases, fetal tissue remains an essential resource for many applications. It is important to remember that the fetal tissue used in research would otherwise be discarded and thus unavailable in the fight against disease. U.S. researchers also follow rigorous, well-established medical and ethical standard practices for this research. Fetal tissue research has been supported for decades by both Republican and Democratic administrations and congresses. Rigorous U.S. government-sponsored review processes have also concluded that this research is ethical and valuable.

The Bones of Bears Ears

[These excerpts are from an article by April Reese in the 18 January 2019 issue of Science.]

      Thousands of such rare fossils pepper Bears Ears, a sweep of buttes and badlands whose candy-striped sedimentary rocks catalog hundreds of millions of years of Earth’s history. The region’s rich paleontological and archaeological record—and the lobbying of southwestern tribes whose ancestors lived here—persuaded former President Barack Obama to designate the area a national monument just over 2 years ago, in the waning days of his administration.

      Now, those fossils, and the influx of special research funding that came with the designation, are under threat. In December 2017, urged on by Utah officials, President Donald Trump slashed the size of the 547,000-hectare monumpt by 85%, leaving just 82,000 hectares split into two separate units. Since Trump’s order took effect in February 2018, the excised lands, which hold thousands of Native American artifacts and sites—and possibly the world’s densest cache of fossils from the Triassic period, roughly 250 million to 200 million years ago—are open again to mining, expanded grazing, and cross-country trekking by off-mad vehicles.

      That prospect spurred the typically apolitical Society of Vertebrate Paleontology (SVP), based in Bethesda, Maryland, to sue the Trump administration in federal court, joining archaeologists, environmentalists, outdoor companies, and five Native American tribes. Their argument: The 1906 Antiquities Act used to create Bears Ears only allows presidents to establish monuments—not to drastically reduce them. The cutbacks represent an “extreme overreach of authority,” SVP said in announcing the lawsuit just days after Trump’s move. If SVP wins, the ruling could set a precedent that would help safeguard the boundaries of the 158 national monuments created under presidential authority; if it loses, future presidents could gain new powers to downsize them.

      …A similarly rich fossil trove, from the era when dinosaurs ruled, helped make the case for that monument, which was established by then-President Bill Clinton in 1996 and cut in half by Trump in another December 2017 proclamation. An influx of federal funding followed, which Polly credits with allowing researchers to uncover some of the world’s best records of the Late Cretaceous.

      Within 10 years, researchers had discovered fossils from 25 taxa new to science and documented the rise of flowering plants, insects, and the ancestors of mammals between 145 million and 66 million years ago….

      Bears Ears’s record begins earlier, more than 340 million years ago, when the supercontinent Pangaea spanned much of the planet. A tropical sea that covered the area began to fill with sediment shed by the uplifting Rocky Mountains, leaving thousands of prehistoric sea creatures, mammallike reptiles, and dinosaurs entombed in hardened mudflats. Some of those fossils help tell the story of the “great dying” 252 million years ago, which killed 96% of marine species and 70% of terrestrial ones, clearing the way for dinosaurs. Others chronicle the End Triassic extinction some 50 million years later, which wiped out 76% Of terrestrial and marine life….

      The loss of monument status means 1 those treasures could be exposed to many dangers. Off-road vehicles are now allowed to crisscross the monument’s former grounds, which are once again open to mining (although new projects must go through ELM’s usual review process). The land will also lose out on resources aimed at beefing up research, such as personnel—Grand Staircase got its own paleontologist, for example—and special funding to develop scientific and cultural resources.

      That money—part of federal funding for BLM lands protected for their scientific resources—not only funds ongoing projects and spurs new discoveries; it also helps ensure that scientists find those resources before looters do. Looting has long been a problem in San Juan County, where the monument is located….

Cheap Oil vs. Climate Change

[This excerpt is from a book report by Miriam R. Aczel in the 11 January 2019 issue of Science.]

      Since the discovery of oil in the 1930s, the six Gulf monarchies—Saudi Arabia, Qatar, Kuwait, Oman, Bahrain, and the United Arab Emirates—have become known for their seemingly endless supply of cheap energy and a growing domestic appetite for it. However, in the face of a changing climate, the very policies that led to their development and prosperity are today posing a threat as the region faces record-breaking temperatures. Jim Krane’s compelling Energy Kingdoms takes readers inside this critical energy conundrum.

      Krane evaluates the forces behind the Gulf region’s “feverish demand for its chief export commodity” and argues that the monarchies’ economic and political systems have created contradictory phenomena: Subsidization of energy; a key political institution, undermines oil and gas exporting, their main economic institution. “[L]ong term, these two crucial components of governance cannot remain in conflict. Either the political structures will bend or the economy will yield.”

How Fast Are the Oceans Warming?

[These excerpts are from an article by Lijing Cheng, John Abraham, Zeke Hausfather and Kevin E. Trenberth in the 11 January 2019 issue of Science.]

      Climate change from human activities mainly results from the energy imbalance in Earth’s climate system caused by rising concentrations of heat-trapping gases. About 93% of the energy imbalance accumulates in the ocean as increased ocean heat content (OHC). The ocean record of this imbalance is much less affected by internal variability and is thus better suited for detecting and attributing human influences than more commonly used surface temperature records. Recent observation-based estimates show rapid warming of Earth’s oceans over the past few decades….This warming has contributed to increases in rainfall intensity, rising sea levels, the destruction of coral reefs, declining ocean oxygen levels, and declines in ice sheets; glaciers; and ice caps in the polar regions. Recent estimates of observed warming resemble those seen in models, indicating that models reliably project changes in OHC….

      The fairly steady rise in OHC shows tha the planet is clearly warming. The prospects for much higher OHC, sea level, and sea-surface temperatures should be of concern given the abundant evidence of effect on storms, hurricanes, and the hydrological cycle, including extreme precipitation events. There is a clear need to continue to improve the ocean observation any analysis system to provide better estimate of OHC, because it will enable more refines regional projections of the future. In addition, the need to slow or stop the rate of climate change and prepare for the ex pected impacts is increasingly evident.

A Fresh Look at Nuclear Energy

[This excerpt is from an editorial by John Parsons, Jacopo Buongiorno, Michael Corradini and David Petti in the 11 January 2019 issue of Science.]

      We are running out of time, as the Intergovernmental. Panel on Climate Change (IPCC) warned last October in a special report, Global Warming of 1.5°C. National commitments under the 2015 Paris Agreement are only the first step toward decarbonization, but most countries are already lagging behind. It is time to take a fresh look at the role that nuclear energy can play in decarbonizing the world's energy system.

