The Uninhabitable Earth: Life After Warming

by David Wallace-Wells

And there is already, right now, fully a third more carbon in the atmosphere than at any point in the last 800,000 years—perhaps in as long as 15 million years. There were no humans then. The oceans were more than a hundred feet higher.

fact, more than half of the carbon exhaled into the atmosphere by the burning of fossil fuels has been emitted in just the past three decades. Which means we have done as much damage to the fate of the planet and its ability to sustain human life and civilization since Al Gore published his first book on climate than in all the centuries—all the millennia—that came before.

The majority of the burning has come since the premiere of Seinfeld.

Since the end of World War II, the figure is about 85 percent. The story of the industrial world’s kamikaze mission is the story of a single lifetime—the planet brought from seeming stability to the brink of catastrophe in the years between a baptism or bar mitzvah and a funeral.

The Kyoto Protocol achieved, practically, nothing; in the twenty years since, despite all of our climate advocacy and legislation and progress on green energy, we have produced more emissions than in the twenty years before.

The upper end of the probability curve put forward by the U.N. to estimate the end-of-the-century, high emissions scenario—the worst-case outcome of a worst-case path—puts us at eight degrees. Warming of that level would require a suicidal cocktail of sadistic policy, public indifference, and catastrophic luck. But at eight degrees, humans at the equator and in the tropics would not be able to move around without dying; hardly any land on the planet would be capable of efficiently producing any of the food we now eat; forests would be roiled by rolling storms of fire, and coasts would be punished by more and more intense hurricanes; the suffocating hood of tropical disease would reach northward to enclose parts of what we now call the Arctic; probably about a third of the planet would be made unlivable by direct heat; and what are today literally unprecedented and intolerable droughts and heat waves would be the quotidian condition of whatever human life was able to endure.

It is a very strange argument; if the planet is warming at a terrifying pace and on a horrifying scale, it should transparently concern us more, rather than less, that the warming is beyond our control, possibly even our comprehension.

By the end of the century, the World Bank has estimated, the coolest months in tropical South America, Africa, and the Pacific are likely to be warmer than the warmest months at the end of the twentieth century.

As I type that sentence, in the California desert in mid-June, it is 121 degrees outside my door. It is not a record high.

Three-quarters of a century since global warming was first recognized as a problem, we have made no meaningful adjustment to our production or consumption of energy to account for it and protect ourselves.

Globally, coal power has nearly doubled since 2000. According to one analysis, if the world as a whole followed the Chinese example, it would bring five degrees of warming by 2100.

Over the past fifteen years, the iconoclastic mathematician Irakli Loladze has isolated a dramatic effect of carbon dioxide on human nutrition unanticipated by plant physiologists: it can make plants bigger, but those bigger plants are less nutritious. “Every leaf and every grass blade on earth makes more and more sugars as CO2 levels keep rising,” Loladze told Politico, in a story about his work headlined “The Great Nutrient Collapse.” “We are witnessing the greatest injection of carbohydrates into the biosphere in human history—[an] injection that dilutes other nutrients in our food supply.”

Since 1950, much of the good stuff in the plants we grow—protein, calcium, iron, vitamin C, to name just four—has declined by as much as one-third, a landmark 2004 study showed. Everything is becoming more like junk food. Even the protein content of bee pollen has dropped by a third.

What is coming? Much more fire, much more often, burning much more land. Over the last five decades, the wildfire season in the western United States has already grown by two and a half months; of the ten years with the most wildfire activity on record, nine have occurred since 2000.

And it surely doesn’t help that the entire coastline of Louisiana is being swallowed by the sea, with 2,000 square miles already gone. The state loses a football field of land every single hour. In the Florida Keys, 150 miles of road need to be raised to stay ahead of sea level, costing as much as $7 million each mile, or up to $1 billion, total. The county’s 2018 road budget was $25 million.

the amount of ocean water with no oxygen at all has quadrupled globally, giving us a total of more than four hundred “dead zones”; oxygen-deprived zones have grown by several million square kilometers, roughly the size of all of Europe; and hundreds of coastal cities now sit on fetid, under-oxygenated ocean.

In 2014, a not-atypical toxic event struck Lake Erie, when fertilizer from corn and soy farms in Ohio spawned an algae bloom that cut off drinking water for Toledo.

