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If the world had adopted the proposal widely endorsed at the end of the ’80s — a freezing of carbon emissions, with a reduction of 20 percent by 2005 — warming could have been held to less than 1.5 degrees.

Action had to be taken, and the United States would need to lead. It didn’t.

There can be no understanding of our current and future predicament without understanding why we failed to solve this problem when we had the chance.

The first suggestion to Rafe Pomerance that humankind was destroying the conditions necessary for its own survival came on Page 66 of the government publication EPA-600/7-78-019. It was a technical report about coal

‘This Is the Whole Banana’ Spring 1979

here was an urgent problem that demanded their attention, MacDonald believed, because human civilization faced an existential crisis. In “How to Wreck the Environment,” a 1968 essay published while he was a science adviser to Lyndon Johnson, MacDonald predicted a near future in which “nuclear weapons were effectively banned and the weapons of mass destruction were those of environmental catastrophe.” One of the most potentially devastating such weapons, he believed, was the gas that we exhaled with every breath: carbon dioxide. By vastly increasing carbon emissions, the world’s most advanced militaries could alter weather patterns and wreak famine, drought and economic collapse.

the Jasons. They were like one of those teams of superheroes with complementary powers that join forces in times of galactic crisis. They had been brought together by federal agencies, including the C.I.A, to devise scientific solutions to national-security problems: how to detect an incoming missile; how to predict fallout from a nuclear bomb; how to develop unconventional weapons, like plague-infested rats.

Agle pointed to an article about a prominent geophysicist named Gordon MacDonald, who was conducting a study on climate change with the Jasons, the mysterious coterie of elite scientists to which he belonged

During the spring of 1977 and the summer of 1978, the Jasons met to determine what would happen once the concentration of carbon dioxide in the atmosphere doubled from pre-Industrial Revolution levels. It was an arbitrary milestone, the doubling, but a useful one, as its inevitability was not in question; the threshold would most likely be breached by 2035.

The Jasons’ report to the Department of Energy, “The Long-Term Impact of Atmospheric Carbon Dioxide on Climate,” was written in an understated tone that only enhanced its nightmarish findings: Global temperatures would increase by an average of two to three degrees Celsius; Dust Bowl conditions would “threaten large areas of North America, Asia and Africa”; access to drinking water and agricultural production would fall, triggering mass migration on an unprecedented scale. “Perhaps the most ominous feature,” however, was the effect of a changing climate on the poles. Even a minimal warming “could lead to rapid melting” of the West Antarctic ice sheet. The ice sheet contained enough water to raise the level of the oceans 16 feet.

MacDonald explained that he first studied the carbon-dioxide issue when he was about Pomerance’s age — in 1961, when he served as an adviser to John F. Kennedy. Pomerance pieced together that MacDonald, in his youth, had been something of a prodigy: In his 20s, he advised Dwight D. Eisenhower on space exploration; at 32, he became a member of the National Academy of Sciences; at 40, he was appointed to the inaugural Council on Environmental Quality, where he advised Richard Nixon on the environmental dangers of burning coal. He monitored the carbon-dioxide problem the whole time, with increasing alarm.

They were surprised to learn how few senior officials were familiar with the Jasons’ findings, let alone understood the ramifications of global warming. At last, having worked their way up the federal hierarchy, the two went to see the president’s top scientist, Frank Press.

Thus began the Gordon and Rafe carbon-dioxide roadshow. Beginning in the spring of 1979, Pomerance arranged informal briefings with the E.P.A., the National Security Council, The New York Times, the Council on Environmental Quality and the Energy Department, which, Pomerance learned, had established an Office of Carbon Dioxide Effects two years earlier at MacDonald’s urging

. Out of respect for MacDonald, Press had summoned to their meeting what seemed to be the entire senior staff of the president’s Office of Science and Technology Policy — the officials consulted on every critical matter of energy and national security. What Pomerance had expected to be yet another casual briefing assumed the character of a high-level national-security meeting.

MacDonald would begin his presentation by going back more than a century to John Tyndall — an Irish physicist who was an early champion of Charles Darwin’s work and died after being accidentally poisoned by his wife. In 1859, Tyndall found that carbon dioxide absorbed heat and that variations in the composition of the atmosphere could create changes in climate. These findings inspired Svante Arrhenius, a Swedish chemist and future Nobel laureate, to deduce in 1896 that the combustion of coal and petroleum could raise global temperatures. This warming would become noticeable in a few centuries, Arrhenius calculated, or sooner if consumption of fossil fuels continued to increase.

Four decades later, a British steam engineer named Guy Stewart Callendar discovered that, at the weather stations he observed, the previous five years were the hottest in recorded history. Humankind, he wrote in a paper, had become “able to speed up the processes of Nature.” That was in 1939.

MacDonald’s history concluded with Roger Revelle, perhaps the most distinguished of the priestly caste of government scientists who, since the Manhattan Project, advised every president on major policy; he had been a close colleague of MacDonald and Press since they served together under Kennedy. In a 1957 paper written with Hans Suess, Revelle concluded that “human beings are now carrying out a large-scale geophysical experiment of a kind that could not have happened in the past nor be reproduced in the future.” Revelle helped the Weather Bureau establish a continuous measurement of atmospheric carbon dioxide at a site perched near the summit of Mauna Loa on the Big Island of Hawaii, 11,500 feet above the sea — a rare pristine natural laboratory on a planet blanketed by fossil-fuel emissions.

After nearly a decade of observation, Revelle had shared his concerns with Lyndon Johnson, who included them in a special message to Congress two weeks after his inauguration. Johnson explained that his generation had “altered the composition of the atmosphere on a global scale” through the burning of fossil fuels, and his administration commissioned a study of the subject by his Science Advisory Committee. Revelle was its chairman, and its 1965 executive report on carbon dioxide warned of the rapid melting of Antarctica, rising seas, increased acidity of fresh waters — changes that would require no less than a coordinated global effort to forestall.Yet emissions continued to rise, and at this rate, MacDonald warned, they could see a snowless New England, the swamping of major coastal cities, as much as a 40 percent decline in national wheat production, the forced migration of about one-quarter of the world’s population. Not within centuries — within their own lifetimes.

On May 22, Press wrote a letter to the president of the National Academy of Sciences requesting a full assessment of the carbon-dioxide issue. Jule Charney, the father of modern meteorology, would gather the nation’s top oceanographers, atmospheric scientists and climate modelers to judge whether MacDonald’s alarm was justified — whether the world was, in fact, headed to cataclysm.

If Charney’s group confirmed that the world was careering toward an existential crisis, the president would be forced to act.

Hansen turned from the moon to Venus. Why, he tried to determine, was its surface so hot? In 1967, a Soviet satellite beamed back the answer: The planet’s atmosphere was mainly carbon dioxide. Though once it may have had habitable temperatures, it was believed to have succumbed to a runaway greenhouse effect: As the sun grew brighter, Venus’s ocean began to evaporate, thickening the atmosphere, which forced yet greater evaporation — a self-perpetuating cycle that finally boiled off the ocean entirely and heated the planet’s surface to more than 800 degrees Fahrenheit

At the other extreme, Mars’s thin atmosphere had insufficient carbon dioxide to trap much heat at all, leaving it about 900 degrees colder. Earth lay in the middle, its Goldilocks greenhouse effect just strong enough to support life.

We want to learn more about Earth’s climate, Jim told Anniek — and how humanity can influence it. He would use giant new supercomputers to map the planet’s atmosphere. They would create Mirror Worlds: parallel realities that mimicked our own. These digital simulacra, technically called “general circulation models,” combined the mathematical formulas that governed the behavior of the sea, land and sky into a single computer model. Unlike the real world, they could be sped forward to reveal the future.

The government officials, many of them scientists themselves, tried to suppress their awe of the legends in their presence: Henry Stommel, the world’s leading oceanographer; his protégé, Carl Wunsch, a Jason; the Manhattan Project alumnus Cecil Leith; the Harvard planetary physicist Richard Goody. These were the men who, in the last three decades, had discovered foundational principles underlying the relationships among sun, atmosphere, land and ocean — which is to say, the climate.

When, at Charney’s request, Hansen programmed his model to consider a future of doubled carbon dioxide, it predicted a temperature increase of four degrees Celsius. That was twice as much warming as the prediction made by the most prominent climate modeler, Syukuro Manabe, whose government lab at Princeton was the first to model the greenhouse effect. The difference between the two predictions — between warming of two degrees Celsius and four degrees Celsius — was the difference between damaged coral reefs and no reefs whatsoever, between thinning forests and forests enveloped by desert, between catastrophe and chaos.

The discrepancy between the models, Arakawa concluded, came down to ice and snow. The whiteness of the world’s snowfields reflected light; if snow melted in a warmer climate, less radiation would escape the atmosphere, leading to even greater warming. Shortly before dawn, Arakawa concluded that Manabe had given too little weight to the influence of melting sea ice, while Hansen had overemphasized it. The best estimate lay in between. Which meant that the Jasons’ calculation was too optimistic. When carbon dioxide doubled in 2035 or thereabouts, global temperatures would increase between 1.5 and 4.5 degrees Celsius, with the most likely outcome a warming of three degrees.

within the highest levels of the federal government, the scientific community and the oil-and-gas industry — within the commonwealth of people who had begun to concern themselves with the future habitability of the planet — the Charney report would come to have the authority of settled fact. It was the summation of all the predictions that had come before, and it would withstand the scrutiny of the decades that followed it. Charney’s group had considered everything known about ocean, sun, sea, air and fossil fuels and had distilled it to a single number: three. When the doubling threshold was broached, as appeared inevitable, the world would warm three degrees Celsius

The last time the world was three degrees warmer was during the Pliocene, three million years ago, when beech trees grew in Antarctica, the seas were 80 feet higher and horses galloped across the Canadian coast of the Arctic Ocean.

After the publication of the Charney report, Exxon decided to create its own dedicated carbon-dioxide research program, with an annual budget of $600,000. Only Exxon was asking a slightly different question than Jule Charney. Exxon didn’t concern itself primarily with how much the world would warm. It wanted to know how much of the warming Exxon could be blamed for.

“It behooves us to start a very aggressive defensive program,” Shaw wrote in a memo to a manager, “because there is a good probability that legislation affecting our business will be passed.”

Shaw turned to Wallace Broecker, a Columbia University oceanographer who was the second author of Roger Revelle’s 1965 carbon-dioxide report for Lyndon Johnson. In 1977, in a presentation at the American Geophysical Union, Broecker predicted that fossil fuels would have to be restricted, whether by taxation or fiat. More recently, he had testified before Congress, calling carbon dioxide “the No.1 long-term environmental problem.” If presidents and senators trusted Broecker to tell them the bad news, he was good enough for Exxon.

The company had been studying the carbon-dioxide problem for decades, since before it changed its name to Exxon. In 1957, scientists from Humble Oil published a study tracking “the enormous quantity of carbon dioxide” contributed to the atmosphere since the Industrial Revolution “from the combustion of fossil fuels.” Even then, the observation that burning fossil fuels had increased the concentration of carbon in the atmosphere was well understood and accepted by Humble’s scientists.

The American Petroleum Institute, the industry’s largest trade association, asked the same question in 1958 through its air-pollution study group and replicated the findings made by Humble Oil. So did another A.P.I. study conducted by the Stanford Research Institute a decade later, in 1968, which concluded that the burning of fossil fuels would bring “significant temperature changes” by the year 2000 and ultimately “serious worldwide environmental changes,” including the melting of the Antarctic ice cap and rising seas.

The ritual repeated itself every few years. Industry scientists, at the behest of their corporate bosses, reviewed the problem and found good reasons for alarm and better excuses to do nothing. Why should they act when almost nobody within the United States government — nor, for that matter, within the environmental movement — seemed worried?

Why take on an intractable problem that would not be detected until this generation of employees was safely retired? Worse, the solutions seemed more punitive than the problem itself. Historically, energy use had correlated to economic growth — the more fossil fuels we burned, the better our lives became. Why mess with that?