      Nuclear is already the largest source of low-carbon energy in the United States and Europe and the second-largest source worldwide (after hydropower). In the September report of the MIT Energy Initiative, The Future of Nuclear Energy in a Carbon-Constrained World, we show that extending the life of the existing fleet of nuclear reactors worldwide is the least costly approach to avoiding an increase of carbon emissions in the power sector. Yet, some countries have prioritized closing nuclear plants, and other countries have policies that undermine the financial viability of their plants. Fortunately, there are signs that this situation is changing. In the United States, Illinois, New Jersey, a and New York have taken steps to preserve their nuclear plants as part of a larger decarbonization strategy. In Taiwan, voters rejected a plan to end the use of nuclear energy. In France, decisions on nuclear plant closures must account for the impact on decarbonization commitments. In the United Kingdom, the government’s decarbonization policy entails replacing old nuclear plants with new ones. Strong actions are needed also in Belgium, Japan, South Korea, Spain, and Switzerland, where the existing nuclear fleet is seriously at risk of being phased out.

      What about the existing electricity sector in developed countries—can it become fully decarbonized? In the United States, China, and Europe, the most effective and least costly path is a combination of variable renewable energy technologies—those that fluctuate with time of day or season (such as solar or wind energy), and low-carbon dispatchable sources (whose power output to the grid can be controlled on demand). Some options, such as hydropower and geothermal energy, are geographically limited. Other options, such as battery storage, are not affordable at the scale needed to balance variable energy demand through long periods of low wind and sun or through seasonal fluctuations, although that could change in the coming decades. Nuelear energy is one low-carbon dispatchable option that is virtually unlimited and available now. Excluding nuclear power could double or triple the average cost of electricity for deep decarbonization scenarios because of the enormous overcapacity of solar energy, wind energy, and batteries that would be required to meet demand in the absence of a dispatchable low-carbon energy source.

      One obstacle is that the cost of new nuclear plants has escalated, especially in the first-of-a-kind units currently being deployed in the United States and Western Europe. This may limit the role of nuclear power in a low-carbon portfolio and raise the cost of deep decarbonization. The good news is that the cost of new nuclear plants can be reduced, not only in the direct cost of the equipment, but also in the associated civil structures and in the processes of engineering, licensing, and assembling the plant….

Seeing the Dawn

[These excerpts are from an article by Robert F. Service in the 11 January 2019 issue of Science.]

      A cataclysm may have jump-started life on Earth. A new scenario suggests that some 4.47 billion years ago—a mere 60 million years after Earth took shape and 40 million years after the moon formed—a moon-size object sideswiped Earth and exploded into an orbiting cloud of molten iron and other debris.

      The metallic hailstorm that ensued likely lasted years, if not centuries, ripping oxygen atoms from water molecules and leaving hydrogen behind. The oxygens were then free to link with iron, creating vast rust-colored deposits of iron oxide across our planet’s surface. The hydrogen formed a dense atmosphere that likely lasted 200 million years as it ever so slowly dissipated into space.

      After things cooled down, simple organic molecules began to form under the blanket of hydrogen. Those molecules, some scientists think, eventually linked up to form RNA, a molecular player long credited as essential for life’s dawn. In short, the stage for life's emergence was set almost as soon as our planet was born.

      …No rocks or other direct evidence remain from the supposed cataclysm….

      The metal-laden rain accounts for the distribution of metals across our planet’s surface today. The hydrogen atmosphere would have favored the emergence of the simple organic molecules that later formed more complex molecules such as RNA. And the planetary crash pushes back the likely birthdate for RNA, and possibly life’s emergence, by hundreds of millions of years, which better aligns with recent geological evidence suggesting an early emergence of life.

      The impact scenario joins new findings from laboratory experiments suggesting how the chemicals spawned on early Earth might have taken key steps along the road to life—steps that had long baffled researchers. Many in the field see a consistent narrative describing how and when life was born starting to take shape….

      The case isn’t settled, Luptak and others say. Researchers still disagree, for example, over which chemical path most likely gave rise to RNA and how that RNA combined with proteins and fats to form the earliest cells….

      Since the 1960s, a leading school of thought has held that RNA arose first, with DNA and proteins evolving later. That’s because RNA can both serve as a genetic code and catalyze chemical reactions. In modern cells, RNA strands still work alongside proteins at the heart of many crucial cellular machines.

      In recent years, chemists have sketched out reactions that could have produced essential building blocks for RNA and other compounds….

The Last Resort

[These excerpts are from an article by Richard Conniff in the January 2019 issue of Scientific American.]

      …In a special report in October 2018, the Intergovernmental Panel on Climate Change warned that we have just 12 years to act if we hope to avoid slipping past 1.5 degrees C, the level regarded by most scientists as the furthest we can go if we hope to preserve life more or less as we know it.

      Staying under that threshold mandates a specific “carbon budget,” an overall amount of carbon dioxide we can add to the atmosphere without pushing warming beyond that temperature. At today’s emissions—about 40 billion to 50 billion tons a year—“there may be only five years’ worth of CO2 emissions left” in the 1.5-degree scenario….

      On a hardened lava field of boulders and moss in the foothills just outside Reykjavlk, Iceland, a machine the size of a one-car garage pulls air through a chemical filter that extracts carbon dioxide. It is powered by waste heat from the geothermal power plant next door, and it pumps the captured carbon dioxide more than 700 meters underground, where the gas reacts with basalt rock and becomes solid mineral. Climeworks, a Swiss start-up, calls the operation the first direct air capture and storage plant in the world. It sequesters a modest 50 tons of carbon dioxide a year.

      Direct air capture and storage may be the most straightforward path to negative emissions: banks of fans would harvest CO2 from the sky and bury it. Scientific scenarios project that this technology could remove 10 billion to 15 billion tons of carbon dioxide a year by the end of the century; a few experts think 35 billion or 40 billion tons may be possible. This is such a tantalizing prospect that many climate scientists worry it could pose a moral hazard: people might think they can delay fossil-fuel reductions now in the hope of technological salvation later….

      Direct air capture also consumes enormous amounts of energy. Removing a million tons of carbon dioxide a year would require a 300- to 500-megawatt power plant….If that were a coal-fired plant, it would create more emis-sions than it would remove. If power came from solar or wind farms, it would cover a lot of land that might already be in demand for farming or nature. And of course, a million tons would barely make a dent in the target of 20 billion tons a year….

