The Uninhabitable Earth

by David Wallace-Wells;

  In recent years, researchers have uncovered a whole secret history of adversity woven into the experience of the last half century by the hand of leaded gasoline and lead paint, which seem to have dramatically increased rates of intellectual disability and criminality, and dramatically decreased educational attainment and lifetime earnings, wherever they were introduced. The effects of air pollution seem starker already. Small-particulate pollution, for instance, lowers cognitive performance over time so much that researchers call the effect “huge”: reducing Chinese pollution to the EPA standard, for instance, would improve the country’s verbal test scores by 13 percent and its math scores by 8 percent. (Simple temperature rise has a robust and negative impact on test taking, too: scores go down when it’s hotter out.) Pollution has been linked with increased mental illness in children and the likelihood of dementia in adults. A higher pollution level in the year a baby is born has been shown to reduce earnings and labor force participation at age thirty, and the relationship of pollution to premature births and low birth weight of babies is so strong that the simple introduction of E-ZPass in American cities reduced both problems, in the vicinity of toll plazas, by 10.8 percent and 11.8 percent, respectively, just by cutting down on the exhaust expelled when cars slowed to pay the toll.

  Then there is the more familiar health threat from pollution. In 2013, melting Arctic ice remodeled Asian weather patterns, depriving industrial China of the natural wind-ventilation patterns it had come to depend on, and, as a result, blanketing much of the country’s north in an unbreathable smog. An obtuse-seeming metric called the Air Quality Index categorizes the risks according to an idiosyncratic unit scale tabulating the presence of a variety of pollutants: the warnings begin at 51–100, and at 201–300 include promises of “significant increase in respiratory effects in the general population.” The index tops out with the 301–500 range, warning of “serious aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary disease and the elderly” and “serious risk of respiratory effects in the general population”; at that level, “everyone should avoid all outdoor exertion.” The Chinese “airpocalypse” of 2013 doubled the high end of that upper range, reaching a peak Air Quality Index of 993, and scientists studying the phenomenon suggested that China had inadvertently invented an entirely new and unstudied kind of smog, one that combined the “pea soup” pollution of industrial-era Europe and the small-particulate pollution that has lately contaminated so much of the developing world. That year, smog was responsible for 1.37 million deaths in the country.

  Outside of China, most saw the photographs and video of a world capital blanketed by gray so thick it blotted out the sun as a sign, not of the state of the planet’s atmosphere, but of just how backward that one country was—just how far China lagged behind the quality-of-life indices of the first world, whatever its rapid economic growth suggested about its place in the global pecking order. Then, in the record California wildfire season of 2017, the air around San Francisco was worse than on the same day in Beijing. In Napa, the Air Quality Index hit 486. In Los Angeles, there was a run on surgical masks; in Santa Barbara, residents scooped ash from their drainpipes by the handful. In Seattle, the following year, wildfire smoke made it unsafe for anyone, anywhere, to breathe outside. Which gave Americans one more reason—panic about their own health—to look away from the situation in Delhi, where in 2017 the Air Quality Index reached 999.

  The Indian capital is home to 26 million people. In 2017, simply breathing its air was the equivalent of smoking more than two packs of cigarettes a day, and local hospitals saw a patient surge of 20 percent. Runners in Delhi’s half marathon competed with their heads wrapped by white masks. And air that thick with smut is hazardous in other ways: visibility was so low that cars crashed in pileups on Delhi’s highways, and United canceled flights in and out of the city.

  New research shows that even short-term exposure to particulate pollution can dramatically increase rates of respiratory infections, with every additional ten micrograms per cubic meter associated with a rise in diagnoses between 15 and 32 percent. Blood pressure goes up, too. In 2017, The Lancet reported, nine million premature deaths globally were from small-particulate pollution; more than a quarter were in India. And that was before final figures were in from that year’s spike.

  In Delhi, much of the pollution comes from the burning of nearby farmland; but elsewhere small-particulate smog is produced primarily by diesel and gas exhaust and other industrial activity. The public health damage is indiscriminate, touching nearly every human vulnerability: pollution increases prevalence of stroke, heart disease, cancer of all kinds, acute and chronic respiratory diseases like asthma, and adverse pregnancy outcomes, including premature birth. New research into the behavioral and developmental effects is perhaps even scarier: air pollution has been linked to worse memory, attention, and vocabulary, and to ADHD and autism spectrum disorders. Pollution has been shown to damage the development of neurons in the brain, and proximity to a coal plant can deform your DNA.

  In the developing world, 98 percent of cities are enveloped by air above the threshold of safety established by the WHO. Get out of urban areas and the problem doesn’t much improve: 95 percent of the world’s population is breathing dangerously polluted air. Since 2013, China has undertaken an unprecedented cleanup of its air, but as of 2015 pollution was still killing more than a million Chinese each year. Globally, one out of six deaths is caused by air pollution.

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  Pollution like this isn’t news in any meaningful sense; you can find omens about the toxicity of smog and the dangers of blackened air, for instance, in the writing of Charles Dickens, rarely appreciated as an environmentalist. But every year we are discovering more and more ways in which our industrial activity is poisoning the planet.