That June, Jimmy Carter signed the Energy Security Act of 1980, which directed the National Academy of Sciences to start a multiyear, comprehensive study, to be called “Changing Climate,” that would analyze social and economic effects of climate change. More urgent, the National Commission on Air Quality, at the request of Congress, invited two dozen experts, including Henry Shaw himself, to a meeting in Florida to propose climate policy.

On April 3, 1980, Senator Paul Tsongas, a Massachusetts Democrat, held the first congressional hearing on carbon-dioxide buildup in the atmosphere. Gordon MacDonald testified that the United States should “take the initiative” and develop, through the United Nations, a way to coordinate every nation’s energy policies to address the problem.

During the expansion of the Clean Air Act, he pushed for the creation of the National Commission on Air Quality, charged with ensuring that the goals of the act were being met. One such goal was a stable global climate. The Charney report had made clear that goal was not being met, and now the commission wanted to hear proposals for legislation. It was a profound responsibility, and the two dozen experts invited to the Pink Palace — policy gurus, deep thinkers, an industry scientist and an environmental activist — had only three days to achieve it, but the utopian setting made everything seem possible

We have less time than we realize, said an M.I.T. nuclear engineer named David Rose, who studied how civilizations responded to large technological crises. “People leave their problems until the 11th hour, the 59th minute,” he said. “And then: ‘Eloi, Eloi, Lama Sabachthani?’ ” — “My God, my God, why hast thou forsaken me?”

The attendees seemed to share a sincere interest in finding solutions. They agreed that some kind of international treaty would ultimately be needed to keep atmospheric carbon dioxide at a safe level. But nobody could agree on what that level was.

William Elliott, a NOAA scientist, introduced some hard facts: If the United States stopped burning carbon that year, it would delay the arrival of the doubling threshold by only five years. If Western nations somehow managed to stabilize emissions, it would forestall the inevitable by only eight years. The only way to avoid the worst was to stop burning coal. Yet China, the Soviet Union and the United States, by far the world’s three largest coal producers, were frantically accelerating extraction.

“Do we have a problem?” asked Anthony Scoville, a congressional science consultant. “We do, but it is not the atmospheric problem. It is the political problem.” He doubted that any scientific report, no matter how ominous its predictions, would persuade politicians to act.

The talk of ending oil production stirred for the first time the gentleman from Exxon. “I think there is a transition period,” Henry Shaw said. “We are not going to stop burning fossil fuels and start looking toward solar or nuclear fusion and so on. We are going to have a very orderly transition from fossil fuels to renewable energy sources.”

What if the problem was that they were thinking of it as a problem? “What I am saying,” Scoville continued, “is that in a sense we are making a transition not only in energy but the economy as a whole.” Even if the coal and oil industries collapsed, renewable technologies like solar energy would take their place. Jimmy Carter was planning to invest $80 billion in synthetic fuel. “My God,” Scoville said, “with $80 billion, you could have a photovoltaics industry going that would obviate the need for synfuels forever!”

nobody could agree what to do. John Perry, a meteorologist who had worked as a staff member on the Charney report, suggested that American energy policy merely “take into account” the risks of global warming, though he acknowledged that a nonbinding measure might seem “intolerably stodgy.” “It is so weak,” Pomerance said, the air seeping out of him, “as to not get us anywhere.”

Scoville pointed out that the United States was responsible for the largest share of global carbon emissions. But not for long. “If we’re going to exercise leadership,” he said, “the opportunity is now.

One way to lead, he proposed, would be to classify carbon dioxide as a pollutant under the Clean Air Act and regulate it as such. This was received by the room like a belch. By Scoville’s logic, every sigh was an act of pollution. Did the science really support such an extreme measure? The Charney report did exactly that, Pomerance said.

Slade, the director of the Energy Department’s carbon-dioxide program, considered the lag a saving grace. If changes did not occur for a decade or more, he said, those in the room couldn’t be blamed for failing to prevent them. So what was the problem?

“Call it whatever.” Besides, Pomerance added, they didn’t have to ban coal tomorrow. A pair of modest steps could be taken immediately to show the world that the United States was serious: the implementation of a carbon tax and increased investment in renewable energy. Then the United States could organize an international summit meeting to address climate change

these two dozen experts, who agreed on the major points and had made a commitment to Congress, could not draft a single paragraph. Hours passed in a hell of fruitless negotiation, self-defeating proposals and impulsive speechifying. Pomerance and Scoville pushed to include a statement calling for the United States to “sharply accelerate international dialogue,” but they were sunk by objections and caveats.

They never got to policy proposals. They never got to the second paragraph. The final statement was signed by only the moderator, who phrased it more weakly than the declaration calling for the workshop in the first place. “The guide I would suggest,” Jorling wrote, “is whether we know enough not to recommend changes in existing policy.”

Pomerance had seen enough. A consensus-based strategy would not work — could not work — without American leadership. And the United States wouldn’t act unless a strong leader persuaded it to do so — someone who would speak with authority about the science, demand action from those in power and risk everything in pursuit of justice.

The meeting ended Friday morning. On Tuesday, four days later, Ronald Reagan was elected president.

‘Otherwise, They’ll Gurgle’ November 1980-September 1981

In the midst of this carnage, the Council on Environmental Quality submitted a report to the White House warning that fossil fuels could “permanently and disastrously” alter Earth’s atmosphere, leading to “a warming of the Earth, possibly with very serious effects.” Reagan did not act on the council’s advice. Instead, his administration considered eliminating the council.

After the election, Reagan considered plans to close the Energy Department, increase coal production on federal land and deregulate surface coal mining. Once in office, he appointed James Watt, the president of a legal firm that fought to open public lands to mining and drilling, to run the Interior Department. “We’re deliriously happy,” the president of the National Coal Association was reported to have said. Reagan preserved the E.P.A. but named as its administrator Anne Gorsuch, an anti-regulation zealot who proceeded to cut the agency’s staff and budget by about a quarter

Reagan “has declared open war on solar energy,” the director of the nation’s lead solar-energy research agency said, after he was asked to resign). Reagan appeared determined to reverse the environmental achievements of Jimmy Carter, before undoing those of Richard Nixon, Lyndon Johnson, John F. Kennedy and, if he could get away with it, Theodore Roosevelt.

When Reagan considered closing the Council on Environmental Quality, its acting chairman, Malcolm Forbes Baldwin, wrote to the vice president and the White House chief of staff begging them to reconsider; in a major speech the same week, “A Conservative’s Program for the Environment,” Baldwin argued that it was “time for today’s conservatives explicitly to embrace environmentalism.” Environmental protection was not only good sense. It was good business. What could be more conservative than an efficient use of resources that led to fewer federal subsidies?

Meanwhile the Charney report continued to vibrate at the periphery of public consciousness. Its conclusions were confirmed by major studies from the Aspen Institute, the International Institute for Applied Systems Analysis near Vienna and the American Association for the Advancement of Science. Every month or so, nationally syndicated articles appeared summoning apocalypse: “Another Warning on ‘Greenhouse Effect,’ ” “Global Warming Trend ‘Beyond Human Experience,’ ” “Warming Trend Could ‘Pit Nation Against Nation.’

Pomerance read on the front page of The New York Times on Aug. 22, 1981, about a forthcoming paper in Science by a team of seven NASA scientists. They had found that the world had already warmed in the past century. Temperatures hadn’t increased beyond the range of historical averages, but the scientists predicted that the warming signal would emerge from the noise of routine weather fluctuations much sooner than previously expected. Most unusual of all, the paper ended with a policy recommendation: In the coming decades, the authors wrote, humankind should develop alternative sources of energy and use fossil fuels only “as necessary.” The lead author was James Hansen.

Pomerance listened and watched. He understood Hansen’s basic findings well enough: Earth had been warming since 1880, and the warming would reach “almost unprecedented magnitude” in the next century, leading to the familiar suite of terrors, including the flooding of a 10th of New Jersey and a quarter of Louisiana and Florida. But Pomerance was excited to find that Hansen could translate the complexities of atmospheric science into plain English.

7. ‘We’re All Going to Be the Victims’ March 1982

Gore had learned about climate change a dozen years earlier as an undergraduate at Harvard, when he took a class taught by Roger Revelle. Humankind was on the brink of radically transforming the global atmosphere, Revelle explained, drawing Keeling’s rising zigzag on the blackboard, and risked bringing about the collapse of civilization. Gore was stunned: Why wasn’t anyone talking about this?

Most in Congress considered the science committee a legislative backwater, if they considered it at all; this made Gore’s subcommittee, which had no legislative authority, an afterthought to an afterthought. That, Gore vowed, would change. Environmental and health stories had all the elements of narrative drama: villains, victims and heroes. In a hearing, you could summon all three, with the chairman serving as narrator, chorus and moral authority. He told his staff director that he wanted to hold a hearing every week.

The Revelle hearing went as Grumbly had predicted. The urgency of the issue was lost on Gore’s older colleagues, who drifted in and out while the witnesses testified. There were few people left by the time the Brookings Institution economist Lester Lave warned that humankind’s profligate exploitation of fossil fuels posed an existential test to human nature. “Carbon dioxide stands as a symbol now of our willingness to confront the future,” he said. “It will be a sad day when we decide that we just don’t have the time or thoughtfulness to address those issues.”

That night, the news programs featured the resolution of the baseball strike, the ongoing budgetary debate and the national surplus of butter.

There emerged, despite the general comity, a partisan divide. Unlike the Democrats, the Republicans demanded action. “Today I have a sense of déjà vu,” said Robert Walker, a Republican from Pennsylvania. In each of the last five years, he said, “we have been told and told and told that there is a problem with the increasing carbon dioxide in the atmosphere. We all accept that fact, and we realize that the potential consequences are certainly major in their impact on mankind.” Yet they had failed to propose a single law. “Now is the time,” he said. “The research is clear. It is up to us now to summon the political will.”

Hansen flew to Washington to testify on March 25, 1982, performing before a gallery even more thinly populated than at Gore’s first hearing on the greenhouse effect. Gore began by attacking the Reagan administration for cutting funding for carbon-dioxide research despite the “broad consensus in the scientific community that the greenhouse effect is a reality.” William Carney, a Republican from New York, bemoaned the burning of fossil fuels and argued passionately that science should serve as the basis for legislative policy

the experts invited by Gore agreed with the Republicans: The science was certain enough. Melvin Calvin, a Berkeley chemist who won the Nobel Prize for his work on the carbon cycle, said that it was useless to wait for stronger evidence of warming. “You cannot do a thing about it when the signals are so big that they come out of the noise,” he said. “You have to look for early warning signs.”

Hansen’s job was to share the warning signs, to translate the data into plain English. He explained a few discoveries that his team had made — not with computer models but in libraries. By analyzing records from hundreds of weather stations, he found that the surface temperature of the planet had already increased four-tenths of a degree Celsius in the previous century. Data from several hundred tide-gauge stations showed that the oceans had risen four inches since the 1880s

It occurred to Hansen that this was the only political question that mattered: How long until the worst began? It was not a question on which geophysicists expended much effort; the difference between five years and 50 years in the future was meaningless in geologic time. Politicians were capable of thinking only in terms of electoral time: six years, four years, two years. But when it came to the carbon problem, the two time schemes were converging.

“Within 10 or 20 years,” Hansen said, “we will see climate changes which are clearly larger than the natural variability.” James Scheuer wanted to make sure he understood this correctly. No one else had predicted that the signal would emerge that quickly. “If it were one or two degrees per century,” he said, “that would be within the range of human adaptability. But we are pushing beyond the range of human adaptability.” “Yes,” Hansen said.

How soon, Scheuer asked, would they have to change the national model of energy production? Hansen hesitated — it wasn’t a scientific question. But he couldn’t help himself. He had been irritated, during the hearing, by all the ludicrous talk about the possibility of growing more trees to offset emissions. False hopes were worse than no hope at all: They undermined the prospect of developing real solutions. “That time is very soon,” Hansen said finally. “My opinion is that it is past,” Calvin said, but he was not heard because he spoke from his seat. He was told to speak into the microphone. “It is already later,” Calvin said, “than you think.”