On the Safe Side

[These excerpts are from an article by Eric Lindberg in the Winter 2018 issue of the USC Trojan Family.]

      Childhood is a time for wonder and learning, I for exploration and discovery, for making new friends and building confidence. But sometimes that period of innocence is shattered by violence, discrimination or harassment. And that turmoil tends to occur where kids spend most of their day: at school.

      Teachers and administrators deal with bad behavior every day in classrooms across the country.

      Nearly eight in 10 public K-12 schools reported at least one incident of violence, theft or other crime on campus in 2016, according to the National Center for Education Statistics. The latest statewide data show one third of students in California schools are bullied. Rates of suicide and depression among teens have increased substantially in recent decades. And school shootings, although still extremely rare, continue to garner widespread attention.

      So how can we make our schools safer and ensure that students can thrive…?

      There is some cause for optimism, he says, noting that overall crime and violence have decreased both in U.S. society in general and in schools since the mid-1990s, for reasons that remain unclear. Researchers have found that shooting incidents involving students are on the decline, as are virtually all indicators of violence and crime in schools. Nevertheless, many remain fearful.

      A recent survey found that 57 percent of teens say they are worried about a shooting happening at their school. Parents of teens are even more likely to be concerned; 63 percent report being at least somewhat worried about school shootings. Many researchers trace this perception of exaggerated danger in schools to breathless media coverage of high-profile incidents. Mass shootings like the recent tragedy in Parkland, Florida, can have a dramatic effect on feelings of safety….

Toxic Baby Food? Really?

[These excerpts are from an editorial by the editors in the January 2019 issue of Scientific American.]

      Many babies’ first solid food is rice cereal. It is a childhood staple, commonly recommended by pediatricians. And it is often poisoned—at least a little bit. Studies have found that many brands contain measurable amounts of inorganic arsenic, the most toxic kind. It’s not just rice: an August 2018 study by Consumer Reports tested 50 foods made for babies and toddlers, including organic and nonorganic brands such as Gerber, Earth’s Best, Beech-Nut and other popular labels, and found evidence of at least one dangerous heavy metal in every product. Fifteen of the 50 contained enough contaminants to pose potential health risks to a child eating one serving or less a day.

      Heavy metals can impair cognitive development in children, who are especially at risk because of their smaller size and tendency to absorb more of these substances than adults do. Inorganic arsenic in drinking water has been found to lower the IQ scores of children by five to six points. And asheavy metals accumulate in the body over time, they can raise the risk of cancer, reproductive problems, type 2 diabetes, cardiovascular disease and cognitive issues. Of course, finding out your favorite brand is contaminated is not a reason to panic. Low levels of exposure for short periods are unlikely to cause devastating effects, and parents should focus on reducing the overall levels of these toxic substances in their children's total diet to limit harm.

      Heavy metals occur naturally on Earth and are present in soil and water. But pesticides, mining and pollution boost their concentrations, and farming and food manufacturing processes can contribute even more. Some crops inevitably absorb more heavy metals. Rice, for example, readily takes in arsenic both because of its particular physiology and because it is often grown in fields flooded with water, which is a primary source of the metal.

      Cereal makers are clearly capable of keeping baby food poison-free: roughly a third of the products Consumer Reports tested did not contain worrisome metal levels. Companies just do not take enough safety steps….

      Some companies are already trying to investigate the sources of contamination in their products and reduce them. More should follow and be transparent about these efforts. But the best chance of real change from food companies most likely will come with regulation.

      Currently there are no U.S. rules on acceptable levels of heavy metals in baby foods. In 2012, 2015 and 2017 Congress tried and failed to pass legislation imposing limits on arsenic and lead in fruit juice and rice products….

Fast and Furious

[These excerpts are from an article in the Winter 2019 issue of the American Museum of Natural History Rotunda.]

      There’s still a lot we don’t know about the Cretaceous Period’s most famous predator, Tyrannosaurus rex. One thing is for sure: T. rex was a giant. Its size is one of the extinct dinosaur’s most impressive features—along with its bone-crushing bite and disproportionally tiny arms, of course.

      Getting a fuller understanding of T. rex the giant requires scientists to try to learn more about T. rex as a tyke—before it was a mega-predator and, when it was still something else’s prey—as well as its lesser-known, lesser-sized relatives….

      Like many living species, T. rex hatchlings started out a fraction of the size of an adult dinosaur—which could weigh upward of 15,000 pounds, or about the same as five compact cars. But what the small theropods lacked in size, they made up for in speed: scientists think that T. rex gained up to 4.6 pounds a day, or an astonishing 1,690 pounds per year, until its early 20s.

      A ferociously rapid growth rate was one of the things that set T. rex apart from its Mesozoic peers. It matured at an exceptionally quick clip for a dinosaur, leaping way ahead in size of other tyrannosaur species like Albertosaurus and Gorgosourus around age 12. That gave this predator a distinct advantage: by growing out of its young and vulnerable phase quickly, T. rex could spend about 30 percent of its lifetime as one of the largest predators ever to walk the Earth. Compare that to modern crocodilians—close cousins that grow very slowly and, while reaching relatively massive sizes, attain only a fraction of the size and weight of an adult T. rex.

      Paleontologists have derived T. rex’s stunning growth rate by examining a cross-section of fossilized bones for growth lines—markings that are similar to tree rings, and present in nearly all vertebrates. For dinosaurs like T. rex, researchers often sample the thigh bone (femur)….also found success sampling the pelvis, calf bone (fibula), ribs, gastralia, and skull bones. And as with trees, bone growth rings offer a glimpse into an organism’s life history: in T. rex, wide gaps between lines record growth spurts at early ages, and lines that form closer together show a slowdown in growth as the animal approached adulthood….

      Growth rates also allow scientists to peek back at an animal’s early years. Scientists have yet to find a T. rex hatchling fossil. But recent studies based on the growth curve of T. rex suggest that these animals would have been around 2 feet long straight out of the egg, and as juveniles may have weighed as little as 10 pounds….

      Along with growth curves, paleontologists have also looked to other tyrannosaurs—a group that’s bigger, and better studied, today than ever before— for additional clues about how T. rex may have developed and behaved….

      Life expectancy for T. rex improved significantly as it grew, but juvenile fossil specimens are very rare. When a specimen is discovered, paleontologists run up against another problem: how to confirm that a fossil is of a young animal, not of an adult of a smaller, totally new species?

