Little of this process was evident to the public or even other researchers. Climate science was a new field that relied on gigantic computer simulations of a sort unfamiliar outside the climate community. Often its practitioners had drifted into climate from other disciplines and worked not in traditional universities but at specialized institutions—Scripps, for instance, or the Joint Numerical Weather Prediction Unit (a collaboration of the Pentagon and the U.S. Weather Bureau that was disbanded in 1960)—with only loose connections to the rest of academia. Later these stand-alone climate centers appeared all over the world, including the Center for International Climate and Environmental Research in Oslo, the Wuppertal Institute for Climate, Environment, and Energy in western Germany, and the National Center for Atmospheric Research, the government-funded Colorado research organization that hosted “The Causes of Climate Change.” For their part, more than a few university scientists regarded climatologists as Johnny-come-latelies who exaggerated their importance to snatch more funding for their jet-setting international conferences and glittering laboratory centers (the National Center for Atmospheric Research headquarters was designed by the star architect I. M. Pei). And they scoffed at how few climatological theories seemed to be testable in traditional scientific experiments. Climatologists retorted that a second Earth isn’t available for testing climate theories. Instead, they were forced to refine ever more complex mathematical models, which grew ever harder for outsiders to understand. Later, as ever bolder claims about the effects of global warming issued from climate centers, some university-bound economists, ecologists, sociologists, and historians charged that the centers, stocked mainly with physical scientists, ignored or misrepresented the economic, social, ecological, and historical aspects of the subject, leading to a new version of the old environmental determinism.
Adding to the confusion, some climate scientists were warning of global cooling. In 1963 Reid Bryson, founding head of the University of Wisconsin meteorology department, flew to India. As the plane neared its destination he was surprised to see that smoke and dust entirely blocked his view below. The smoke came from farmers burning fields, the dust from wind blowing over drought-stricken ground. Adding to the soup was coal smoke from India’s new factories. Bryson knew that microscopic particles of smoke, soot, smog, and dust—“aerosols,” in the jargon—should scatter the sun’s rays before they hit the surface. An obvious question: Could this affect the climate? At a 1968 symposium Bryson and others suggested that aerosols from human activity might cool Earth faster than carbon dioxide could heat it. Carbon dioxide researchers disagreed. In typical fashion, cooling and warming advocates split into two factions, each regarding the other as misguided.
Two scientists at the National Aeronautics and Space Administration, S. Ichtiaque Rasool and Stephen H. Schneider, tried to resolve the conflict by adding aerosols into the models used for carbon dioxide. A third NASA researcher, James E. Hansen, had developed a model to study the cloudbanks of Venus. Rasool and Schneider adapted Hansen’s model to examine the smogbanks of Earth. In 1971 they published their conclusion in the journal Science: doubling atmospheric carbon dioxide levels would have little impact, but a sustained air-pollution increase would “trigger an ice age.” Rasool went further in The Washington Post. If pollution kept increasing, he told a startled reporter, the next ice age could arrive in “five to ten” years—the glaciers would begin growing by 1981.
Coming as the environmental movement rose into public view, the image of humanity literally blocking the sun with its filth was apocalyptic yet accessible—and, for the next few years, irresistible. “Brace Yourself for Another Ice Age,” advised Science Digest. “What’s Happening to Our Climate?” asked National Geographic; it quoted two scientists warning that if pollution didn’t stop, “continental snow cover would soon advance to the Equator.” Newsweek invoked “A Cooling World.” The futurist Lowell Ponte published The Cooling (1976), which predicted that freezing temperatures would destroy the Soviet grain harvest, setting off World War III. “There will be megadeaths,” intoned George F. Will in The Washington Post, as he described projections of a global drop of “two or three degrees by the end of the century.”
Will based his megadeaths story on a 1974 Central Intelligence Agency report about trends in population, food, and climate. The report stressed that climate-change discussions were “highly speculative” and that “experts will disagree with some or many of the implicit assumptions.” Nonetheless, it provided the views of only one expert: Reid Bryson, global cooling’s progenitor. So firmly did Bryson embrace cooling that he evidently neglected to tell the CIA about the other side of the debate. Like a lazy journalist, the CIA based its story on a single source. Altogether, seventy-one scientific papers devoted to the cooling/warming debate appeared between 1965 and 1979. Seven favored cooling, twenty were neutral, and forty-four argued for warming. Bryson, the CIA source, belonged to a vocal minority.