From Gore’s perspective, the hearing was an unequivocal success. That night Dan Rather devoted three minutes of “CBS Evening News” to the greenhouse effect. A correspondent explained that temperatures had increased over the previous century, great sheets of pack ice in Antarctica were rapidly melting, the seas were rising; Calvin said that “the trend is all in the direction of an impending catastrophe”; and Gore mocked Reagan for his shortsightedness. Later, Gore could take credit for protecting the Energy Department’s carbon-dioxide program, which in the end was largely preserved.

8. ‘The Direction of an Impending Catastrophe’ 1982

Following Henry Shaw’s recommendation to establish credibility ahead of any future legislative battles, Exxon had begun to spend conspicuously on global-warming research. It donated tens of thousands of dollars to some of the most prominent research efforts, including one at Woods Hole led by the ecologist George Woodwell, who had been calling for major climate policy as early as the mid-1970s, and an international effort coordinated by the United Nations. Now Shaw offered to fund the October 1982 symposium on climate change at Columbia’s Lamont-Doherty campus.

David boasted that Exxon would usher in a new global energy system to save the planet from the ravages of climate change. He went so far as to argue that capitalism’s blind faith in the wisdom of the free market was “less than satisfying” when it came to the greenhouse effect. Ethical considerations were necessary, too. He pledged that Exxon would revise its corporate strategy to account for climate change, even if it were not “fashionable” to do so. As Exxon had already made heavy investments in nuclear and solar technology, he was “generally upbeat” that Exxon would “invent” a future of renewable energy.

Hansen had reason to feel upbeat himself. If the world’s largest oil-and-gas company supported a new national energy model, the White House would not stand in its way. The Reagan administration was hostile to change from within its ranks. But it couldn’t be hostile to Exxon.

The carbon-dioxide issue was beginning to receive major national attention — Hansen’s own findings had become front-page news, after all. What started as a scientific story was turning into a political story.

The political realm was itself a kind of Mirror World, a parallel reality that crudely mimicked our own. It shared many of our most fundamental laws, like the laws of gravity and inertia and publicity. And if you applied enough pressure, the Mirror World of politics could be sped forward to reveal a new future. Hansen was beginning to understand that too.

1. ‘Caution, Not Panic’ 1983-1984

in the fall of 1983, the climate issue entered an especially long, dark winter. And all because of a single report that had done nothing to change the state of climate science but transformed the state of climate politics.

After the publication of the Charney report in 1979, Jimmy Carter had directed the National Academy of Sciences to prepare a comprehensive, $1 million analysis of the carbon-dioxide problem: a Warren Commission for the greenhouse effect. A team of scientist-dignitaries — among them Revelle, the Princeton modeler Syukuro Manabe and the Harvard political economist Thomas Schelling, one of the intellectual architects of Cold War game theory — would review the literature, evaluate the consequences of global warming for the world order and propose remedies

Then Reagan won the White House.

the incipient report served as the Reagan administration’s answer to every question on the subject. There could be no climate policy, Fred Koomanoff and his associates said, until the academy ruled. In the Mirror World of the Reagan administration, the warming problem hadn’t been abandoned at all. A careful, comprehensive solution was being devised. Everyone just had to wait for the academy’s elders to explain what it was.

The committee’s chairman, William Nierenberg — a Jason, presidential adviser and director of Scripps, the nation’s pre-eminent oceanographic institution — argued that action had to be taken immediately, before all the details could be known with certainty, or else it would be too late.

Better to bet on American ingenuity to save the day. Major interventions in national energy policy, taken immediately, might end up being more expensive, and less effective, than actions taken decades in the future, after more was understood about the economic and social consequences of a warmer planet. Yes, the climate would change, mostly for the worst, but future generations would be better equipped to change with it.

Government officials who knew Nierenberg were not surprised by his conclusions: He was an optimist by training and experience, a devout believer in the doctrine of American exceptionalism, one of the elite class of scientists who had helped the nation win a global war, invent the most deadly weapon conceivable and create the booming aerospace and computer industries. America had solved every existential problem it had confronted over the previous generation; it would not be daunted by an excess of carbon dioxide. Nierenberg had also served on Reagan’s transition team. Nobody believed that he had been directly influenced by his political connections, but his views — optimistic about the saving graces of market forces, pessimistic about the value of government regulation — reflected all the ardor of his party.

That’s what Nierenberg wrote in “Changing Climate.” But it’s not what he said in the press interviews that followed. He argued the opposite: There was no urgent need for action. The public should not entertain the most “extreme negative speculations” about climate change (despite the fact that many of those speculations appeared in his report). Though “Changing Climate” urged an accelerated transition to renewable fuels, noting that it would take thousands of years for the atmosphere to recover from the damage of the last century, Nierenberg recommended “caution, not panic.” Better to wait and see

The damage of “Changing Climate” was squared by the amount of attention it received. Nierenberg’s speech in the Great Hall, being one-500th the length of the actual assessment, received 500 times the press coverage. As The Wall Street Journal put it, in a line echoed by trade journals across the nation: “A panel of top scientists has some advice for people worried about the much-publicized warming of the Earth’s climate: You can cope.”

On “CBS Evening News,” Dan Rather said the academy had given “a cold shoulder” to a grim, 200-page E.P.A. assessment published earlier that week (titled “Can We Delay a Greenhouse Warming?”; the E.P.A.’s answer, reduced to a word, was no). The Washington Post described the two reports, taken together, as “clarion calls to inaction.

George Keyworth II, Reagan’s science adviser. Keyworth used Nierenberg’s optimism as reason to discount the E.P.A.’s “unwarranted and unnecessarily alarmist” report and warned against taking any “near-term corrective action” on global warming. Just in case it wasn’t clear, Keyworth added, “there are no actions recommended other than continued research.”

Edward David Jr., two years removed from boasting of Exxon’s commitment to transforming global energy policy, told Science that the corporation had reconsidered. “Exxon has reverted to being mainly a supplier of conventional hydrocarbon fuels — petroleum products, natural gas and steam coal,” David said. The American Petroleum Institute canceled its own carbon-dioxide research program, too.

Exxon soon revised its position on climate-change research. In a presentation at an industry conference, Henry Shaw cited “Changing Climate” as evidence that “the general consensus is that society has sufficient time to technologically adapt to a CO₂ greenhouse effect.” If the academy had concluded that regulations were not a serious option, why should Exxon protest

2. ‘You Scientists Win’ 1985

3. The Size of The Human Imagination Spring-Summer 1986

Curtis Moore’s proposal: Use ozone to revive climate. The ozone hole had a solution — an international treaty, already in negotiation. Why not hitch the milk wagon to the bullet train? Pomerance was skeptical. The problems were related, sure: Without a reduction in CFC emissions, you didn’t have a chance of averting cataclysmic global warming. But it had been difficult enough to explain the carbon issue to politicians and journalists; why complicate the sales pitch? Then again, he didn’t see what choice he had. The Republicans controlled the Senate, and Moore was his connection to the Senate’s environmental committee.

Pomerance met with Senator John Chafee, a Republican from Rhode Island, and helped persuade him to hold a double-barreled hearing on the twin problems of ozone and carbon dioxide on June 10 and 11, 1986

F.Sherwood Rowland, Robert Watson, a NASA scientist, and Richard Benedick, the administration’s lead representative in international ozone negotiations, would discuss ozone; James Hansen, Al Gore, the ecologist George Woodwell and Carl Wunsch, a veteran of the Charney group, would testify about climate change.

As Pomerance had hoped, fear about the ozone layer ensured a bounty of press coverage for the climate-change testimony. But as he had feared, it caused many people to conflate the two crises. One was Peter Jennings, who aired the video on ABC’s “World News Tonight,” warning that the ozone hole “could lead to flooding all over the world, also to drought and to famine.”

The confusion helped: For the first time since the “Changing Climate” report, global-warming headlines appeared by the dozen. William Nierenberg’s “caution, not panic” line was inverted. It was all panic without a hint of caution: “A Dire Forecast for ‘Greenhouse’ Earth” (the front page of The Washington Post); “Scientists Predict Catastrophes in Growing Global Heat Wave” (Chicago Tribune); “Swifter Warming of Globe Foreseen” (The New York Times).

After three years of backsliding and silence, Pomerance was exhilarated to see interest in the issue spike overnight. Not only that: A solution materialized, and a moral argument was passionately articulated — by Rhode Island’s Republican senator no less. “Ozone depletion and the greenhouse effect can no longer be treated solely as important scientific questions,” Chafee said. “They must be seen as critical problems facing the nations of the world, and they are problems that demand solutions.”

The old canard about the need for more research was roundly mocked — by Woodwell, by a W.R.I. colleague named Andrew Maguire, by Senator George Mitchell, a Democrat from Maine. “Scientists are never 100 percent certain,” the Princeton historian Theodore Rabb testified. “That notion of total certainty is something too elusive ever to be sought.” As Pomerance had been saying since 1979, it was past time to act. Only now the argument was so broadly accepted that nobody dared object.

The ozone hole, Pomerance realized, had moved the public because, though it was no more visible than global warming, people could be made to see it. They could watch it grow on video. Its metaphors were emotionally wrought: Instead of summoning a glass building that sheltered plants from chilly weather (“Everything seems to flourish in there”), the hole evoked a violent rending of the firmament, inviting deathly radiation. Americans felt that their lives were in danger. An abstract, atmospheric problem had been reduced to the size of the human imagination. It had been made just small enough, and just large enough, to break through.

Four years after “Changing Climate,” two years after a hole had torn open the firmament and a month after the United States and more than three dozen other nations signed a treaty to limit use of CFCs, the climate-change corps was ready to celebrate. It had become conventional wisdom that climate change would follow ozone’s trajectory. Reagan’s E.P.A. administrator, Lee M. Thomas, said as much the day he signed the Montreal Protocol on Substances That Deplete the Ozone Layer (the successor to the Vienna Convention), telling reporters that global warming was likely to be the subject of a future international agreement

Congress had already begun to consider policy — in 1987 alone, there were eight days of climate hearings, in three committees, across both chambers of Congress; Senator Joe Biden, a Delaware Democrat, had introduced legislation to establish a national climate-change strategy. And so it was that Jim Hansen found himself on Oct. 27 in the not especially distinguished ballroom of the Quality Inn on New Jersey Avenue, a block from the Capitol, at “Preparing for Climate Change,” which was technically a conference but felt more like a wedding.

John Topping was an old-line Rockefeller Republican, a Commerce Department lawyer under Nixon and an E.P.A. official under Reagan. He first heard about the climate problem in the halls of the E.P.A. in 1982 and sought out Hansen, who gave him a personal tutorial. Topping was amazed to discover that out of the E.P.A.’s 13,000-person staff, only seven people, by his count, were assigned to work on climate, though he figured it was more important to the long-term security of the nation than every other environmental issue combined.

Glancing around the room, Jim Hansen could chart, like an arborist counting rings on a stump, the growth of the climate issue over the decade. Veterans like Gordon MacDonald, George Woodwell and the environmental biologist Stephen Schneider stood at the center of things. Former and current staff members from the congressional science committees (Tom Grumbly, Curtis Moore, Anthony Scoville) made introductions to the congressmen they advised. Hansen’s owlish nemesis Fred Koomanoff was present, as were his counterparts from the Soviet Union and Western Europe. Rafe Pomerance’s cranium could be seen above the crowd, but unusually he was surrounded by colleagues from other environmental organizations that until now had shown little interest in a diffuse problem with no proven fund-raising record. The party’s most conspicuous newcomers, however, the outermost ring, were the oil-and-gas executives.

That evening, as a storm spat and coughed outside, Rafe Pomerance gave one of his exhortative speeches urging cooperation among the various factions, and John Chafee and Roger Revelle received awards; introductions were made and business cards earnestly exchanged. Not even a presentation by Hansen of his research could sour the mood. The next night, on Oct. 28, at a high-spirited dinner party in Topping’s townhouse on Capitol Hill, the oil-and-gas men joked with the environmentalists, the trade-group representatives chatted up the regulators and the academics got merrily drunk. Mikhail Budyko, the don of the Soviet climatologists, settled into an extended conversation about global warming with Topping’s 10-year-old son. It all seemed like the start of a grand bargain, a uniting of factions — a solution.