Tropical Uplift May Set Earth’s Thermostat

[These excerpts are from an article by Paul Voosen in the 4 January 2019 issue of Science.]

      Hate the cold? Blame Indonesia. It may sound odd, given the contributions to global warming from the country’s 270 million people, rampant deforestation, and frequent carbon dioxide (CO2)-belching volcanic eruptions. But over much longer times, Indonesia is sucking CO2 out of the atmosphere.

      Many mountains in Indonesia and neighboring Papua New Guinea consist of ancient volcanic rocks from the ocean floor that were caught in a colossal tectonic collision between a chain of island volcanoes and a continent, and thrust high. Lashed by tropical rains, these rocks hungrily react with CO2 and sequester it in minerals. That is why, with only 2% of the world’s land area, Indonesia accounts for 10% of its long-term CO2 absorption. Its mountains could explain why ice sheets have persisted, waxing and waning, for several million years (although they are now threatened by global warming).

      Now, researchers have extended that theory, finding that such tropical mountain-building collisions coincide with nearly all of the half-dozen or so significant glacial periods in the past 500 million years….

      Most geologists agree that long-term changes in the planet’s temperature are governed by shifts in CO2, and that plate tectonics somehow drives those shifts as it remakes the planet's surface. But for several decades, researchers have debated exactly what turns the CO2 knob. Many have focused on the volcanoes that rise where plates dive beneath one another. By spewing carbon from Earth’s interior, they could turn up the thermostat. Others have emphasized rock weathering, which depends on mountain building driven by plate tectonics. When the mountains contain seafloor rocks rich in calcium and magnesium, they react with CO2 dissolved in rainwater to form limestone, which is eventually buried on the ocean floor. Both processes matter….

      Having the right rocks to drive the CO2-chewing reaction is not sufficient. Climate matters, too. For example, the Siberian Traps, a region that saw devastating volcanic eruptions 252 million years ago, are rich in such rocks but absorb little….

Do Plants Favor Their Kin?

[These excerpts are from an article by Elizabeth Pennisi in the 4 January 2019 issue of Science.]

      For people, and many other animals, family matters. Consider how many jobs go to relatives. Or how an ant will ruthlessly attack intruder ants but rescue injured, closely related nestmates. There are good evolutionary reasons to aid relatives, after all. Now; it seems, family feelings may stir in plants as well.

      A Canadian biologist planted the seed of the idea more than a decade ago, but many plant biologists regarded it as heretical—plants lack the nervous systems that enable animals to recognize kin, so how can they know their relatives? But with a series of recent findings, the notion that plants really do care for their most genetically close peers—in a quiet, plant-y way—is taking root. Some species constrain how far their roots spread, others change how many flowers they produce, and a few tilt or shift their leaves to minimize shading of neighboring plants, favoring related individuals….

      Beyond broadening views of plant behavior, the new work may have a practical side. In September 2018, a team in China reported that rice planted with kin grows better, a finding that suggested family ties can be exploited to improve crop yields….

      …She grew American searocket (Calcile edentula), a succulent found on North American beaches, in pots with relatives or with unrelated plants from the same population. With strangers, the searocket greatly expanded its underground root system, but with relatives, it held these competitive urges in check, presumably leaving more room for kin roots get nutrients and water. The claim, published in 2007, shocked colleagues. A few sharply criticized the work, citing flawed st-tistics and bad study design.

      Since then, however, other researchers have confirmed her findings….After growing 770 seedlings in pots either alone or with three or six neighbors of varying relatedness, the team found the plants grown with kin put out more flowers, making them more alluring to pollinators. The floral displays were especially big in plants in the most crowded pots of relatives….

      Doubts linger. Is a plant identifying genetic kin, or simply recognizing that its neighbor is more or less similar to itself…?

      Sagebrush bushes (Artemisia tridentate) have provided some strong clues, however. When injured by herbivores, these plants release volatile chemicals that stimulate neighboring sagebrush to make chemicals toxic to their shared enemies….

      Since then, he has shown that when sunflower kin are planted close together, they, too, arrange themselves to stay out of one another's way. The sunflowers incline their shoots alternately toward one side of the row or the other….Taking advantage of the effect, they planted 10 to 14 related plants per square meter—an unheard of density for commercial growers—and got up to 47% more oil from plants that were allowed to lean away from each other than plants forced to grow straight up.

Small Steps, Big Changes

[These excerpts are from an article by Joshua P. Starr in the December 2018/January 2019 issue of Phi Delta Kappan.]

      If we want to make significant improvements in public education, then our goal shouldn't be to find a few more superstars. We know that in every profession people tend to be distributed along a bell curve, with the largest group performing somewhere in the middle. That certainly applies to the 3.7 million teachers working in our public schools. So the way to make the biggest difference is to help the largest group of teachers, those in the middle of the pack, to make regular, ongoing progress, so that the whole bell curve shifts. If we were to bump up the average level of teaching performance across the country over a number of years, that would translate to historic gains in student learning.

      But if our goal is to promote steady progress on a large scale, what does that mean for educational leadership? How do we organize and lead school systems to help our average-performing teachers and staff to get better at their work? I believe, and decades of research findings suggest, that it starts with defining a clear vision for what students need to know and be able to do, and every part of the school system must then be aligned with that goal.

      Again, I know this isn’t the most exciting sales pitch, but it’s much more effective for school and district leaders to implement a number of deliberate and modest, well-aligned changes thoughtfully than to throw themselves (and their professional ambitions) into one or two big, splashy, high-profile initiatives. Creating this sort of systemwide alignment requires us to take a careful look at every part of the system — policy, curriculum, teacher development, assessment, accountability, resource allocation, staffing, community engagement, and school culture — and try to find realistic ways for each to make a stronger contribution to our shared goals. Everything matters, and small steps add up….

      …Whether they focus on curriculum, grading, student assignment, equity, or another topic, policy discussions give teachers and administrators the opportunity to clarify what they want their students to learn and what kinds of support those students will require….

      …Teachers often and rightly complain that one-size-fits-all district-mandated training is meaningless. Yet, educators shouldn’t be left to their own devices either, as professional learning must be aligned with the priorities of the school and system, as well as the developmental needs of both teacher and students.

The Happy (and not so Happy) Accidents of Bush-Obama School Reform

[These excerpts are from an article by Frederick M. Hess and Michael Q. McShane in the December 2018/January 2019 issue of Phi Delta Kappan.]

