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Drowning

That the sea will become a killer is a given. Barring a reduction of emissions, we could see at least four feet of sea-level rise and possibly eight by the end of the century. A radical reduction—of the scale that could make the Paris two-degree goal a conceivably attainable if quite optimistic target—could still produce as much as two meters, or six feet, by 2100.

Perversely, for a generation now, we’ve been comforted by numbers like these—when we think the worst that climate change can bring is an ocean a few feet higher, anyone who lives even a short distance from the coast feels like they can breathe easy. In that way, even alarmist popular writing about global warming has been a victim of its own success, so focused on sea-level rise that it has blinded readers to all the climate scourges beyond the oceans that threaten to terrorize the coming generations—direct heat, extreme weather, pandemic disease, and more. But as “familiar” as sea-level rise may seem, it surely deserves its place at the center of the picture of what damage climate change will bring. That so many feel already acclimated to the prospect of a near-future world with dramatically higher oceans should be as dispiriting and disconcerting as if we’d already come to accept the inevitability of extended nuclear war—because that is the scale of devastation the rising oceans will unleash.

In The Water Will Come, Jeff Goodell runs through just a few of the monuments—indeed, in some cases, whole cultures—that will be transformed into underwater relics, like sunken ships, this century: any beach you’ve ever visited; Facebook’s headquarters, the Kennedy Space Center, and the United States’ largest naval base, in Norfolk, Virginia; the entire nations of the Maldives and the Marshall Islands; most of Bangladesh, including all of the mangrove forests that have been the kingdom of Bengal tigers for millennia; all of Miami Beach and much of the South Florida paradise engineered out of marsh and swamp and sandbar by rabid real-estate speculators less than a century ago; Saint Mark’s Basilica in Venice, today nearly a thousand years old; Venice Beach and Santa Monica in Los Angeles; the White House at 1600 Pennsylvania Avenue, as well as Trump’s “Winter White House” at Mar-a-Lago, Richard Nixon’s in Key Biscayne, and the original, Harry Truman’s, in Key West. This is a very partial list. We’ve spent the millennia since Plato enamored with the story of a single drowned culture, Atlantis, which if it ever existed was probably a small archipelago of Mediterranean islands with a population numbering in the thousands—possibly tens of thousands. By 2100, if we do not halt emissions, as much as 5 percent of the world’s population will be flooded every single year. Jakarta is one of the world’s fastest-growing cities, today home to ten million; thanks to flooding and literal sinking, it could be entirely underwater as soon as 2050. Already, China is evacuating hundreds of thousands every summer to keep them out of the range of flooding in the Pearl River Delta.

What would be submerged by these floods are not just the homes of those who flee—hundreds of millions of new climate refugees unleashed onto a world incapable, at this point, of accommodating the needs of just a few million—but communities, schools, shopping districts, farmlands, office buildings and high-rises, regional cultures so sprawling that just a few centuries ago we might have remembered them as empires unto themselves, now suddenly underwater museums showcasing the way of life in the one or two centuries when humans, rather than keeping their safe distance, rushed to build up at the coastline. It will take thousands of years, perhaps millions, for quartz and feldspar to degrade into sand that might replenish the beaches we lose.

Much of the infrastructure of the internet, one study showed, could be drowned by sea-level rise in less than two decades; and most of the smartphones we use to navigate it are today manufactured in Shenzhen, which, sitting right in the Pearl River Delta, is likely to be flooded soon, as well. In 2018, the Union of Concerned Scientists found that nearly 311,000 homes in the United States would be at risk of chronic inundation by 2045—a timespan, as they pointed out, no longer than a mortgage. By 2100, the number would be more than 2.4 million properties, or $1 trillion worth of American real estate—underwater. Climate change may not only make the miles along the American coast uninsurable, it could render obsolete the very idea of disaster insurance; by the end of the century, one recent study showed, certain places could be struck by six different climate-driven disasters simultaneously. If no significant action is taken to curb emissions, one estimate of global damages is as high as $100 trillion per year by 2100. That is more than global GDP today. Most estimates are a bit lower: $14 trillion a year, still almost a fifth of present-day GDP.