Dramatic declines in ocean oxygen have played a role in many of the planet’s worst mass extinctions, and this process by which dead zones grow—choking off marine life and wiping out fisheries—is already quite advanced not only in the Gulf of Mexico but just off Namibia, where hydrogen sulfide is bubbling out of the sea along a thousand-mile stretch of land known as the Skeleton Coast. The name originally referred to the detritus of wrecked ships, but today it’s more apt than ever. Hydrogen sulfide is also one of the things scientists suspect finally capped the end-Permian extinction, once all the feedback loops had been triggered. It is so toxic that evolution has trained us to recognize the tiniest, safest traces, which is why our noses are so exquisitely skilled at registering flatulence.

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.

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.

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.

The culprit, it turned out, was a simple bacteria, Pasteurella multocida, which had lived inside the saiga’s tonsils, without threatening its host in any way, for many, many generations. Suddenly it had proliferated, emigrated to the bloodstream, and from there to the animals’ liver, kidneys, and spleen. Why? “The places where the saigas died in May 2015 were extremely warm and humid,” Ed Yong wrote in The Atlantic. “In fact, humidity levels were the highest ever seen in the region since records began in 1948. The same pattern held for two earlier, and much smaller, die-offs from 1981 and 1988. When the temperature gets really hot, and the air gets really wet, saiga die. Climate is the trigger, Pasteurella is the bullet.” This is not to say we now understand what precisely about humidity weaponized Pasteurella, or how many of the other bacteria living inside mammals like us—the 1 percent we have identified, or perhaps more worryingly the 99 percent we house without any knowledge or understanding—might be similarly triggered by climate, friendly, symbiotic bugs with whom we’ve lived in some cases for millions of years, transformed suddenly into contagions already inside us. That remains a mystery. But ignorance is no comfort. Presumably climate change will introduce us to some of them.

(Every round-trip plane ticket from New York to London, keep in mind, costs the Arctic three more square meters of ice.)

Plastic panic is another exemplary climate parable, in that it is also a climate red herring. The panic arises from the admirable desire to leave a smaller imprint on the planet, and a natural horror that the environment is so polluted by detritus passing through our air, our food, our flesh—in this way, it draws on a very modern obsession with hygiene and lightness as a form of consumer grace (an obsession familiar from recycling). But while plastics have a carbon footprint, plastic pollution is simply not a global warming problem—and yet it has slid into the center of our vision, at least briefly, the ban on plastic straws occluding, if only for a moment, the much bigger and much broader climate threat.

Ninety-six percent of the world’s mammals, by weight, are now humans and their livestock; just four percent are wild.

Over the last twenty-five years, the cost per unit of renewable energy has fallen so far that you can hardly measure the price, today, using the same scales (since just 2009, for instance, solar energy costs have fallen more than 80 percent). Over the same twenty-five years, the proportion of global energy use derived from renewables has not grown an inch. Solar isn’t eating away at fossil fuel use, in other words, even slowly; it’s just buttressing it. To the market, this is growth; to human civilization, it is almost suicide. We are now burning 80 percent more coal than we were just in the year 2000.

The cryptocurrency now produces as much CO2 each year as a million transatlantic flights.

If we had started global decarbonization in 2000, when Al Gore narrowly lost election to the American presidency, we would have had to cut emissions by only about 3 percent per year to stay safely under two degrees of warming. If we start today, when global emissions are still growing, the necessary rate is 10 percent. If we delay another decade, it will require us to cut emissions by 30 percent each year. This is why U.N. Secretary-General António Guterres believes we have only one year to change course and get started.

Any number of dead is a tragedy, but more than 10,000 people die each day, globally, from the small-particulate pollution produced by burning carbon.

If the world’s most conspicuous emitters, the top 10 percent, reduced their emissions to only the E.U. average, total global emissions would fall by 35 percent.

the world has, at most, about three decades to completely decarbonize before truly devastating climate horrors begin. You can’t halfway your way to a solution to a crisis this large.

Half of the Great Barrier Reef has already died, methane is leaking from Arctic permafrost that may never freeze again, and the high-end estimates for what warming will mean for cereal crops suggest that just four degrees of warming could reduce yields by 50 percent.

as early as next century, the planet could lose its capacity to produce clouds, which could alone add eight degrees of warming to our total. It may be fatalistic to wonder whether five degrees would bring about the collapse of civilization, or something close to it; it is foolish not to wonder the same about thirteen degrees.

How you assess that future, muddied by some now-unknowable amount of climate suffering, how much it horrifies you and motivates you and angers you and scares you, probably says a lot about how you think about “we,” and “us,” and “them.”