      The American educational system is sprawling, diverse, and complex. It sits within a political system that itself is sprawling, diverse, and complex. In turn, that system sits within an American culture that is also sprawling, diverse, and complex. These are not design flaws. They represent —for good and bad — the true face of American democracy after more than two centuries of evolution.

      But if our educational system resembles a riddle wrapped in an enigma inside of a mystery, then it must be extraordinarily difficult to predict how reforms will unspool. Thus, reformers should be open to serendipity and Lvalue its gifts….

      No matter how pure our motives or brilliant our theory of action, we do well to recognize that school reforms rarely work as intended, and they sometimes only serve to make matters worse. That’s especially true then it comes to policy implementation. More often than not, students, teachers, and administrators react and behave in unexpected ways, or political forces and real-world dynamics interfere with our carefully designed plans.

      In the case of test-based teacher evaluation and the Common Core, advocates dug in their heels and kept insisting that their ambitious plans made sense — even as those reforms began to face practical challenges and backlash. Further, because policy makers attached timelines to these initiatives, state leaders felt compelled to charge forward, whatever the obstacles, and they were loath to make course corrections for fear of missing benchmarks or breaking promises.

      Thus, instead of taking parents and educators’ concerns seriously and admitting things weren’t playing out as they’d hoped, proponents tended to dismiss their critics as ideological, unreasoning, and “anti-child,” which only made it tougher to find common ground or defuse concerns. Over time, they became more and more preoccupied with tweaking their messages and securing short-term political wins, rather than addressing significant problems or trying to understand the growing opposition to their policies.

      When advocates build a head of steam behind a particular school reform, they may be reluctant to slow down, acknowledge concerns, and address obvious problems. But if they can bring themselves to hit the brakes when necessary; rather than trying to plow through every obstacle, Lthen they’ll be much better equipped for the long haul….

      For all the uncertainties of education policy, some truisms do hold, no matter how inconvenient we may find them: Incentivizing certain behaviors will tend to cause more of that behavior; people will go to great lengths to keep their jobs; if people distrust those who make the rules, they will push back on those rules; and if reformers neglect to anticipate and account for these things, they will likely encounter more unhappy accidents than happy ones.

How Cognitive Psychology Informs Classroom Practice

[These excerpts are from an article by Pooja K. Agarwal and Henry L. Roediger III in the December 2018/January 2019 issue of Phi Delta Kappan.]

      1. Retrieval practice boosts learning by pulling information out of students’ heads (by responding to a brief writing prompt, for example), rather than cramming information into their heads (by lecturing at students, for example). In the classroom, retrieval practice can take many forms, including a quick no-stakes quiz. When students are asked to retrieve new information, they don't just show what they know, they solidify and expand it.

      2. Feedback boosts learning by revealing to students what they know and what they don’t know. At the same time, this increases students' metacognition — their understanding about their own learning progress.

      3. Spaced practice boosts learning by spreading lessons and retrieval opportunities out over time so that new knowledge and skills are not crammed in all at once. By returning to content every so often, students’ knowledge has time to be consolidated and then refreshed.

      4. Interleaving — or practicing a mix of skills (such as doing addition, subtraction, multiplication, and division problems all in one sitting) — boosts learning by encouraging connections between and discrimination among closely related topics. Interleaving sometimes slows students’ initial learning of a concept, but it leads to greater retention and learning over time….

      Many teachers already implement these strategies in one form or another. But they may be able to get much more powerful results with a few small tweaks. For example, we often observe teachers using think-pair-share activities in their classrooms — typically, they will give students a few minutes on their own to think about a topic or prompt, then a few more minutes to discuss it with a partner, and then a chance to share their ideas as part of a larger class discussion. But what, exactly, are students doing during the think stage? They could easily be daydreaming, or wondering what to eat for lunch, rather than actively considering the prompt. But if the teacher simply asks them to write down a quick response, rather than just think, it becomes an opportunity for retrieval practice, ensuring that students are drawing an idea out of their heads and onto the paper.

      Similarly, rather than assigning students to consider a new topic, the teacher might ask them to do a think-pair-share about content they learned the day or week before — and now it becomes an opportunity for spaced practice; students get to return to material and solidify their under-standing of it.

      Here’s another example: We often observe teachers begin their classes by saying something to the effect of, “Here’s what we did yesterday ...” and then reviewing the content. Instead, they can pose it as a question, “What did we do yesterday?” and give students a minute to write down what they remember. It's a subtle shift (from a lecture by the teacher to an opportunity for retrieval practice), but it can significantly improve student learning, without requiring additional preparation or classroom time. Even a single question, writing prompt, or quick no-stakes quiz can make a difference, encouraging students to pull information out of their heads rather than cramming it into them via lecturing or telling.

      Why do these strategies improve learning? Consider this quick question: Who was the fourth president of the United States? A plausible answer may have jumped instantly to mind, but you probably had to struggle mentally to come up with a response. It’s precisely this productive struggle or “desirable difficulty” during retrieval practice and the three additional strategies that improves learning. (By the way, the fourth president was James Madison, but you’ll likely remember that much better if you managed to retrieve it from your memory rather than waiting for us to remind you of the name!)

      Teachers can use these four strategies (retrieval practice, feedback-driven metacognition, spaced practice, and interleaving) with confidence because they are strongly backed by research both in laboratories and classrooms. The rigor of science gives us confidence that these strategies aren’t fads, and successful classroom implementation gives us confidence that they work in the real world, not just in the laboratory.

Spin Control

[These excerpts are from an article by Jennifer Chu in the January-February 2019 issue of MIT News.]

      The Beaufort Gyre is an enormous, 600-mile-wide pool of swirling cold, fresh water in the Arctic Ocean, just north of Alaska and Canada. In the winter, this current is covered by a thick cap of ice. Each summer, as the ice melts away, the exposed gyre gathers up sea ice and river runoff, and draws it down to create a huge reservoir of frigid fresh water equal to the volume of all the Great Lakes combined.

      Scientists at MIT have now identified a key mechanism, which they call the “ice-ocean governor,” that controls how fast the Beaufort Gyre spins and how much fresh water it stores. In a recent paper in Geophysical Research Letters, the researchers report that the Arctic's ice cover essentially sets a speed limit on the gyre’s spin.

      In the past two decades, as surface air temperatures have risen, the Arctic’s summer ice has progressively shrunk. The team has observed that with less ice available to control the Beaufort Gyre’s spin, the current has sped up in recent years, gathering up more sea ice and expanding in both volume and depth

      If Arctic temperatures continue to climb, the researchers predict, the mechanism governing the gyre's spin will diminish. With no governor to limit its speed, the gyre is likely to transition into “a new regime” and eventually spill over like an overflowing bathtub, releasing huge volumes of cold, fresh water into the North Atlantic. That could affect the global climate and ocean circulation….