But the flooding wouldn’t stop at the end of the century, since sea-level rise would continue for millennia, ultimately producing, in even that optimistic two-degree scenario, oceans six meters higher. What would that look like? The planet would lose about 444,000 square miles of land, where about 375 million people live today—a quarter of them in China. In fact, the twenty cities most affected by such sea-level rise are all Asian megalopolises—among them Shanghai, Hong Kong, Mumbai, and Kolkata. Which does cast a climate shroud over the prospect, now so much taken for granted among the Nostradamuses of geopolitics, of an Asian century. Whatever the course of climate change, China will surely continue its ascent, but it will do so while fighting back the ocean, as well—perhaps one reason it is already so focused on establishing control over the South China Sea.

Nearly two-thirds of the world’s major cities are on the coast—not to mention its power plants, ports, navy bases, farmlands, fisheries, river deltas, marshlands, and rice paddies—and even those above ten feet will flood much more easily, and much more regularly, if the water gets that high. Already, flooding has quadrupled since 1980, according to the European Academies’ Science Advisory Council, and doubled since just 2004. Even under an “intermediate low” sea-level-rise scenario, by 2100 high-tide flooding could hit the East Coast of the United States “every other day.” We haven’t even gotten to inland flooding—when rivers run over, swollen by deluges of rain or storm surges channeled downstream from the sea. Between 1995 and 2015, this affected 2.3 billion and killed 157,000 around the world. Under even the most radically aggressive global emissions reduction regime, the further warming of the planet from just the carbon we’ve already pumped into the atmosphere would increase global rainfall to such a degree that the number affected by river flooding in South America would double, according to one paper, from 6 million to 12 million; in Africa, it would grow from 24 to 35 million, and in Asia from 70 to 156 million. All told, at just 1.5 degrees Celsius of warming, flood damage would increase by between 160 and 240 percent; at 2 degrees, the death toll from flooding would be 50 percent higher than today. In the United States, one recent model suggested that FEMA’s recent projections of flood risk were off by a factor of three, and that more than 40 million Americans were at risk of catastrophic inundation.

These effects will come to pass even with a radical reduction of emissions, keep in mind. Without flood adaptation measures, large swaths of northern Europe and the whole eastern half of the United States will be affected by at least ten times as many floods. In large parts of India, Bangladesh, and Southeast Asia, where flooding is today catastrophically common, the multiplier could be just as high—and the baseline is already so elevated that it annually produces humanitarian crises on a scale we like to think we would not forget for generations.

Instead, we forget them immediately. In 2017, floods in South Asia killed 1,200 people, leaving two thirds of Bangladesh underwater; António Guterres, the secretary-general of the United Nations, estimated that 41 million people had been affected. As with so much climate change data, those numbers can numb, but 41 million is as much as eight times the entire global population at the time of the Black Sea deluge 7,600 years ago—reputedly so dramatic and catastrophic a flood that it may have given rise to our Noah’s Ark story. At the same time as the floods hit in 2017, almost 700,000 Rohingya refugees from Myanmar arrived in Bangladesh, most of them in a single settlement site that became, in months, more populous than Lyon, France’s third biggest city, and was erected in the path of landslides just as the next monsoon season arrived.

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To what degree we will be able to adapt to new coastlines is primarily a matter of just how fast the water rises. Our understanding of that timeline has been evolving disconcertingly fast. When the Paris Agreement was drafted, those writing it were sure that the Antarctic ice sheets would remain stable even as the planet warmed several degrees; their expectation was that oceans could rise, at most, only three feet by the end of the century. That was just in 2015. The same year, NASA found that this expectation was hopelessly complacent, suggesting three feet was not a maximum but in fact a minimum. In 2017, the National Oceanic and Atmospheric Administration (NOAA) suggested eight feet was possible—still just in this century. On the East Coast, scientists have already introduced a new term, “sunny day flooding”—when high tide alone, aided by no additional rainstorm, inundates a town.

In 2018, a major study found things accelerating faster still, with the melt rate of the Antarctic ice sheet tripling just in the past decade. From 1992 to 1997, the sheet lost, on average, 49 billion tons of ice each year; from 2012 to 2017, it was 219 billion. In 2016, climate scientist James Hansen had suggested sea level could rise several meters over fifty years, if ice melt doubled every decade; the new paper, keep in mind, registers a tripling, and in the space of just five years. Since the 1950s, the continent has lost 13,000 square miles from its ice shelf; experts say its ultimate fate will probably be determined by what human action is taken in just the next decade.