  One particular note of alarm has been struck by what seems like an entirely new—or newly understood—pollution threat: microplastics. Global warming did not bring us microplastics in any direct way, and yet their rapid conquest of our natural world has become an irresistible fable about just what kind of transformation is meant by the word “Anthropocene,” and just how much the world’s booming consumer culture is to blame.

  Environmentalists probably know already about “the Great Pacific garbage patch”—that mass of plastic, twice the size of Texas, floating freely in the Pacific Ocean. It is not actually an island—in fact, it is not actually a stable mass, only rhetorically convenient for us to think of it that way. And it is mostly composed of larger-scale plastics, of the kind visible to the human eye. The microscopic bits—700,000 of them can be released into the surrounding environment by a single washing-machine cycle—are more insidious. And, believe it or not, more pervasive: a quarter of fish sold in Indonesia and California contain plastics, according to one recent study. European eaters of shellfish, one estimate has suggested, consume at least 11,000 bits each year.

  The direct effect on ocean life is even more striking. The total number of marine species said to be adversely affected by plastic pollution has risen from 260 in 1995, when the first assessment was carried out, to 690 in 2015 and 1,450 in 2018. A majority of fish tested in the Great Lakes contained microplastics, as did the guts of 73 percent of fish surveyed in the northwest Atlantic. One U.K. supermarket study found that every 100 grams of mussels were infested with 70 particles of plastic. Some fish have learned to eat plastic, and certain species of krill are now functioning as plastic processing plants, churning microplastics into smaller bits that scientists are now calling “nanoplastics.” But krill can’t grind it all down; in one square mile of water near Toronto, 3.4 million microplastic particles were recently trawled. Of course, seabirds are not immune: one researcher found 225 pieces of plastic in the stomach of a single three-month-old chick, weighing 10 percent of its body mass—the equivalent of an average human carrying about ten to twenty pounds of plastic in
a distended belly. (“Imagine having to take your first flight out to sea with all that in your stomach,” the researcher told the Financial Times, adding: “Around the world, seabirds are declining faster than any other bird group.”)

  Microplastics have been found in beer, honey, and sixteen of seventeen tested brands of commercial sea salt, across eight different countries. The more we test, the more we find; and while nobody yet knows the health impact on humans, in the oceans a plastic microbead is said to be one million times more toxic than the water around it. Chances are, if we started slicing open human cadavers to look for microplastics—as we are beginning to do with tau proteins, the supposed markers of CTE and Alzheimer’s—we’d be finding plastic in our own flesh, too. We can breathe in microplastics, even when indoors, where they’ve been detected suspended in the air, and do already drink them: they are found in the tap water of 94 percent of all tested American cities. And global plastic production is expected to triple by 2050, when there will be more plastic in the ocean than fish.

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  Plastic panic has a strange relationship to climate change, in that it seems to draw on premonitions about the degradation of the planet while focusing on something that has very little to do with global warming. But it’s not only carbon emissions that are tied up in climate change. Other pollution is, too. One of the connections is relatively attenuated: plastics are produced by industrial activity that also produces pollutants, including carbon dioxide. A second is more direct but, in the scheme of things, trivial: when plastics degrade, they release methane and ethylene, another powerful greenhouse gas.

  But a third relationship between non-carbon pollution and the temperature of the planet is far more horrifying. This is not the problem of plastic but of “aerosol pollution”—the blanket term for any particles suspended in our atmosphere. Aerosol particles actually suppress global temperature, mostly by reflecting sunlight back into outer space. In other words, all of the non-carbon pollution we’ve exhausted from our power plants and our factories and our automobiles—suffocating some of the largest and most prosperous cities of the world and consigning many millions of the lucky to hospital beds, and many millions of others to early deaths—all of that pollution has been, perversely, reducing the amount of global warming we are currently experiencing.

  How much? Probably about half a degree—and possibly more. Already, aerosols have been reflecting so much sunlight away from the earth that, in the industrial era, the planet has only heated up two-thirds as much as it would have otherwise. If we had somehow managed to produce precisely the same volume of carbon emissions since the beginning of the Industrial Revolution as we have, while somehow keeping the skies clear of aerosol pollution, the temperature rise would be half again higher than it is now. The result is what the Nobel laureate Paul Crutzen has called a “Catch-22” and what the climate writer Eric Holthaus has described, perhaps more incisively, as a “devil’s bargain”: a choice between public-health-destroying pollution on the one hand, and, on the other, clear skies whose very clearness and healthiness will dramatically accelerate climate change. Eliminate that pollution and you save millions of lives each year, but also create a dramatic spike in warming. That would bring us to between 1.5 and 2 degrees warmer than the preindustrial baseline—pushing us right up to the threshold of 2 degrees of warming, long thought to be the border separating a livable future from climate catastrophe.

  For almost a generation now, engineers and futurists have contemplated the practical implications of this phenomenon, and the prospect of suppressing global temperature with a program of suspended particles—that is, polluting the air on purpose to keep the planet cooler. Often grouped together under the umbrella term “geoengineering,” this prospect has been received by the public as a worst-case scenario, nearly science fiction—and has, in fact, informed much of the recent sci-fi that has addressed itself to the climate crisis. And yet it has gained a terrific amount of currency among the most concerned climate scientists, many of whom will also note that none of the quite modest goals of the Paris climate accords can be achieved without negative-emissions technologies—at present prohibitively expensive.