      As Arctic temperatures have risen inl the last two decades, summertime ice has shrunk with each year, the speed of the Beaufort Gyre has increased, and its currents have become more variable and unpredictable, and they are only slightly slowed by the return of ice in the winter.

      An increasingly unstable Beaufort Gyre could also disrupt the Arctic's halocline—the underlying layer of ocean water that insulates ice at the surface from much deeper, warmer, and saltier water. If the halocline is weakened by a more unstable gyre, this could encourage warmer waters to rise up, further melting the Arctic ice….

The Science of Slime

[These excerpts are from an article by Katharina Ribbeck in the January-February 2019 issue of MIT News.]

      Snot. Boogers. Phlegm. The goo that drips from your nose when you have a cold. No matter what you call it, mucus has a bad reputation as an unpleasant waste product, a sign of disease.

      But despite its high ick factor, the slimny substance performs a remarkable range of vital functions. After all, it lines more than 200 square meters of our bodies—from our mouths to the digestive system, urinary tract, lungs, eyes, and cervix. It lubricates and hydrates, lets us swallow, determines what we taste and smell, and selectively filters nutrients, toxins, and living cells such as bacteria, sperm cells, and fungi….

      …mucus is very successful at “taming” normally pathogenic microbes. Until recently, scientists thought this was because it acted as a mechanical barrier, trapping bacteria and other pathogens….

      The primary building blocks of mucus are mucins—long, bottlebrush-like proteins with many sugar molecules called glycans attached. And mucins…actually disrupt many key functions of infectious bacteria….

      With those powers cut off, bacteria can no longer colonize on a surface to form persistent slimy layers called biofilms, which tend to be more harmful than the cells are individually: they can cause a wide range of health problems, including dental cavities and ulcers, and can prove fatal for people with cystic fibrosis….

      More than 10% of babies born worldwide arrive before full term, defined as 37 weeks of gestation, but there had been no reliable way to predict preterm labor….the mucus from women at high risk of early labor is mechanically weaker, more elastic, more permeable, and less adhesive. Preterm birth may occur because the cervical mucus is more susceptible to invasion by microbes that can cause infection.

      Other conditions that alter mucus include digestive diseases such as Crohn’s and ulcerative colitis, as well as respiratory diseases….

Artificial Intelligence and Ethics

[This excerpt is from an article by Jonathan Shaw in the January-February 2019 issue of Harvard Magazine.]

      “Artificial intelligence” refers to systems that can be designed to take cues from their environment and, based on those inputs, proceed to solve problems, assess risks, make predictions, and take actions. In the era predating powerful computers and big data, such systems were programmed by humans and followed rules of human invention, but advances in technology have led to the development of new approaches. One of these is machine learning, now the most active area of AI, in which statistical methods allow a system to “learn” from data, and make decisions, without being explicitly programmed. Such systems pair an algorithm, or series of steps for solving a problem, with a knowledge base or stream—the information that the algorithm uses to construct a model of the world.

      Ethical concerns about these advances focus at one extreme on the use of AI in deadly military drones, or on the risk that Al could take down global financial systems. Closer to home, Al has spurred anxiety about unemployment, as autonomous systems threaten to replace millions of truck drivers, and make Lyft and Uber obsolete. And beyond these larger social and economic considerations, data scientists have real concerns about bias, about ethical implementations of the technology, and about the nature of interactions be-tween AI systems and humans if these systems are to be deployed properly and fairly in even-the most mundane applications.

      Consider a prosaic-seeming social change: machines are already being given the power to make life-altering, everyday decisions about people. Artificial intelligence can aggregate and assess vast quantities of data that are sometimes beyond human capacity to analyze unaided, thereby enabling AI to make hiring recommendations, determine in seconds the creditworthiness of loan applicants, and predict the chances that criminals will re-offend.

      But such applications raise troubling ethical issues because AI systems can reinforce what they have learned from real-world data, even amplifying familiar risks, such as racial or gender bias. Systems can also make errors of judgment when confronted with unfamiliar scenarios. And because many such systems are “black boxes,” the reasons for their decisions are not easily accessed or understood by humans—and therefore difficult to question, or probe.

      Examples abound. In 2014, Amazon developed a recruiting tool for identifying software engineers it might want to hire; the system swiftly began discriminating against women, and the company abandoned it in 2017. In 2016, ProPublica analyzed a commercially developed system that predicts the likelihood that criminals will re-offend, created to help judges make better sentencing decisions, and found that it was biased against blacks. During the past two years, self-driving cars that rely on rules and training data to operate have caused fatal accidents when confronted with unfamiliar sensory feedback or inputs their guidance systems couldn’t interpret. The fact that private commercial developers generally refuse to make their code available for scrutiny, because the software is considered proprietary intellectual property, is another form of non-transparency—legal, rather than technical.

      Meanwhile, nothing about advances in the technology, per se, will solve the underlying, fundamental problem at the heart of AI, which is that even a thoughtfully designed algorithm must make decisions based on inputs from a flawed, imperfect, unpredictable, idiosyncratic real world.

Needle in the Haystack

[These excerpts are from an article by Thomas Hingham and Katrina Douka in the December 2018 issue of Scientific American.]

      Denisova Cave is at the center of a revolution in scientists’ understanding of how our ancestors in the Paleolithic, or Old Stone Age, behaved and interacted. Our species, Homo sapiens, originated in Africa hundreds of thousands of years ago. When it eventually began spreading into Europe and Asia, it encountered other human species, such as the Neandertals, and shared the planet with them for millennia before those archaic species disappeared. Scientists know these groups encountered one another because people today carry DNA from our extinct relatives—the result of interbreeding between early H. sapiens and members of those other groups. What we do not yet know and are eager to ascertain is when and where they crossed paths, how often they interbred and how they might have influenced one another culturally. We actually have quite a few important archaeological sites from this transitional period that contain stone tools and other artifacts. But many of these sites, including Denisova, lack human fossils that are complete enough to attribute to a particular species on the basis of their physical traits. That absence has hindered our ability to establish which species made what—and when.