All climate change is governed by uncertainty, mostly the uncertainty of human action—what action will be taken, and when, to avert or forestall the dramatic transformation of life on the planet that will unfold in the absence of dramatic intervention. Each of our projections, from the most blasé to the most extreme, comes wrapped in doubt—the result of so many estimates and so many assumptions that it would be foolish to take any of them, so to speak, to the bank.

But sea-level rise is different, because on top of the basic mystery of human response it layers much more epistemological ignorance than governs any other aspect of climate change science, save perhaps the question of cloud formation. When water warms, it expands: this we know. But the breaking-up of ice represents almost an entirely new physics, never before observed in human history, and therefore only poorly understood.

There are now, thanks to rapid Arctic melt, papers devoted to what are called the “damage mechanics” of ice-shelf loss. But we do not yet well understand those dynamics, which will be one of the main drivers of sea-level rise, and so cannot yet make confident predictions about how quickly ice sheets will melt. And even though we now have a decent picture of the planet’s climatological past, never in the earth’s entire recorded history has there been warming at anything like this speed—by one estimate, around ten times faster than at any point in the last 66 million years. Every year, the average American emits enough carbon to melt 10,000 tons of ice in the Antarctic ice sheets—enough to add 10,000 cubic meters of water to the ocean. Every minute, each of us adds five gallons.

One study suggests that the Greenland ice sheet could reach a tipping point at just 1.2 degrees of global warming. (We are nearing that temperature level today, already at 1.1 degrees.) Melting that ice sheet alone would, over centuries, raise sea levels six meters, eventually drowning Miami and Manhattan and London and Shanghai and Bangkok and Mumbai. And while business-as-usual emissions trajectories warm the planet by just over 4 degrees by 2100, because temperature changes are unevenly distributed around the planet, they threaten to warm the Arctic by 13.

In 2014, we learned that the West Antarctic and Greenland ice sheets were even more vulnerable to melting than scientists anticipated—in fact, the West Antarctic sheet had already passed a tipping point of collapse, more than doubling its rate of ice loss in just five years. The same had happened in Greenland, where the ice sheet is now losing almost a billion tons of ice every single day. The two sheets contain enough ice to raise global sea levels ten to twenty feet—each. In 2017, it was revealed that two glaciers in the East Antarctic sheet were also losing ice at an alarming rate—eighteen billion tons of ice each year, enough to cover New Jersey in three feet of ice. If both glaciers go, scientists expect, ultimately, an additional 16 feet of water. In total, the two Antarctic ice sheets could raise sea level by 200 feet; in many parts of the world, the shoreline would move by many miles. The last time the earth was four degrees warmer, as Peter Brannen has written, there was no ice at either pole and sea level was 260 feet higher. There were palm trees in the Arctic. Better not to think what that means for life at the equator.

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As with all else in climate, the melting of the planet’s ice will not occur in a vacuum, and scientists do not yet fully understand exactly what cascading effects such collapses will trigger. One major concern is methane, particularly the methane that might be released by a melting Arctic, where permafrost contains up to 1.8 trillion tons of carbon, considerably more than is currently suspended in the earth’s atmosphere. When it thaws, some of it will evaporate as methane, which is, depending on how you measure, at least several dozen times more powerful a greenhouse gas than carbon dioxide.

When I first began seriously researching climate change, the risk from a sudden release of methane from the Arctic permafrost was considered quite low—in fact so low that most scientists derided casual discussion of it as reckless fearmongering and deployed mockingly hyperbolic terms like “Arctic methane time bomb” and “burps of death” to describe what they saw as a climate risk not much worth worrying about in the near term. The news since has not been encouraging: one Nature paper found that the release of Arctic methane from permafrost lakes could be rapidly accelerated by bursts of what is called “abrupt thawing,” already under way. Atmospheric methane levels have risen dramatically in recent years, confusing scientists unsure of their source; new research suggests the amount of gas being released by Arctic lakes could possibly double going forward. It’s not clear whether this methane release is new or just that we finally began to pay attention to it. But while the consensus is still that a rapid, sudden release of methane is unlikely, the new research is a case study in why it is worthwhile to consider, and take seriously, such unlikely-but-possible climate risks. When you define anything outside a narrow band of likelihood as irresponsible to consider, or talk about, or plan for, even unspectacular new research findings can catch you flat-footed.