Hansen was accustomed to the bureaucratic nuisances that attended testifying before Congress; before a hearing, he had to send his formal statement to NASA headquarters, which forwarded it to the White House’s Office of Management and Budget for approval. “Major greenhouse climate changes are a certainty,” he had written. “By the 2010s [in every scenario], essentially the entire globe has very substantial warming.”

By all appearances, plans for major policy continued to advance rapidly. After the Johnston hearing, Timothy Wirth, a freshman Democratic senator from Colorado on the energy committee, began to plan a comprehensive package of climate-change legislation — a New Deal for global warming. Wirth asked a legislative assistant, David Harwood, to consult with experts on the issue, beginning with Rafe Pomerance, in the hope of converting the science of climate change into a new national energy policy.

In March 1988, Wirth joined 41 other senators, nearly half of them Republicans, to demand that Reagan call for an international treaty modeled after the ozone agreement. Because the United States and the Soviet Union were the world’s two largest contributors of carbon emissions, responsible for about one-third of the world total, they should lead the negotiations. Reagan agreed. In May, he signed a joint statement with Mikhail Gorbachev that included a pledge to cooperate on global warming.

Al Gore himself had, for the moment, withdrawn his political claim to the issue. In 1987, at the age of 39, Gore announced that he was running for president, in part to bring attention to global warming, but he stopped emphasizing it after the subject failed to captivate New Hampshire primary voters.

5. ‘You Will See Things That You Shall Believe’ Summer 1988

It was the hottest and driest summer in history. Everywhere you looked, something was bursting into flames. Two million acres in Alaska incinerated, and dozens of major fires scored the West. Yellowstone National Park lost nearly one million acres. Smoke was visible from Chicago, 1,600 miles away.

In Nebraska, suffering its worst drought since the Dust Bowl, there were days when every weather station registered temperatures above 100 degrees. The director of the Kansas Department of Health and Environment warned that the drought might be the dawning of a climatic change that within a half century could turn the state into a desert.

On June 22 in Washington, where it hit 100 degrees, Rafe Pomerance received a call from Jim Hansen, who was scheduled to testify the following morning at a Senate hearing called by Timothy Wirth. “I hope we have good media coverage tomorrow,” Hansen said.

Hansen had just received the most recent global temperature data. Just over halfway into the year, 1988 was setting records. Already it had nearly clinched the hottest year in history. Ahead of schedule, the signal was emerging from the noise. “I’m going to make a pretty strong statement,” Hansen said.

Hansen returned to his testimony. He wrote: “The global warming is now large enough that we can ascribe with a high degree of confidence a cause-and-effect relationship to the greenhouse effect.” He wrote: “1988 so far is so much warmer than 1987, that barring a remarkable and improbable cooling, 1988 will be the warmest year on record.” He wrote: “The greenhouse effect has been detected, and it is changing our climate now.”

“We have only one planet,” Senator Bennett Johnston intoned. “If we screw it up, we have no place to go.” Senator Max Baucus, a Democrat from Montana, called for the United Nations Environment Program to begin preparing a global remedy to the carbon-dioxide problem. Senator Dale Bumpers, a Democrat of Arkansas, previewed Hansen’s testimony, saying that it “ought to be cause for headlines in every newspaper in America tomorrow morning.” The coverage, Bumpers emphasized, was a necessary precursor to policy. “Nobody wants to take on any of the industries that produce the things that we throw up into the atmosphere,” he said. “But what you have are all these competing interests pitted against our very survival.”

Hansen, wiping his brow, spoke without affect, his eyes rarely rising from his notes. The warming trend could be detected “with 99 percent confidence,” he said. “It is changing our climate now.” But he saved his strongest comment for after the hearing, when he was encircled in the hallway by reporters. “It is time to stop waffling so much,” he said, “and say that the evidence is pretty strong that the greenhouse effect is here.”

The press followed Bumpers’s advice. Hansen’s testimony prompted headlines in dozens of newspapers across the country, including The New York Times, which announced, across the top of its front page: “Global Warming Has Begun, Expert Tells Senate.”

Rafe Pomerance called his allies on Capitol Hill, the young staff members who advised politicians, organized hearings, wrote legislation. We need to finalize a number, he told them, a specific target, in order to move the issue — to turn all this publicity into policy. The Montreal Protocol had called for a 50 percent reduction in CFC emissions by 1998. What was the right target for carbon emissions? It wasn’t enough to exhort nations to do better. That kind of talk might sound noble, but it didn’t change investments or laws. They needed a hard goal — something ambitious but reasonable. And they needed it soon: Just four days after Hansen’s star turn, politicians from 46 nations and more than 300 scientists would convene in Toronto at the World Conference on the Changing Atmosphere, an event described by Philip Shabecoff of The New York Times as “Woodstock for climate change.”

Pomerance had a proposal: a 20 percent reduction in carbon emissions by 2000. Ambitious, Harwood said. In all his work planning climate policy, he had seen no assurance that such a steep drop in emissions was possible. Then again, 2000 was more than a decade off, so it allowed for some flexibility.

Mintzer pointed out that a 20 percent reduction was consistent with the academic literature on energy efficiency. Various studies over the years had shown that you could improve efficiency in most energy systems by roughly 20 percent if you adopted best practices.

Of course, with any target, you had to take into account the fact that the developing world would inevitably consume much larger quantities of fossil fuels by 2000. But those gains could be offset by a wider propagation of the renewable technologies already at hand — solar, wind, geothermal. It was not a rigorous scientific analysis, Mintzer granted, but 20 percent sounded plausible. We wouldn’t need to solve cold fusion or ask Congress to repeal the law of gravity. We could manage it with the knowledge and technology we already had.

Besides, Pomerance said, 20 by 2000 sounds good.

The conference’s final statement, signed by all 400 scientists and politicians in attendance, repeated the demand with a slight variation: a 20 percent reduction in carbon emissions by 2005. Just like that, Pomerance’s best guess became global diplomatic policy.

Hansen, emerging from Anniek’s successful cancer surgery, took it upon himself to start a one-man public information campaign. He gave news conferences and was quoted in seemingly every article about the issue; he even appeared on television with homemade props. Like an entrant at an elementary-school science fair, he made “loaded dice” out of sections of cardboard and colored paper to illustrate the increased likelihood of hotter weather in a warmer climate. Public awareness of the greenhouse effect reached a new high of 68 percent

global warming became a major subject of the presidential campaign. While Michael Dukakis proposed tax incentives to encourage domestic oil production and boasted that coal could satisfy the nation’s energy needs for the next three centuries, George Bush took advantage. “I am an environmentalist,” he declared on the shore of Lake Erie, the first stop on a five-state environmental tour that would take him to Boston Harbor, Dukakis’s home turf. “Those who think we are powerless to do anything about the greenhouse effect,” he said, “are forgetting about the White House effect.”

His running mate emphasized the ticket’s commitment to the issue at the vice-presidential debate. “The greenhouse effect is an important environmental issue,” Dan Quayle said. “We need to get on with it. And in a George Bush administration, you can bet that we will.”

This kind of talk roused the oil-and-gas men. “A lot of people on the Hill see the greenhouse effect as the issue of the 1990s,” a gas lobbyist told Oil & Gas Journal. Before a meeting of oil executives shortly after the “environmentalist” candidate won the election, Representative Dick Cheney, a Wyoming Republican, warned, “It’s going to be very difficult to fend off some kind of gasoline tax.” The coal industry, which had the most to lose from restrictions on carbon emissions, had moved beyond denial to resignation. A spokesman for the National Coal Association acknowledged that the greenhouse effect was no longer “an emerging issue. It is here already, and we’ll be hearing more and more about it.”

By the end of the year, 32 climate bills had been introduced in Congress, led by Wirth’s omnibus National Energy Policy Act of 1988. Co-sponsored by 13 Democrats and five Republicans, it established as a national goal an “International Global Agreement on the Atmosphere by 1992,” ordered the Energy Department to submit to Congress a plan to reduce energy use by at least 2 percent a year through 2005 and directed the Congressional Budget Office to calculate the feasibility of a carbon tax. A lawyer for the Senate energy committee told an industry journal that lawmakers were “frightened” by the issue and predicted that Congress would eventually pass significant legislation after Bush took office

The other great powers refused to wait. The German Parliament created a special commission on climate change, which concluded that action had to be taken immediately, “irrespective of any need for further research,” and that the Toronto goal was inadequate; it recommended a 30 percent reduction of carbon emissions

Margaret Thatcher, who had studied chemistry at Oxford, warned in a speech to the Royal Society that global warming could “greatly exceed the capacity of our natural habitat to cope” and that “the health of the economy and the health of our environment are totally dependent upon each other.”

The prime ministers of Canada and Norway called for a binding international treaty on the atmosphere; Sweden’s Parliament went further, announcing a national strategy to stabilize emissions at the 1988 level and eventually imposing a carbon tax

the United Nations unanimously endorsed the establishment, by the World Meteorological Organization and the United Nations Environment Program, of an Intergovernmental Panel on Climate Change, composed of scientists and policymakers, to conduct scientific assessments and develop global climate policy.

One of the I.P.C.C.’s first sessions to plan an international treaty was hosted by the State Department, 10 days after Bush’s inauguration. James Baker chose the occasion to make his first speech as secretary of state. “We can probably not afford to wait until all of the uncertainties about global climate change have been resolved,” he said. “Time will not make the problem go away.”

: On April 14, 1989, a bipartisan group of 24 senators, led by the majority leader, George Mitchell, requested that Bush cut emissions in the United States even before the I.P.C.C.’s working group made its recommendation. “We cannot afford the long lead times associated with a comprehensive global agreement,” the senators wrote. Bush had promised to combat the greenhouse effect with the White House effect. The self-proclaimed environmentalist was now seated in the Oval Office. It was time.

8. ‘You Never Beat The White House’ April 1989

After Jim Baker gave his boisterous address to the I.P.C.C. working group at the State Department, he received a visit from John Sununu, Bush’s chief of staff. Leave the science to the scientists, Sununu told Baker. Stay clear of this greenhouse-effect nonsense. You don’t know what you’re talking about. Baker, who had served as Reagan’s chief of staff, didn’t speak about the subject again.

despite his reputation as a political wolf, he still thought of himself as a scientist — an “old engineer,” as he was fond of putting it, having earned a Ph.D. in mechanical engineering from M.I.T. decades earlier. He lacked the reflexive deference that so many of his political generation reserved for the class of elite government scientists.

Since World War II, he believed, conspiratorial forces had used the imprimatur of scientific knowledge to advance an “anti-growth” doctrine. He reserved particular disdain for Paul Ehrlich’s “The Population Bomb,” which prophesied that hundreds of millions of people would starve to death if the world took no step to curb population growth; the Club of Rome, an organization of European scientists, heads of state and economists, which similarly warned that the world would run out of natural resources; and as recently as the mid-’70s, the hypothesis advanced by some of the nation’s most celebrated scientists — including Carl Sagan, Stephen Schneider and Ichtiaque Rasool — that a new ice age was dawning, thanks to the proliferation of man-made aerosols. All were theories of questionable scientific merit, portending vast, authoritarian remedies to halt economic progress.

When Mead talked about “far-reaching” decisions and “long-term consequences,” Sununu heard the marching of jackboots.

Sununu had suspected that the greenhouse effect belonged to this nefarious cabal since 1975, when the anthropologist Margaret Mead convened a symposium on the subject at the National Institute of Environmental Health Sciences.

While Sununu and Darman reviewed Hansen’s statements, the E.P.A. administrator, William K. Reilly, took a new proposal to the White House. The next meeting of the I.P.C.C.’s working group was scheduled for Geneva the following month, in May; it was the perfect occasion, Reilly argued, to take a stronger stand on climate change. Bush should demand a global treaty to reduce carbon emissions.

Sununu wouldn’t budge. He ordered the American delegates not to make any commitment in Geneva. Very soon after that, someone leaked the exchange to the press.

A deputy of Jim Baker pulled Reilly aside. He said he had a message from Baker, who had observed Reilly’s infighting with Sununu. “In the long run,” the deputy warned Reilly, “you never beat the White House.”