  Carbon capture may indeed prove to be “magical thinking,” but the cruder technologies—we know these will work. Rather than sucking carbon out of the atmosphere, we could shoot pollution into the sky on purpose; perhaps the most plausible version involves sulfur dioxide. That would turn our sunsets very red, would bleach the sky, would make more acid rain.

  It would also cause tens of thousands of additional premature deaths each year, through its effect on air quality. A 2018 paper suggested it would rapidly dry the Amazon, producing many more wildfires. The negative effect on plant growth would entirely cancel out the positive effect on global temperature, according to another 2018 paper; in other words, at least in terms of agricultural yield, solar geoengineering would offer no net benefit at all.

  Once we began such a program, we could never stop. Even a brief interruption, a temporary dispersal of our red sulfur umbrella, could send the planet plunging several degrees of warming forward into a climate abyss. Which would make whatever installations were sustaining that umbrella quite vulnerable to political gamesmanship and terrorism, as its advocates themselves would acknowledge. And yet many scientists still describe geoengineering as an inevitability—it’s just so cheap, they say. Even an environmentalist billionaire, going rogue, could make it happen on their own.

  Plagues of Warming

  Rock is a record of planetary history, eras as long as millions of years flattened by the forces of geological time into strata with amplitudes of just inches, or just an inch, or even less. Ice works that way, too, as a climate ledger, but it is also frozen history, some of which can be reanimated when unfrozen. There are now, trapped in Arctic ice, diseases that have not circulated in the air for millions of years—in some cases, since before humans were around to encounter them. Which means our immune systems would have no idea how to fight back when those prehistoric plagues emerge from the ice. Already, in laboratories, several microbes have been reanimated: a 32,000-year-old “extremophile” bacteria revived in 2005, an 8-million-year-old bug brought back to life in 2007, a 3.5-million-year-old one a Russian scientist self-injected, out of curiosity, just to see what would happen. (He survived.) In 2018, scientists revived something a bit bigger—a worm that had been frozen in permafrost for the last 42,000 years.

  The Arctic also stores terrifying diseases from more recent times. In Alaska, researchers have discovered remnants of the 1918 flu that infected as many as 500 million, and killed as many as 50 million—about 3 percent of the world’s population, and almost six times as many as had died in the world war for which the pandemic served as a kind of gruesome capstone. Scientists suspect smallpox and the bubonic plague are trapped in Siberian ice, among many other diseases that have otherwise passed into human legend—an abridged history of devastating sickness, left out like egg salad in the Arctic sun.

  Many of these frozen organisms won’t actually survive the thaw; those that have been brought back to life have been reanimated typically under fastidious lab conditions. But in 2016, a boy was killed and twenty others infected by anthrax released when retreating permafrost exposed the frozen carcass of a reindeer killed by the bacteria at least seventy-five years earlier; more than two thousand present-day reindeer died.

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  What concerns epidemiologists more than ancient diseases are existing scourges relocated, rewired, or even re-evolved by warming. The first effect is geographical. Before the early modern period, human provinciality was a guard against pandemic—a bug could wipe out a town, or a kingdom, or even in an extreme case devastate a continent—but in most instances it couldn’t travel much farther than its victims, which is to say, not very far at all. The Black Death killed as much as 60 percent of Europe, but consider, for a gruesom
e counterfactual, how big its impact might have been in a truly globalized world.

  Today, even with globalization and the rapid intermingling of human populations, our ecosystems are mostly stable, and this functions as another limit—we know where certain bugs can spread, and know the environments in which they cannot. (This is why certain vectors of adventure tourism require dozens of new vaccines and prophylactic medications, and why New Yorkers traveling to London don’t need to worry.)

  But global warming will scramble those ecosystems, meaning it will help disease trespass those limits as surely as Cortés did. The footprint of every mosquito-borne illness is presently circumscribed, but those borders are disappearing rapidly, as the tropics expand—the current rate is thirty miles per decade. In Brazil, for generations, yellow fever sat in the Amazon basin, where the Haemagogus and Sabethes mosquitoes thrived, making the disease a concern for those who lived, worked, or traveled deep into the jungle, but only for them; in 2016, it left the Amazon, as more and more mosquitoes fanned out of the rain forest; and by 2017 it had reached areas around the country’s megalopolises, São Paulo and Rio de Janeiro—more than thirty million people, many of them living in shantytowns, facing the arrival of a disease that kills between 3 and 8 percent of those infected.

  Yellow fever is just one of the plagues that will be carried by mosquitoes as they migrate, conquering more and more of a warming world—the globalization of pandemic disease. Malaria alone kills a million people each year already, infecting many more, but you don’t worry much about it if you are living in Maine or France. As the tropics creep northward and mosquitoes migrate with them, you may; over the course of the next century, more and more of the world’s population will be living under the shadow of diseases like these. You didn’t much worry about Zika before a couple of years ago, either.