Today, all do agree that that permafrost is melting—the permafrost line having retreated eighty miles north in Canada over the last fifty years. The most recent IPCC assessment projects a loss of near-surface permafrost of between 37 and 81 percent by 2100, though most scientists still believe that carbon will be released slowly, and mostly as less-terrifying carbon dioxide. But as far back as 2011, NOAA and the National Snow and Ice Data Center predicted that thawing permafrost would flip the whole region from being what is called a carbon sink, which absorbs atmospheric carbon, to a carbon source, which releases carbon, as quickly as the 2020s. By 2100, the same study said, the Arctic will have released a hundred billion tons of carbon. That is the equivalent of half of all the carbon produced by humanity since industrialization began.

Remember, that is the Arctic feedback loop that does not much concern many climate scientists in the near term. The one that concerns them more, at present, is what is called the “albedo effect”: ice is white and so reflects sunlight back into space rather than absorbing it; the less ice, the more sunlight is absorbed as global warming; and the total disappearance of that ice, Peter Wadhams has estimated, could mean a massive warming equivalent to the entire last twenty-five years of global carbon emissions. The last twenty-five years of emissions, keep in mind, is about half of the total that humanity has ever produced—a scale of carbon production that has pushed the planet from near-complete climate stability to the brink of chaos.

All of this is speculative. But our uncertainty over each of these dynamics—ice sheet collapse, Arctic methane, the albedo effect—clouds our understanding only of the pace of change, not its scale. In fact, we do know what the endgame for oceans looks like, just not how long it will take us to get there.

How much sea-level rise is that? The ocean chemist David Archer is the researcher who has focused perhaps most acutely on what he calls the “long thaw” impacts of global warming. It may take centuries, he says, even millennia, but he estimates that ultimately, even at just three degrees of warming, sea-level rise will be at least fifty meters—that is, fully one hundred times higher than Paris predicted for 2100. The U.S. Geological Survey puts the ultimate figure at eighty meters, or more than 260 feet.

The world would perhaps not be made literally unrecognizable by that flooding, but the distinction is ultimately semantic. Montreal would be almost entirely underwater, as would London. The United States is an unexceptional example: at just 170 feet, more than 97 percent of Florida would disappear, leaving only a few hills in the Panhandle; and just under 97 percent of Delaware would be submerged. Oceans would cover 80 percent of Louisiana, 70 percent of New Jersey, and half of South Carolina, Rhode Island, and Maryland. San Francisco and Sacramento would be underwater, as would New York City, Philadelphia, Providence, Houston, Seattle, and Virginia Beach, among dozens of other cities. In many places, the coast would retreat by as much as one hundred miles. Arkansas and Vermont, landlocked today, would become coastal.

The rest of the world may fare even worse. Manaus, the capital of the Brazilian Amazon, would not just be on the oceanfront, but underneath its waters, as would Buenos Aires and the biggest city in landlocked Paraguay, Asunción, now more than five hundred miles inland. In Europe, in addition to London, Dublin would be underwater, as would Brussels, Amsterdam, Copenhagen and Stockholm, Riga and Helsinki and Saint Petersburg. Istanbul would flood, and the Black Sea and the Mediterranean would join. In Asia, you could forget the coastline cities of Doha and Dubai and Karachi and Kolkata and Mumbai (to name just a few) and would be able to trace the trail of underwater metropolises from what is now close to desert, in Baghdad, all the way to Beijing, itself a hundred miles inland.

That 260-foot rise is, ultimately, the ceiling—but it is a pretty good bet we will get there eventually. Greenhouse gases simply work on too long a timescale to avoid it, though what kind of human civilization will be around to see that flooded planet is very much to be determined. Of course, the scariest variable is how quickly that flood will come. Perhaps it will be a thousand years, but perhaps much sooner. More than 600 million people live within thirty feet of sea level today.