9. ‘A Form of Science Fraud’ May 1989

The cameras followed Hansen and Gore into the marbled hallway. Hansen insisted that he wanted to focus on the science. Gore focused on the politics. “I think they’re scared of the truth,” he said. “They’re scared that Hansen and the other scientists are right and that some dramatic policy changes are going to be needed, and they don’t want to face up to it.”

The censorship did more to publicize Hansen’s testimony and the dangers of global warming than anything he could have possibly said. At the White House briefing later that morning, Press Secretary Marlin Fitzwater admitted that Hansen’s statement had been changed. He blamed an official “five levels down from the top” and promised that there would be no retaliation. Hansen, he added, was “an outstanding and distinguished scientist” and was “doing a great job.”

10. The White House Effect Fall 1989

The Los Angeles Times called the censorship “an outrageous assault.” The Chicago Tribune said it was the beginning of “a cold war on global warming,” and The New York Times warned that the White House’s “heavy-handed intervention sends the signal that Washington wants to go slow on addressing the greenhouse problem.”

Darman went to see Sununu. He didn’t like being accused of censoring scientists. They needed to issue some kind of response. Sununu called Reilly to ask if he had any ideas. We could start, Reilly said, by recommitting to a global climate treaty. The United States was the only Western nation on record as opposing negotiations.

Sununu sent a telegram to Geneva endorsing a plan “to develop full international consensus on necessary steps to prepare for a formal treaty-negotiating process. The scope and importance of this issue are so great that it is essential for the U.S. to exercise leadership.”

Sununu seethed at any mention of the subject. He had taken it upon himself to study more deeply the greenhouse effect; he would have a rudimentary, one-dimensional general circulation model installed on his personal desktop computer. He decided that the models promoted by Jim Hansen were a lot of bunk. They were horribly imprecise in scale and underestimated the ocean’s ability to mitigate warming. Sununu complained about Hansen to D. Allan Bromley, a nuclear physicist from Yale who, at Sununu’s recommendation, was named Bush’s science adviser. Hansen’s findings were “technical poppycock” that didn’t begin to justify such wild-eyed pronouncements that “the greenhouse effect is here” or that the 1988 heat waves could be attributed to global warming, let alone serve as the basis for national economic policy.

When a junior staff member in the Energy Department, in a meeting at the White House with Sununu and Reilly, mentioned an initiative to reduce fossil-fuel use, Sununu interrupted her. “Why in the world would you need to reduce fossil-fuel use?” he asked. “Because of climate change,” the young woman replied. “I don’t want anyone in this administration without a scientific background using ‘climate change’ or ‘global warming’ ever again,” he said. “If you don’t have a technical basis for policy, don’t run around making decisions on the basis of newspaper headlines.” After the meeting, Reilly caught up to the staff member in the hallway. She was shaken. Don’t take it personally, Reilly told her. Sununu might have been looking at you, but that was directed at me.

Reilly, for his part, didn’t entirely blame Sununu for Bush’s indecision on the prospect of a climate treaty. The president had never taken a vigorous interest in global warming and was mainly briefed about it by nonscientists. Bush had brought up the subject on the campaign trail, in his speech about the White House effect, after leafing through a briefing booklet for a new issue that might generate some positive press. When Reilly tried in person to persuade him to take action, Bush deferred to Sununu and Baker. Why don’t the three of you work it out, he said. Let me know when you decide

Relations between Sununu and Reilly became openly adversarial. Reilly, Sununu thought, was a creature of the environmental lobby. He was trying to impress his friends at the E.P.A. without having a basic grasp of the science himself.

Pomerance had the sinking feeling that the momentum of the previous year was beginning to flag. The censoring of Hansen’s testimony and the inexplicably strident opposition from John Sununu were ominous signs. So were the findings of a report Pomerance had commissioned, published in September by the World Resources Institute, tracking global greenhouse-gas emissions. The United States was the largest contributor by far, producing nearly a quarter of the world’s carbon emissions, and its contribution was growing faster than that of every other country. Bush’s indecision, or perhaps inattention, had already managed to delay the negotiation of a global climate treaty until 1990 at the earliest, perhaps even 1991. By then, Pomerance worried, it would be too late.

Pomerance tried to be more diplomatic. “The president made a commitment to the American people to deal with global warming,” he told The Washington Post, “and he hasn’t followed it up.” He didn’t want to sound defeated. “There are some good building blocks here,” Pomerance said, and he meant it. The Montreal Protocol on CFCs wasn’t perfect at first, either — it had huge loopholes and weak restrictions. Once in place, however, the restrictions could be tightened. Perhaps the same could happen with climate change. Perhaps. Pomerance was not one for pessimism. As William Reilly told reporters, dutifully defending the official position forced upon him, it was the first time that the United States had formally endorsed the concept of an emissions limit. Pomerance wanted to believe that this was progress.

All week in Noordwijk, Becker couldn’t stop talking about what he had seen in Zeeland. After a flood in 1953, when the sea swallowed much of the region, killing more than 2,000 people, the Dutch began to build the Delta Works, a vast concrete-and-steel fortress of movable barriers, dams and sluice gates — a masterpiece of human engineering. The whole system could be locked into place within 90 minutes, defending the land against storm surge. It reduced the country’s exposure to the sea by 700 kilometers, Becker explained. The United States coastline was about 153,000 kilometers long. How long, he asked, was the entire terrestrial coastline? Because the whole world was going to need this. In Zeeland, he said, he had seen the future.

Ken Caldeira, a climate scientist at the Carnegie Institution for Science in Stanford, Calif., has a habit of asking new graduate students to name the largest fundamental breakthrough in climate physics since 1979. It’s a trick question. There has been no breakthrough. As with any mature scientific discipline, there is only refinement. The computer models grow more precise; the regional analyses sharpen; estimates solidify into observational data. Where there have been inaccuracies, they have tended to be in the direction of understatement.

More carbon has been released into the atmosphere since the final day of the Noordwijk conference, Nov. 7, 1989, than in the entire history of civilization preceding it

Despite every action taken since the Charney report — the billions of dollars invested in research, the nonbinding treaties, the investments in renewable energy — the only number that counts, the total quantity of global greenhouse gas emitted per year, has continued its inexorable rise.

When it comes to our own nation, which has failed to make any binding commitments whatsoever, the dominant narrative for the last quarter century has concerned the efforts of the fossil-fuel industries to suppress science, confuse public knowledge and bribe politicians.

The mustache-twirling depravity of these campaigns has left the impression that the oil-and-gas industry always operated thus; while the Exxon scientists and American Petroleum Institute clerics of the ’70s and ’80s were hardly good Samaritans, they did not start multimillion-dollar disinformation campaigns, pay scientists to distort the truth or try to brainwash children in elementary schools, as their successors would.

It was James Hansen’s testimony before Congress in 1988 that, for the first time since the “Changing Climate” report, made oil-and-gas executives begin to consider the issue’s potential to hurt their profits. Exxon, as ever, led the field. Six weeks after Hansen’s testimony, Exxon’s manager of science and strategy development, Duane LeVine, prepared an internal strategy paper urging the company to “emphasize the uncertainty in scientific conclusions.” This shortly became the default position of the entire sector. LeVine, it so happened, served as chairman of the global petroleum industry’s Working Group on Global Climate Change, created the same year, which adopted Exxon’s position as its own

The American Petroleum Institute, after holding a series of internal briefings on the subject in the fall and winter of 1988, including one for the chief executives of the dozen or so largest oil companies, took a similar, if slightly more diplomatic, line. It set aside money for carbon-dioxide policy — about $100,000, a fraction of the millions it was spending on the health effects of benzene, but enough to establish a lobbying organization called, in an admirable flourish of newspeak, the Global Climate Coalition.

The G.C.C. was conceived as a reactive body, to share news of any proposed regulations, but on a whim, it added a press campaign, to be coordinated mainly by the A.P.I. It gave briefings to politicians known to be friendly to the industry and approached scientists who professed skepticism about global warming. The A.P.I.’s payment for an original op-ed was $2,000.

It was joined by the U.S. Chamber of Commerce and 14 other trade associations, including those representing the coal, electric-grid and automobile industries

In October 1989, scientists allied with the G.C.C. began to be quoted in national publications, giving an issue that lacked controversy a convenient fulcrum. “Many respected scientists say the available evidence doesn’t warrant the doomsday warnings,” was the caveat that began to appear in articles on climate change.

The following year, when President Bill Clinton proposed an energy tax in the hope of meeting the goals of the Rio treaty, the A.P.I. invested $1.8 million in a G.C.C. disinformation campaign. Senate Democrats from oil-and-coal states joined Republicans to defeat the tax proposal, which later contributed to the Republicans’ rout of Democrats in the midterm congressional elections in 1994 — the first time the Republican Party had won control of both houses in 40 years

The G.C.C. spent $13 million on a single ad campaign intended to weaken support for the 1997 Kyoto Protocol, which committed its parties to reducing greenhouse-gas emissions by 5 percent relative to 1990 levels. The Senate, which would have had to ratify the agreement, took a pre-emptive vote declaring its opposition; the resolution passed 95-0. There has never been another serious effort to negotiate a binding global climate treaty.

. This has made the corporation an especially vulnerable target for the wave of compensatory litigation that began in earnest in the last three years and may last a generation. Tort lawsuits have become possible only in recent years, as scientists have begun more precisely to attribute regional effects to global emission levels. This is one subfield of climate science that has advanced significantly sin

Pomerance had not been among the 400 delegates invited to Noordwijk. But together with three young activists — Daniel Becker of the Sierra Club, Alden Meyer of the Union of Concerned Scientists and Stewart Boyle from Friends of the Earth — he had formed his own impromptu delegation. Their constituency, they liked to say, was the climate itself. Their mission was to pressure the delegates to include in the final conference statement, which would be used as the basis for a global treaty, the target proposed in Toronto: a 20 percent reduction of greenhouse-gas combustion by 2005. It was the only measure that mattered, the amount of emissions reductions, and the Toronto number was the strongest global target yet proposed.

The delegations would review the progress made by the I.P.C.C. and decide whether to endorse a framework for a global treaty. There was a general sense among the delegates that they would, at minimum, agree to the target proposed by the host, the Dutch environmental minister, more modest than the Toronto number: a freezing of greenhouse-gas emissions at 1990 levels by 2000. Some believed that if the meeting was a success, it would encourage the I.P.C.C. to accelerate its negotiations and reach a decision about a treaty sooner. But at the very least, the world’s environmental ministers should sign a statement endorsing a hard, binding target of emissions reductions. The mood among the delegates was electric, nearly giddy — after more than a decade of fruitless international meetings, they could finally sign an agreement that meant something.

11. ‘The Skunks at The Garden Party’ November 1989

It was nearly freezing — Nov. 6, 1989, on the coast of the North Sea in the Dutch resort town of Noordwijk

Losing Earth: The Decade WeAlmost Stopped Climate Change We knew everything we needed to know, and nothing stood in our way. Nothing, that is, except ourselves. A tragedy in two acts. By Nathaniel RichPhotographs and Videos by George Steinmetz AUG. 1, 2018

“People are beginning to understand that climate change is here in the United States, here in my state, in my community, affecting the people and places I care about, and now,”

Asked whether people in the United States were being harmed by global warming “right now,” 48 percent of the respondents agreed, an increase of nine percentage points since March. And 49 percent said they believed they would be personally harmed by global warming, a seven-point jump over the same period.

he attributed the recent increases to a number of extreme weather events with plausible connections to a warming planet, and to the publicity that surrounded two major scientific reports on climate change last year.

The changes in public opinion over the last year were also tied to politics, Dr. Leiserowitz said, and to the efforts of President Trump to deny the scientific evidence of climate change.

“Every time he talks about climate change he drives more media attention to the exact issue,” Dr. Leiserowitz said

Mr. Trump’s approach to politics is so divisive, Dr. Leiserowitz said, that when he takes a strong stand on climate change and other issues, “he tends to drive a majority of the country in the opposite direction.”

In the poll, a record 62 percent of respondents understood that humans are the main cause of climate change, a four-point rise since March; those attributing it mostly to natural causes were at a record-low 23 percent, a drop of five points over the same period.