      Now a technique for identifying ancient bone fragments, known as zooarchaeology by mass spectrometry (ZooMS), is finally allowing researchers to start answering these long-standing questions. By analyzing collagen protein preserved in these seemingly uninformative fossil scraps, we can identify the ones that come from the human/great ape family and then attempt to recover DNA from those specimens. Doing so can reveal the species they belong to—be it Neandertal, H. sapiens or something else. What is more, we can carry out tests to determine the ages of the fragments.

      Directly dating fossils is a destructive process—one has to sacrifice some of the bone for analysis. Museum curators are thus usually loath to subject more complete bones to these tests. But they have no such reservations with the scraps.

      The ability to directly date fossils found in association with artifacts is especially exciting with regard to Denisova and other sites we know sheltered multiple human species in the past. A number of researchers have argued that symbolic and decorative artifacts, which are proxies for modern cognitive abilities, are unique to H. sapiens. Others maintain that Neandertals and other species made such items, too, and may have even passed some of their traditions along to the H. sapiens they met. The ability to identify and date these fossil fragments means researchers can begin to reconstruct the chronology of these sites in far greater detail and elucidate a critical chapter of human prehistory….

      ZooMS, also called collagen peptide mass fingerprinting, allows investigators to assign fragments of bone to the proper taxonomic group by analyzing the proteins in bones. Bone collagen protein is made up of hundreds of small compounds called peptides that vary slightly among different types of animals. By comparing the peptide signatures of mystery bones against a library of such signatures from known animals, it is possible to assign the unidentified bones to the correct family, genus and sometimes species….

Meat Grown from Stem Cells

[These excerpts are from an article by G. Owen Schaefer in the December 2018 issue of Scientific American.]

      Imagine biting into a juicy beef burger that was produced without killing animals. Meat grown in a labora-tory from cultured cells is turning that vision into a reality. Several start-ups are developing lab-grown beef, pork, poultry and seafood….

      If widely adopted, lab-grown meat, also called clean meat, could eliminate much of the cruel, unethical treatment of animals that are raised for food. It could also reduce the considerable environmental costs of meat production; resources would be needed only to generate and sustain cultured cells, not an entire organism from birth.

      The meat is made by first taking a muscle sample from an animal. Technicians collect stem cells from the tissue, multiply them dramatically and allow them to differentiate into primitive fibers that then bulk up to form muscle tissue. Mesa Meat says that one tissue sample from a cow can yield enough muscle tissue to make 80,000 quarter-pounders.

      A number of the start-ups say they expect to have products for sale within the next fewyears. But clean meat will have to overcome a number of barriers if it is to be commer-cially viable.

      Two are cost and taste. In 2013, when a burger made from lab-grown meat was presented to journalists, the patty cost more than $300,000 to produce and was overly dry (from too little fat). Expenses have since fallen. Memphis Meats reported this year that a quarter-pound of its ground beef costs about $600. Given this trend, clean meat could become competitive with traditional meat within several years. Careful attention to texture and judicious supplementing with other ingredients could address taste concerns.

      To receive market approval, clean meat will have to be proved safe to eat. Although there is no reason to think that lab-produced meat would pose a health hazard, the FDA is only now beginning to consider how it should be regulated. Meanwhile traditional meat producers are pushing back, arguing that the lab-generated products are not meat at all and should not be labeled as such, and surveys show that the public has only tepid interest in eating meat from labs. Despite these challenges, the clean meat companies are forging ahead. If they can succeed in creating authentic-tasting products that are also affordable, clean meat could make our daily eating habits more ethical and environmentally sustainable.

Mimicking Spider Silk

[This excerpt is from an article by Prachi Patel in the December 2018 issue of Scientific American.]

      Spiders spin the stuff of engineers’ dreams. Their silk is as strong as steel, stretchy, nontoxic and biodegradable. But spiders are not easy to farm. Each produces only a minuscule amount of silk, and some are cannibalistic. For decades scientists have tried to mimic the silvery strands to use for sutures, athletic gear and bulletproof vests, but their synthetic fibers have fallen short. Now a team has coaxed bacteria to produce silk as tough and elastic as the natural version.

      Researchers have previously transplanted silk-making DNA from spiders into bacteria, silkworms, plants and even goats in an effort to mass-produce the substance. Until now, however, the best engineered fibers have been only half as strong as the real thing. The secret to spider silk’s strength lies in large protein molecules composed of hundreds of strings of repeated amino acids encoded by similarly lengthy, repetitive DNA sequences….

Fossils Push Back Origin of Key Plant Groups Millions of Years

[These excerpts are from an article by Elizabeth Pennisi in the 21 December 2018 issue of Science.]

      Paleobotanists exploring a site near the Dead Sea have unearthed a startling connection between today’s conifer forests in the Southern Hemisphere and an unimaginably distant time torn apart by a global cataclysm. Exquisitely preserved plant fossils show the podocarps, a group of ancient evergreens that includes the massive yellowwood of South Africa and the red pine of New Zealand, thrived in the Permian period, more than 250 million years ago. That's tens of millions of years earlier than thought, and it shows that early podocarps survived the “great dying” at the end of the Permian, the worst mass extinction the planet has ever known.

      …the fossils push back the origins not just of podocarps, but also of groups of seed ferns and cycadlike plants. Beyond altering notions of plant evolution, the discoveries lend support to a 45-year-old idea that the tropics serve as a “cradle” of evolution….

      During the Permian, from 299 million to 251 million years ago, Earth's landmasses had merged to form a supercontinent, bringing a cooler, drier climate. Synapsids, thought to be ancient predecessors of mammals, and saumpsids, ancestors to reptiles and birds, roamed the landscape. Simple seed-bearing plants had already appeared on the scene. Family trees reconstructed from the genomes of living plants suggest more sophisticated plant groups might also have evolved during the Permian, but finding well-preserved plant fossils from that time has been difficult.

      …Many of the fossils preserve the ancient plants' cuticle, a waxy surface layer that captures fine features, such as the leaf pores called stomata. That made it possible for the team to positively identify many of the plants….

      Such finds could help resolve an ongoing debate about why the tropics have more species than colder latitudes do. Some have suggested that species originate at many latitudes but are more likely to diversify in the tropics, with its longer growing seasons, higher rainfall and temperatures, and other features. But another theory proposes that most plant—and animal—species actually got their start near the equator, making the low latitudes an evolutionary “cradle” from which some species migrate north and south….

      It’s not clear how the newfound Permian plants made it through the great dying, a 100,000-year period when, for reasons that are still unclear, 90% of marine life and 70% of life on land disappeared. But their presence in the Permian raises the possibility that other plant groups thought to have later origins actually emerged then in the tropics….