She noted that 41 percent of respondents in the poll said they talked about global warming with family and friends “often” or “occasionally,” and 56 percent said they heard about the topic in the news media at least once a month, a 13 percent increase since 2015. “It’s becoming harder and harder to avoid conversations about climate change,” she said.

For the 5.4 million people who live in Russia’s permafrost zone, the new climate has disrupted their homes and their livelihoods. Rivers are rising and running faster, and entire neighborhoods are falling into them. Arable land for farming has plummeted by more than half, to just 120,000 acres in 2017.

As the permafrost thaws, animals and plants frozen for thousands of years begin to decompose and send a steady flow of carbon dioxide and other gases into the atmosphere — accelerating climate change.

Siberians who grew up learning to read nature’s subtlest signals are being driven to migrate by a climate they no longer understand.

This migration from the countryside to cities and towns — also driven by factors such as low investment and spotty Internet — represents one of the most significant and little-noticed movements to date of climate refugees. The city of Yakutsk has seen its population surge 20 percent to more than 300,000 in the past decade.

In Yakutia, an area one-third the size of the United States, cattle and reindeer herding have plunged 20 percent as the animals increasingly battle to survive the warming climate’s destruction of pastureland.

Winters, though still brutal, turned milder — and shorter. Fed by the more rapidly thawing permafrost, rivers started flooding more, leaving some communities inaccessible for months and washing others away, along with the ground beneath them.

a booming cottage industry in mammoth hunting has taken hold

ornithologists in the region have identified 48 new bird species in the past half century, an increase of almost 20 percent in the known diversity of bird life.

“It used to be man was in control,” said Pyotr Kaurgin, head of the Chukchi indigenous community in the village of Kolymskoye, on the northern reaches of the Kolyma River. “Now nature is in control.”

Formed during the late Pleistocene, the Earth’s last glacial period, which ended about 11,700 years ago, Yedoma consists of thick layers of soil packed around gigantic lodes of embedded ice. Because Yedoma contains so much ice, it can melt quickly — reshaping the landscape as sudden lakes form and hillsides collapse.

In the summer, huge blazes tore through Siberian boreal forests, unleashing yet more carbon into the atmosphere. Some scientists fear worsening northern fires are amplifying the permafrost damage.

on the Yamal Peninsula, monstrous craters have opened up in the tundra. Scientists suspect they represent sudden explosions of methane gas freed by thawing permafrost.

Due to thawing permafrost — along with the demise of Soviet-era state farms — the area of cultivated land in Yakutia has plummeted by more than half since 1990. The region’s cattle herds have shrunk by about 20 percent, to 188,100 head in 2017 from 233,300 in 2011. Reindeer herds have also declined sharply

he degradation of crop and pastureland caused by the thawing permafrost helped bring about the collapse of the region’s agriculture.

Yegor Prokopyev, the retired head of Nelemnoye, says climate change is the latest shock to befall the Kolyma River region. There was communism and forced collective farming. Then capitalism and government cutbacks.

. The radical transformation underway here, she said, should serve as a warning to people in every corner of the globe. “Changing our ways is imminent,” Crate said.

The town of Zyryanka has warmed by just over 2 degrees Celsius from 1966 to 2016, according to their analysis.

The Post’s analysis, which uses a data set from Berkeley Earth, looks further back. It shows that Zyryanka and the roughly 2,000-square-mile area surrounding it has warmed by more than 3 degrees Celsius when the past five years are compared with the mid- to late 1800s.

From 2005 to 2014, his team found, the number of days with below-freezing temperatures three feet below the surface fell from around 230 days a year to 190.

enormous wedges of ice lie under Yakutia.

“The permafrost is thawing so fast,” said Anna Liljedahl, an associate professor at the University of Alaska in Fairbanks. “We scientists can’t keep up anymore.”

In the 1970s, Desyatkin said, the ground in the Middle Kolyma District, just north of Zyryanka, thawed to a depth of about two feet every summer. Now it thaws to more than three feet. That extra foot of thawing means that, on average, every square mile of territory has been releasing an additional 700,000 gallons of water into the environment every year

Meanwhile, ancient plant and animal remains trapped inside the Yedoma are exposed to nonfreezing temperatures — or even the open air. That, in turn, activates microbes, which break down the remains and unleash carbon dioxide into the atmosphere, especially from the thawing plant material.

Scientists estimate that the Earth’s Yedoma regions contain between 327 billion and 466 billion tons of carbon. Were it all released into the atmosphere, that would amount to more than half of all human-caused emissions from greenhouse gases and deforestation between 1750 and 2011

As the permafrost thaws and riverbanks erode, more tusks will emerge. Though mammoths disappeared from the Siberian mainland some 10,000 years ago, the government estimates that 500,000 tons of their tusks are still buried in the frozen ground.

Supply and demand are so great that some people are collecting mammoth tusks at near-industrial scale. They use high-pressure hoses to blast away riverbanks and hire teams of young men to comb the wilderness for months at a time.

. In the glutted market, Sivtsev said, the price for top-quality tusks has fallen from about $500 a pound five years ago to around $180.

climate change is leaving people with few choices. “They have to somehow support and feed their families.”

The ducks and geese are just about gone, he said, possibly moving to new habitats in Siberia as the climate shifts. The sable pelts aren’t as thick as they used to be. The shorter winters mean that once reliably frozen-over lakes and rivers are now less predictable, making hunting grounds harder to reach and restricting his ability to get goods to market.

In Nelemnoye, the population has declined to 180 from 210 in the past decade, according to village head Andrei Solntsev. Just 82 of the residents have work. Many factors are pushing people to move to the city — lack of Internet access, poor flight connections, limited job opportunities — but the uncertainty born of a changing climate looms over everything

As the permafrost thaws and recedes, a handful of apartment buildings there are showing signs of structural problems. Sections of many older, wooden buildings already sag toward the ground — rendered uninhabitable by the unevenly thawing earth. New apartment blocks are being built on massive pylons extending ever deeper — more than 40 feet — below ground

a study published this year that the value of buildings and infrastructure on Russian permafrost amounts to $300 billion — about 7.5 percent of the nation’s total annual economic output. They estimate the cost of mitigating the damage wrought by thawing permafrost will probably total more than $100 billion by 2050.

I had other doubts, too. It seemed hubristic, or worse, to make multitrillion-dollar policy bets based on computer models trying to forecast climate patterns decades into the future. Climate activists kept promoting policies based on technologies that were either far from mature (solar energy) or sometimes actively harmful (biofuels).

Expensive efforts to curb greenhouse gas emissions in Europe and North America seemed particularly fruitless when China, India and other developing countries weren’t about to curb their own appetite for fossil fuels

just how fast is Greenland’s ice melting right now? Is this an emergency for our time, or is it a problem for the future?

His pitch was simple: The coastline we have taken for granted for thousands of years of human history changed rapidly in the past on account of natural forces — and would soon be changing rapidly and disastrously by man-made ones. A trip to Greenland, which holds one-eighth of the world’s ice on land (most of the rest is in Antarctica) would show me just how drastic those changes have been. Would I join him?

Greenland is about the size of Alaska and California combined and, except at its coasts, is covered by ice that in places is nearly two miles thick. Even that’s only a fraction of the ice in Antarctica, which is more than six times as large

Greenland’s ice also poses a nearer-term risk because it is melting faster. If all its ice were to melt, global sea levels would rise by some 24 feet. That would be more than enough to inundate hundreds of coastal cities in scores of nations, from Jakarta and Bangkok to Copenhagen and Amsterdam to Miami and New Orleans.

There was also a millenarian fervor that bothered me about climate activism, with its apocalyptic imagery (the Statue of Liberty underwater) and threats of doom unless we were willing to live far more frugally.

“We haven’t had a good positive mass balance year since the late 1990s,” he told me in a follow-on email when I asked him to explain the data for me. The losses can vary sharply by year. The annualized average over the past 30 years, he added, is 170 gigatons per year. That’s the equivalent of about 5,400 tons of ice loss per second. That “suggests that Greenland ice loss has been tracking the I.P.P.C. worse-case, highest-carbon-emission scenario.

The data shows unmistakably that Greenland’s ice is not in balance. It is losing far more than it is gaining.

scientists have been drilling ice-core samples from Greenland for decades, giving them a very good idea of climatic changes stretching back thousands of years. Better yet, a pair of satellites that detect anomalies in Earth’s gravity fields have been taking measurements of the sheet regularly for nearly 20 years, giving scientists a much more precise idea of what is happening.

it’s hard to forecast with any precision what that means. “Anyone who says they know what the sea level is going to be in 2100 is giving you an educated guess,” said NASA’s Willis. “The fact is, we’re seeing these big ice sheets melt for the first time in history, and we don’t really know how fast they can go.”

His own educated guess: “By 2100, we are probably looking at more than a foot or two and hopefully less than seven or eight feet. But we are struggling to figure out just how fast the ice sheets can melt. So the upper end of range is still not well known.”

On the face of it, that sounds manageable. Even if sea levels rise by eight feet, won’t the world have nearly 80 years to come to grips with the problem, during which technologies that help us mitigate the effects of climate change while adapting to its consequences are likely to make dramatic advances?

Won’t the world — including countries that today are poor — become far richer and thus more capable of weathering the floods, surges and superstorms?

The average rate at which sea level is rising around the world, he estimates, has more than tripled over the past three decades, to five millimeters a year from 1.5 millimeters. That may still seem minute, yet as the world learned during the pandemic, exponential increases have a way of hitting hard.

“When something is on a straight line or a smooth curve, you can plot its trajectory,” Englander said. “But sea level, like earthquakes and mudslides, is something that happens irregularly and can change rather quickly and surprise us. The point is, you can no longer predict the future by the recent past.”

In The Wall Street Journal’s editorial pages, where I used to work, the theoretical physicist Steven Koonin, a former under secretary for science in the Obama administration’s Energy Department, cast doubt on the threat from Thwaites in a voice that could have once been mine. He also thinks the risks associated with Greenland’s melting are less a product of human-induced global warming than of natural cycles in North Atlantic currents and temperatures, which over time have a way of regressing to the mean.

Even the poorest countries, while still unacceptably vulnerable, are suffering far fewer human and economic losses to climate-related disasters.

Another climate nonalarmist is Roger Pielke Jr., a professor of environmental studies at the University of Colorado Boulder. I call Pielke a nonalarmist rather than a skeptic because he readily acknowledges that the challenges associated with climate change, including sea-level rise, are real, serious and probably unstoppable, at least for many decades.

“If we have to have a problem,” he told me when I reached him by phone, “we probably want one with a slow onset that we can see coming. It’s not like an asteroid coming from space.”

“Since the 1940s, the impact of floods as a proportion of U.S. gross domestic product has dropped by 70 percent-plus,” Pielke said. “We see this around the world, across phenomena. The story is that fewer people are dying and we are having less damage proportional to G.D.P.”

“Much climate reporting today highlights short-term changes when they fit the narrative of a broken climate but then ignores or plays down changes when they don’t, often dismissing them as ‘just weather,’” he wrote in February.

Global warming is real and getting worse, Pielke said, yet still it’s possible that humanity will be able to adapt to, and compensate for, its effects.

A few years ago, I would have found voices like Koonin’s and Pielke’s persuasive. Now I’m less sure. What intervened was a pandemic.

That’s what I thought until the spring of 2020, when, along with everyone else, I experienced how swiftly and implacably nature can overwhelm even the richest and most technologically advanced societies. It was a lesson in the sort of intellectual humility I recommended for others

It was also a lesson in thinking about risk, especially those in the category known as high-impact, low-probability events that seem to be hitting us with such regularity in this century: the attacks of Sept. 11, 2001; the tsunamis of 2004 and 2011, the mass upheavals in the Arab world

What if the past does nothing to predict the future? What if climate risks do not evolve gradually and relatively predictably but instead suddenly soar uncontrollably? How much lead time is required to deal with something like sea-level rise? How do we weigh the risks of underreacting to climate change against the risks of overreacting to it?

I called Seth Klarman, one of the world’s most successful hedge-fund managers, to think through questions of risk. While he’s not an expert on climate change, he has spent decades thinking deeply about every manner of risk

And we will almost certainly have to do it from sources other than Russia, China, the Democratic Republic of Congo and other places that pose unacceptable strategic, environmental or humanitarian risks

“If you face something that is potentially existential,” he explained, “existential for nations, even for life as we know it, even if you thought the risk is, say, 5 percent, you’d want to hedge against it.”

“One thing we try to do,” he said, “is we buy protection when it’s really inexpensive, even when we think we may well not need it.” The forces contributing to climate change, he noted, echoing Englander, “might be irreversible sooner than the damage from climate change has become fully apparent. You can’t say it’s far off and wait when, if you had acted sooner, you might have dealt with it better and at less cost. We have to act now.”

In other words, an ounce of prevention is worth a pound of cure. That’s particularly true if climate change is akin to cancer — manageable or curable in its earlier stages, disastrous in its later ones.

As I’ve always believed, knowing there is grave risk to future generations — and expecting current ones to make immediate sacrifices for it — defies most of what we know about human nature. So I began to think more deeply about that challenge, and others.

For the world to achieve the net-zero goal for carbon dioxide emissions by 2050, according to the International Energy Agency, we will have to mine, by 2040, six times the current amounts of critical minerals — nickel, cobalt, copper, lithium, manganese, graphite, chromium, rare earths and other minerals and elements — needed for electric vehicles, wind turbines and solar panels.

The poster child for this kind of magical thinking is Germany, which undertook a historic Energiewende — “energy revolution” — only to come up short. At the turn of the century, Germany got about 85 percent of its primary energy from fossil fuels. Now it gets about 78 percent, a puny reduction, considering that the country has spent massive sums on renewables to increase the share of electricity it generates from them.

As in everything else in life, so too with the environment: There is no such thing as a free lunch. Whether it’s nuclear, biofuels, natural gas, hydroelectric or, yes, wind and solar, there will always be serious environmental downsides to any form of energy when used on a massive scale. A single industrial-size wind turbine, for instance, typically requires about a ton of rare earth metals as well as three metric tons of copper, which is notoriously destructive and dirty to mine.

no “clean energy” solution will easily liberate us from our overwhelming and, for now, inescapable dependence on fossil fuels.

Nobody brings the point home better than Vaclav Smil, the Canadian polymath whose most recent book, “How the World Really Works,” should be required reading for policymakers and anyone else interested in a serious discussion about potential climate solutions.

“I’ve talked to so many experts and seen so much evidence,” he told me over Zoom, “I’m convinced the climate is changing, and addressing climate change has become a philanthropic priority of mine.”

Things could turn a corner once scientists finally figure out a technical solution to the energy storage problem. Or when governments and local actors get over their NIMBYism when it comes to permitting and building a large energy grid to move electricity from Germany’s windy north to its energy-hungry south. Or when thoughtful environmental activists finally come to grips with the necessity of nuclear energy

Till then, even as I’ve come to accept the danger we face, I think it’s worth extending the cancer metaphor a little further: Just as cancer treatments, when they work at all, can have terrible side effects, much the same can be said of climate treatments: The gap between an accurate diagnosis and effective treatment remains dismayingly wide

Only when countries like Vietnam and China turned to a different model, of largely bottom-up, market-driven development, did hundreds of millions of people get lifted out of destitution.

the most important transformation has come in agriculture, which uses about 70 percent of the world’s freshwater supply.

Farmers gradually adopted sprinkler and drip irrigation systems, rather than more wasteful flood irrigation, not to conserve water but because the technology provided higher crop yields and larger profit margins.

Water shortages “will spur a revolutionary, aggressive approach to getting rid of flood irrigation,” said Seth Siegel, the chief sustainability officer of the Israeli AgTech company N-Drip. “Most of this innovation will be driven by free-market capitalism, with important incentives from government and NGOs.

meaningful environmental progress has been made through market forces. In this century, America’s carbon dioxide emissions across fuel types have fallen to well below 5,000 million metric tons per year, from a peak of about 6,000 million in 2007, even as our inflation-adjusted G.D.P. has grown by over 50 percent and total population by about 17 percent.

1) Engagement with critics is vital. Insults and stridency are never good tools of persuasion, and trying to cow or censor climate skeptics into silence rarely works

the biggest single driver in emissions reductions from 2005 to 2017 was the switch from coal to natural gas for power generation, since gas produces roughly half the carbon dioxide as coal. This, in turn, was the result of a fracking revolution in the past decade, fiercely resisted by many environmental activists, that made the United States the world’s largest gas producer.

In the long run, we are likelier to make progress when we adopt partial solutions that work with the grain of human nature, not big ones that work against it

Renewables, particularly wind power, played a role. So did efficiency mandates.

The problem with our civilization isn’t overconfidence. It’s polarization, paralysis and a profound lack of trust in all institutions, including the scientific one

Devising effective climate policies begins with recognizing the reality of the social and political landscape in which all policy operates. Some thoughts on how we might do better:

They may not be directly related to climate change but can nonetheless have a positive impact on it. And they probably won’t come in the form of One Big Idea but in thousands of little ones whose cumulative impacts add up.

2) Separate facts from predictions and predictions from policy. Global warming is a fact. So is the human contribution to it. So are observed increases in temperature and sea levels. So are continued increases if we continue to do more of the same. But the rate of those increases is difficult to predict even with the most sophisticated computer modeling

3) Don’t allow climate to become a mainly left-of-center concern. One reason the topic of climate has become so anathema to many conservatives is that so many of the proposed solutions have the flavor, and often the price tag, of old-fashioned statism

4) Be honest about the nature of the challenge. Talk of an imminent climate catastrophe is probably misleading, at least in the way most people understand “imminent.”

A more accurate description of the challenge might be a “potentially imminent tipping point,” meaning the worst consequences of climate change can still be far off but our ability to reverse them is drawing near. Again, the metaphor of cancer — never safe to ignore and always better to deal with at Stage 2 than at Stage 4 — can be helpful.

5) Be humble about the nature of the solutions. The larger the political and financial investment in a “big fix” response to climate change on the scale of the Energiewende, the greater the loss in time, capital and (crucially) public trust when it doesn’t work as planned

6) Begin solving problems our great-grandchildren will face. Start with sea-level rise

We can also stop providing incentives for building in flood-prone areas by raising the price of federal flood insurance to reflect the increased risk more accurately.

7) Stop viewing economic growth as a problem. Industrialization may be the leading cause of climate change. But we cannot and will not reverse it through some form of deindustrialization, which would send the world into poverty and deprivation

8) Get serious about the environmental trade-offs that come with clean energy. You cannot support wind farms but hinder the transmission lines needed to bring their power to the markets where they are needed.

9) A problem for the future is, by its very nature, a moral one. A conservative movement that claims to care about what we owe the future has the twin responsibility of setting an example for its children and at the same time preparing for that future.

He added, “I have a hard time believing that anything they can recommend is going to be a significant factor in population stability or recovery.”

Some policy experts say it can and should survive, with or without the United States.

US officials "stand completely alone on being climate deniers," Jennifer Morgan, executive director of Greenpeace International, told me. "If you look at the speeches from Paris, all the heads of state who came -- all -- and even fossil fuel providers, identified this as a real, science-based issue that they're working to solve together."

Because the Paris Agreement does not levy sanctions or fines against countries that fail to meet their pollution-reduction pledges, it's possible the Trump administration could choose to remain in the agreement while basically polluting as usual.Either tactic -- defection or de facto not caring -- could weaken the pact, potentially leading other nations to defect. The United States, after all, is the second biggest annual climate polluter, after China, and helped negotiate the Paris deal.

By some calculations, we're only five, 10 or perhaps 20-some years away from those red lines if the world keeps polluting at the same staggering rate.

Sterman calculated that the United States pulling out of the Paris Agreement, and canceling many Obama-era climate regulations, including the Clean Power Plan, would increase global temperatures on the order of a few tenths of a degree by 2100. That assumes, however, the rest of the world keeps making aggressive cuts. "Assuming that all nations, including the US, aggressively cut emissions, would yield 1.9 degrees Celsius [of warming] by 2100," he said. "But if the US does nothing, then expected warming rises to 2.2 degrees Celsius by 2100."

Current pledges made as part of the Paris Agreement, including US commitments, put the world at about 3.4 degrees Celsius of warming by 2100, according to Sterman and Climate Interactive. If the entire agreement fell apart and global emissions continued at their current clip, the planet could expect 4.2 degrees of warming.

That could be truly catastrophic. At 6 degrees of warming, for instance, "most of the planetary surface would be functionally uninhabitable," according to Mark Lynas, author of "Six Degrees."

Nearly seven in 10 registered voters in the United States say the country "should participate in the international agreement to curb global warming," according to a November 2016 survey from the Yale Program on Climate Change Communication and the George Mason University Center for Climate Change Communication.

he obtains some consolation by peering into the abyss, entertaining the worst-case scenarios of 6 to 8 degrees Celsius of warming. Given the prospect of utter annihilation, he says, the “degraded muddle” that we might still manage to eke out should count “as an encouraging future.” It would be “merely grim, rather than apocalyptic.”

The overarching frame for Wallace-Wells’s book is an analogous call to action: “How much will we do to stall disaster, and how quickly?”

“The climate system that raised us, and raised everything we now know as human culture and civilization, is now, like a parent, dead,”

“It is about what warming means to the way we live on this planet.” He warns of collapsing ice sheets, water scarcity, an equatorial band too hot to be livable and — for anyone fortunate enough to reside elsewhere — extreme heat waves that will burn longer and kill more. All this could come with 2 degrees Celsius of warming — the threshold that world leaders pledged to stay below in the Paris accords of 2015.

There is no single way to best tell the story of climate change, no single rhetorical approach likely to work on a given audience, and none too dangerous to try,” Wallace-Wells writes. “Any story that sticks is a good one.”

He describes himself as a Bitcoin-buying, non-recycling city-dweller who hates camping. He was scared out of his “fatally complacent, and willfully deluded” inertia when he became immersed in the awful truth and, his book suggests, you can be too

it’s not as if any of the hair-raising material with which he has become intimately familiar has paralyzed him with fatalism — quite the opposite. “That we know global warming is our doing should be a comfort, not a cause for despair,” he writes. What some activists have called “toxic knowledge” — all the intricate feedback loops of societal collapse — “should be empowering.”

even while staring down the bleak decades ahead, Wallace-Wells had a child. “She will watch the world doing battle with a genuinely existential threat,” he writes. “She will be living it — quite literally the greatest story ever told. It may well bring a happy ending.

Mobilization is impossible for people who are sleepwalking their way toward disaster; and mobilization is necessary, he says, to deploy the tools at our disposal, which include carbon taxes, carbon capture and green energy.

His New York magazine article already synthesized plenty of information about perilous climate risks and scared the bejeezus out of people; what are we supposed to do with this expanded litany of horrors?

detail the possible future that awaits the planet should we continue to add carbon to the atmosphere and fail to arrest global warming. Floods, pestilence, famines, wildfires: What he calls the “elements of climate chaos” are veritably biblical in scope

“The Uninhabitable Earth,” David Wallace-Wells

in what could be Mr. Trump’s most consequential action yet, his administration will seek to undermine the very science on which climate change policy rests.

As a result, parts of the federal government will no longer fulfill what scientists say is one of the most urgent jobs of climate science studies: reporting on the future effects of a rapidly warming planet and presenting a picture of what the earth could look like by the end of the century if the global economy continues to emit heat-trapping carbon dioxide pollution from burning fossil fuels.

the White House-appointed director of the United States Geological Survey, James Reilly, a former astronaut and petroleum geologist, has ordered that scientific assessments produced by that office use only computer-generated climate models that project the impact of climate change through 2040, rather than through the end of the century, as had been done previously.

Scientists say that would give a misleading picture because the biggest effects of current emissions will be felt after 2040. Models show that the planet will most likely warm at about the same rate through about 2050. From that point until the end of the century, however, the rate of warming differs significantly with an increase or decrease in carbon emissions.

The administration’s prime target has been the National Climate Assessment, produced by an interagency task force roughly every four years since 2000. Government scientists used computer-generated models in their most recent report to project that if fossil fuel emissions continue unchecked, the earth’s atmosphere could warm by as much as eight degrees Fahrenheit by the end of the century. That would lead to drastically higher sea levels, more devastating storms and droughts, crop failures, food losses and severe health consequences.