Antarctic Ice Melt 125,000 Years Ago Offers Warning

[These excerpts are from an article by Paul Voosen in the 21 December 2018 issue of Science.]

      Some 125,000 years ago, during the last brief warm period between ice ages, Earth was awash. Temperatures during this time, called the Eemian, were barely higher than in today’s greenhouse-warmed world. Yet proxy records show sea levels were 6 to 9 meters higher than they are today, drowning huge swaths of what is now dry land.

      Scientists have now identified the source of all that water: a collapse of the West Antarctic Ice Sheet. Glaciologists worry about the present-day stability of this formidable ice mass. Its base lies below sea level, at risk of being undermined by warming ocean waters, and glaciers fringing it are retreating fast. The discovery, teased out of a sediment core and reported last week at a meeting of the American Geophysical Union in Washington, D.C., validates those concerns, providing evidence that the ice sheet disappeared in the recent geological past under climate conditions similar to today’s….

      …Once the ancient ice sheet collapse got going, some records suggest, ocean waters rose as fast as some 2.5 meters per century.

      …Global temperatures were some 2°C above preindustrial levels (compared with 1°C today). But the cause of the warming was not greenhouse gases, but slight changes in Earth's orbit and spin axis, and Antarctica was probably cooler than today. What drove the sea level rise, recorded by fossil corals now marooned well above high tide, has been a mystery.

Choices in the Climate Commons

[These excerpts are from an editorial by Scott Barrett in the 14 December 2018 issue of Science.]

      Climate change is a tragedy of the commons of existential importance….American ecologist Garrett Hardin’s classic article, “The Tragedy of the Commons,” published in Science 50 years ago this week, vividly describes the dilemma that causes this behavior….

      …Hardin’s proposed corrective is “mutual coercion.” Writing in 1651, British philosopher Thomas Hobbes similarly concluded that a sovereign is needed to tie people “by fear of punishment to the performance of their covenants.”

      However, a critical difference between climate change and Hardin’s parable is that the players in the climate game are nation states. Although individuals can be subjected to coercion by a higher authority, human organization has not evolved to give any institution sovereignty over the nation state. Solutions to global collective action problems must involve covenants (treaties) among states that are self-enforcing.

      To stabilize the climate, a treaty must get all states to (i) participate in and (ii) comply with an agreement that (iii) drives emissions to zero. The Paris Agreement, adopted at the 2015 summit, secures the first requirement, and possibly the second, but only because it is a voluntary agreement and will fall short of meeting the third requirement. The Montreal Protocol, negotiated in 1987 to protect the stratospheric ozone layer, meets all three requirements, thanks partially to a ban on trade in chlorofluorocarbons between parties to the protocol and nonparties. Because of the ban, once the vast majority of countries joined the agreement, all others wanted to join. William Nordhaus, a recipient of this year’s Nobel Memorial Prize in Economic Sciences, has recently analyzed a similar cure for climate change in which members of a “climate club” who agree to curb emissions impose a tariff on imports from nonmembers to encourage their participation. Unfortunately, his analysis shows that as the carbon tax rises to the level needed to stabilize the climate, participation in the club collapses.

      Breaking up the problem may provide more leverage for enforcement. The Kigali Amendment to the Montreal Protocol, adopted in December 2016, phases down hydrofluorocarbons, a group of greenhouse gases, and this will be effective in addressing this particular cause of climate change for the same reasons that the Montreal Protocol has been effective in protecting the ozone layer. Other climate agreements, adopted in parallel with the Paris Agreement, should be negotiated for individual sectors, such as aluminum and steel and international aviation and shipping, all linked to trade.

      However, the time has come to contemplate other, more radical solutions. The October 2018 Intergovernmental Panel on Climate Change special report concluded that limiting temperature change to 1.5°C cannot be achieved by simply curbing emissions, but requires removing CO2 from the atmosphere. The only true “backstop” for limiting climate change is removal of CO2 by industrial processes, which converts the problem from one of changing behavior into one of joint financing of a large-scale project. Another option, solar geoengineering, acts directly on global mean temperature, but is considered risky. Of course, not using it could also be risky. In the end, regardless of pathways forward, we will have to choose between risks to address the scale of this problem and achieve, rather than merely aspire to, global collective action on climate change.

Ireland Slashes Peat Power to Lower Emissions

[These excerpts are from an article by Emily Toner in the 14 December 2018 issue of Science.]

      In Ireland, peat has been used for centuries to warm homes and fire whiskey distilleries. For a country with little coal, oil, and gas, peat—deep layers of partially decayed moss and other plant matter—is also a ready fuel for power plants. Peat power peaked in the 1960s, providing 40% of Ireland’s electricity. But peat is particularly polluting. Burning it for electricity emits more carbon dioxide than coal, and nearly twice as much as natural gas. In 2016, peat generated nearly 8% of Ireland’s electricity, but was responsible for 20% of that sector’s carbon emissions….

      …Bord na Mona, which supplies peat to the three remaining power stations burning it for electricity, announced in October that it would cut its peat supply for electricity by a third by 2020 and end it completely by 2027. Ireland will need to find alternative, lower carbon sources of electricity And approximately 60 bogs no longer needed for fuel will be converted back to wetlands or put to commercial uses such as land for wind farms.

      Behind the phaseout is Ireland's promise to the European Union to reduce greenhouse gas emissions by 20% in 2020, compared with 2005 levels….Despite rapid growth in wind power and increasingly energy efficient homes and vehicles, it will struggle to reduce emissions by even 1%...

      And replacing peat with biomass, as the power companies plan to do, is not a panacea. A decade ago, Bord na Mona began to cofuel a peat-burning station with mixtures of biomass including a grass called miscanthus, olive pits, almond shells, palm kernel shells, and beet pulp, much of it imported from all over the world. Because biomass takes up carbon from the atmosphere as it grows, the European Union counts it as a carbon-neutral, renewable resource—even though transportation, processing, and land-use costs make it less so….

      Rehabilitating the harvested peatlands, however, is a clear plus for climate. When bogs are drained to harvest peat, or for any other use, such as agriculture, grazing, or forestry, exposure to oxygen jump-starts the decomposition of the stored organic matter, releasing carbon into the atmosphere….

      …As a result, say ecologists, conserving peatlands has a triple benefit: reducing emissions from both power plants and exposed fields and, with restored plant life, sequestering more carbon in future peat deposits….

      Moreover, healthy peatlands improve water quality and provide needed habitat for threatened species such as curlews and marsh fritillary butterflies….

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