“What we have here is a pretty blatant attempt to politicize the science — to push the science in a direction that’s consistent with their politics,” said Philip B. Duffy, the president of the Woods Hole Research Center, who served on a National Academy of Sciences panel that reviewed the government’s most recent National Climate Assessment. “It reminds me of the Soviet Union.”

also to question its conclusions by creating a new climate review panel. That effort is led by a 79-year-old physicist who had a respected career at Princeton but has become better known in recent years for attacking the science of man-made climate change and for defending the virtues of carbon dioxide — sometimes to an awkward degree.

“The demonization of carbon dioxide is just like the demonization of the poor Jews under Hitler,” said the physicist

Mr. Happer and Mr. Bolton are both beneficiaries of Robert and Rebekah Mercer, the far-right billionaire and his daughter who have funded efforts to debunk climate science. The Mercers gave money to a super PAC affiliated with Mr. Bolton before he entered government and to an advocacy group headed by Mr. Happer.

For Mr. Trump, climate change is often the subject of mockery. “Wouldn’t be bad to have a little of that good old fashioned Global Warming right now!” he posted on Twitter in January when a snowstorm was freezing much of the country.

His views are influenced mainly by friends and donors like Carl Icahn, the New York investor who owns oil refineries, and the oil-and-gas billionaire Harold Hamm — both of whom pushed Mr. Trump to deregulate the energy industry.

The president’s advisers amplify his disregard. At the meeting of the eight-nation Arctic Council this month, Secretary of State Mike Pompeo dismayed fellow diplomats by describing the rapidly warming region as a land of “opportunity and abundance” because of its untapped reserves of oil, gas, uranium, gold, fish and rare-earth minerals. The melting sea ice, he said, was opening up new shipping routes.

At the National Security Council, under Mr. Bolton, officials said they had been instructed to strip references to global warming from speeches and other formal statements. But such political edicts pale in significance to the changes in the methodology of scientific reports.

A key change, he said, would be to emphasize historic temperatures rather than models of future atmospheric temperatures, and to eliminate the “worst-case scenarios” of the effect of increased carbon dioxide pollution — sometimes referred to as “business as usual” scenarios because they imply no efforts to curb emissions.

Scientists said that eliminating the worst-case scenario would give a falsely optimistic picture. “Nobody in the world does climate science like that,” said Michael Oppenheimer, a professor of geosciences and international affairs at Princeton. “It would be like designing cars without seatbelts or airbags.”

“It is very unfortunate and potentially even quite damaging that the Trump administration behaves this way,” said Johan Rockström, the director of the Potsdam Institute for Climate Impact Research in Germany. “There is this arrogance and disrespect for scientific advancement — this very demoralizing lack of respect for your own experts and agencies.”

voters may hold him and his administration accountable for brushing aside scientific experts and failing to effectively mobilize the government to minimize natural disasters that have claimed lives, damaged property and threatened economic prosperity.

“Talk to a firefighter if you think that climate change isn’t real,” Mayor Eric M. Garcetti of Los Angeles, a supporter of former Vice President Joseph R. Biden Jr., Mr. Trump’s Democratic opponent, said

“As an historic figure, he is one of the most culpable men in America contributing to the suffering and death that is now occurring through climate-related tragedy,” Jerry Brown, the former California governor

The president’s record is also more consequential, experts say, because the amount of planet-warming carbon dioxide trapped in the Earth’s atmosphere has now passed the point at which scientists say it would be possible to avert many of the worst effects of global warming — even if tough emissions policies are later enacted.

“In both cases, there is no plan to deal with crisis,” he added.

the president has used his time in the nation’s highest office to aggressively promote the burning of fossil fuels, chiefly by rolling back or weakening every major federal policy intended to combat dangerous emissions. At the same time, Mr. Trump and his senior environmental officials have regularly mocked, denied or minimized the established science of human-caused climate change.

At the event in front of supporters in Jupiter, Fla., Mr. Trump declared himself “a great environmentalist.”

The report is clear about the causes — burning fossil fuels — and the effects: It found that the increased drought, flooding, storms and worsening wildfires caused by the warming planet could shrink the American economy by up to 10 percent by the end of the century.

he said of global warming, “I don’t know that it’s man-made,” and suggested that even as the planet warmed, “it will change back again” — an idea scientists have long debunked.

And Mr. Trump’s first appointee to lead the Environmental Protection Agency, Scott Pruitt, declared early in his tenure that carbon dioxide was not a primary contributor to global warming, a statement starkly at odds with the scientific consensus.

He said Mr. Trump had put in place “common sense policies that have kept our air, water and environment clean.”

Taken together, those rules represented the country’s first significant step toward reducing greenhouse gases, while putting the world’s largest economy at the forefront of the global effort to fight climate change.Now they are in shambles.

If Mr. Biden is elected, he has vowed to rejoin the Paris agreement and reinstate those rules, while pushing to enact even stronger policies, spending up to $2 trillion to promote the development of renewable energy sources such as wind and solar.

Taken together, these studies cast doubt on the IPCC's conclusion in 2007 that "the evidence is not sufficient to support a conclusion that [Northern] hemispheric mean temperatures were as warm, or the extent of warm regions as expansive, as those in the 20th century as a whole, during any period in medieval times."

He was referring to warnings that assets worth trillions of dollars are at risk of being stranded, or rendered obsolete, including vast coal and oil deposits that will most likely have to be left in the ground if dangerous levels of global warming are to be prevented.

“I have come to believe that climate change is the existential issue of our age,” Mr. Rubin said. “I believe that investors should insist that companies disclose their risks, including the value of assets that could be stranded.”

“I actually do believe that we’re at a tipping point with the planet,” Mr. Paulson said in an interview at his home in Chicago. “A lot of things are going to happen that none of us are going to like to see.”

The campaign behind the new report, called Risky Business, is funded largely by three wealthy financiers who are strong advocates of action on global warming:

They commissioned an economic modeling firm that often does work for the oil and gas industry, the Rhodium Group, to assemble a team of experts who carried out the risk analysis. Trevor Houser, a Rhodium partner who led the study, sought to insulate the findings from the political opinions of the sponsors, in part by setting up a committee of leading climate scientists and environmental economists who reviewed the work.

Coastal counties, home to 40 percent of the nation’s population, will take especially large hits from the rise of the sea, which could swallow more than $370 billion worth of property in Florida and Louisiana alone by the end of the century.

the global sea level could increase roughly a foot by 2050, and double or triple that by century’s end. A rise of as much as six or eight feet cannot be entirely ruled out, but that is more likely in the next century.

Given that land is sinking in Louisiana even faster than the sea is rising, 4.1 percent to 5.5 percent of all insurable property in that state will be below mean sea level by 2050, the report predicted. By 2100, that figure could reach 15 percent to 20 percent. In Florida, 1 percent to 5 percent of all properties could fall below sea level by 2100, the report said.

the combination of heat and humidity projected for some regions, particularly the Southeast, at century’s end means that anyone working outside at certain times will face a high risk of life-threatening heat stroke.

And in the 22nd century, much of the eastern half of the country could face these conditions for weeks on end, the researchers predicted.

They were able to reverse engineer the ancient climate by analyzing temperature-sensitive structures of lipids produced by fossil bacteria and archaea living in these bygone wetlands, and preserved for all time in the coal. The team found that, under this past regime of high CO2, in the ancient U.K., Germany, and New Zealand, life endured mean annual temperatures of 23–29 degrees Celsius (73–84 degrees Fahrenheit) or 10–15 degrees Celsius (18–27 degrees Fahrenheit) warmer than modern times.

“These wetlands looked exactly how only tropical wetlands look at present, like the Everglades or the Amazon,” Naafs says. “So Europe would look like the Everglades and a heat wave like we’re currently experiencing in Europe would be completely normal. That is, it would be the everyday climate.”

But over 50 million years ago this would have been the baseline from about 45 to 60 degrees latitude. Under this broiling regime, with unprecedented heat as the norm, actual heat waves might have begun to take on an unearthly quality.

closer to the equator in this global sweat lodge, the heat might have been even more outrageous, shattering the limits of complex life. To see exactly how hot, Naafs’ team also analyzed ancient lignite samples from India, which would have been in the tropics at the time—that subcontinent still drifting across the Indian Ocean toward its eventual mountain-raising rendezvous with Asia. But unfortunately, the temperatures from these samples were maxed out. That is, they were too hot for his team to measure by the new methods they had developed.

“Some climate models suggest that the tropics just became a dead zone with temperatures over 50 degrees Celsius (122 degrees Fahrenheit) like in Africa and South America,” says Naafs. “But we have no data so we don’t know.”

“Basically every type of paleoclimate research that’s being done shows that high CO2 means that it’s very warm. And when it gets very warm, it can be really, really, really warm.

“You start really looking into them and you go, ‘Wow. We are dealing with a rainforest.’”

Though there are no trees here at the top of the world, there are tree stumps. And they are around 50 million years old.

One obvious way to reconcile this disparity is by noticing that the changes to the ancient earth took place over hundreds-of-thousands to millions of years and (IPCC graphs notwithstanding) that time won’t stop at the end of the 21st century. The changes that we’ve already set in motion, unless we act rapidly to countervail them, will similarly take millennia to fully unfold

we’re clearly not content to stop at just 400 ppm. If we do, in fact, push CO2 up to around 1,000 ppm by the end of the century, the warming will persist and the earth will continue to change for what, to humans, is a practical eternity

Most worryingly, the climate models that we depend on as a species to predict our future have largely failed to predict our sultry ancient past.

we know methane can actually amplify high-latitude warming, so maybe that’s some of the missing feedback.

“You’ve got alligators, giant tortoises, primates, things like that. We have these big hippo-like animals called Coryphodon. You have tapirs—so you’ve got tapirs living pretty close to the North Pole in the early Eocene, which today—clearly tapirs are not at the North Pole,” she says, laughing.

Clearly we are missing something, and Naafs thinks that one of the missing ingredients in the models is methane, a powerful greenhouse gas which might help close the divide between model worlds and fossil worlds.

We know tropical wetlands pump much more methane into the atmosphere compared to [cooler] wetlands.

The last time CO2 was at 400 ppm (as it is today) was 3 million years ago during the Pliocene epoch, when sea levels were perhaps 80 feet higher than today.

Naafs thinks that many of the wildest features of the early age of mammals could be recreated.

They appeared to miss the so-called global warming hiatus between 1998 and 2013. At the time, scientists posited there wasn’t really a hiatus, but that the heat was simply building up in the oceans, or that there was a data collection issue. They were right, but that didn’t save the models from criticism.

The scientists combined four data sets to paint a picture of what has been happening in the oceans since 1991

Trenberth and his co-authors say ocean heat content, which is a measure of the warmth of the water down to about 2,000 meters, is a “great metric for measuring global warming” because the data isn’t as erratic as the temperature on land, and it captures much more of the planet.

n the process, they discovered something interesting: Their data agrees with what the climate models were predicting

Trenberth and his colleagues say if society continues to emit greenhouse gas at its current rate, oceans will rise one foot by the end of the century on top of the rise expected from melting land ice on Greenland and Antarctica.

This synthesis suggests the models are doing just fine

The IPCC reports have research deadlines at least a year before they are published; science in the most recent report may have been done six to eight years ago and “there’s a whole lot of stuff that has happened since then,”

Looking forward, there are two scenarios scientists are working with. The low-emissions scenario that the Paris climate change agreement was built around is no longer realistic, Trenberth said. The high-emissions, business-as-usual scenario will probably continue until about 2040, in his opinion, but eventually society will figure out how to manage the crisis.

“Yes, we need to try and stop emitting greenhouse gas. But the inertia is large,” Trenberth said. “Therefore the climate is going to continue to change.

Di Liberto agrees that we’re already feeling the effects, but he sees things changing in society, too

“We’ve spent too much time and effort on people who may not be convinced” that climate change is real and important, he said

But now there seems to be this grass-roots movement of young people who care. I don’t remember a time like this.”