Among the warming advocates was NASA’s Schneider, who had reversed his initial assessment. As a simplifying assumption, the computer model he borrowed from Hansen had treated the atmosphere as a single uniform air mass. Instead we know it to be a stack of layers, each with different characteristics: troposphere (from the surface to about ten miles up), stratosphere (from the troposphere to about thirty miles up), mesosphere (from the stratosphere to about ninety miles up), and so on. The stratosphere holds a lower level of water vapor than the troposphere, but roughly the same level of carbon dioxide. When Schneider incorporated atmospheric layers into the model, the output changed. Now the carbon dioxide in the stratosphere trapped an appreciable part of the infrared light from the surface that made it through the troposphere and beamed it back to the ground, amplifying the warming. By 1974 Schneider was suggesting that “a reasonable first-order estimate” for the effect of doubling carbon dioxide levels would be a rise of 3.6°F—a big change from his first answer.
For many politicians, NASA researcher James Hansen’s 1988 Senate testimony that a minute additional percentage of carbon dioxide in the air was “changing our climate now” was their first, startling encounter with an issue that over the years would grow ever more contentious. Credit 71
Even as Schneider and others homed in on carbon dioxide, Hansen and two NASA colleagues were examining the other side: aerosols. Using a similar model, the three men tested its predictions against the results of an actual volcano: the 1963 eruption of Mount Agung in Bali, which killed more than a thousand people and shot enough junk into the air to have a measurable effect on the climate. The predictions of the model matched events closely enough that Hansen and his colleagues were able to sort out the relative contributions of aerosol cooling and carbon dioxide warming.
Comparing the impact of cooling (sharp, sudden bursts) to that of warming (slow and steady), Hansen and most other climate scientists became convinced that in standard Aesopian fashion tortoise would beat hare: warming would predominate in the long run. Not all climate scientists were persuaded—Reid Bryson, for one, went to his grave in 2008 awaiting the onset of glaciation—but the great majority were. Increasingly, research centers and government panels beat the drum for warming.
Despite their efforts, climate change attracted little public notice until June 23, 1988, when Hansen testified before the U.S. Senate. Worried about climate change, Colorado Democratic senator Tim Wirth had deliberately scheduled the hearing for what historically was the city summer’s hottest day. His scheme worked beyond his wildest dreams. Hansen sat down amid a wave of bad weather that covered the entire planet. Downpours inundated parts of Africa; unseasonable cold shriveled European harvests. Droughts scorched crops in the U.S. Midwest; forests were aflame across the West. That day Washington, D.C., experienced a record 101°F—an effect amplified when Wirth shut off the air-conditioning in the hearing room. Adding to the heat was the glare from television lights. Perspiration glistened on Hansen’s temples as he spoke. He said, “Earth is warmer in 1988 than in any time
in the history of instrumental measurements.” He said, “With 99 percent confidence we can state that the warming during this time period is a real warming trend.” Carbon dioxide, he said, “is changing our climate now.”
Hansen’s stark words were headline news across the world. The New York Times put his charts on page one, and he appeared on a dozen television shows. “Changing our climate now” transformed parched fields, overflowing rivers, and sweltering cities from a random cluster of bad weather into a harbinger of a dystopian future. Adding to the furor, the journalist Bill McKibben published in 1989 the first popular account of climate change, The End of Nature, a worldwide best seller despite its ominous title. More important, scientific research took off. Before 1988 peer-reviewed journals had never published more than a score of articles in a given year that contained the terms “climate change” or “global warming.” After 1988 the figure climbed: 55 in 1989; 138 in 1990; 348 in 1991. By 2000: 1,340. In 2015 it was 16,576.
By happenstance, the World Conference on the Changing Atmosphere began four days after Hansen spoke. Held in Toronto, it was the first major international gathering of scientists and politicians dedicated to global warming. Reporters primed by Hansen’s testimony descended upon the attendees. They heard the conference issue a statement that called for reducing carbon dioxide emissions by 20 percent by 2005. They heard respectable politicians insisting that “it is imperative to act now.” They heard, they wrote, they published. More headlines, more editorials, more predictions of doom, more calls for action.
Nonetheless, many non-climatologists—physicists, economists, politicians, geologists, even meteorologists—remained skeptical. To climatologists like Hansen, his statement felt like the culmination of 150 years of scientific debate that had in the end led to a high degree of certainty. To politicians, his ideas seemed to come out of nowhere. The notion that a colorless, odorless, nontoxic gas that formed less than 1 percent of the atmosphere might threaten civilization decades from now was so bewildering—as vague and abstract as it was vast—that they instinctively recoiled. Naturally, they sought a way to categorize it. They viewed it as the latest environmental crusade about the air.
Uncivil, Uncertain
Here, at last, we join the second approach to thinking about climate change: how political institutions have grappled with it. In a sense, the answer is simple: they have viewed it as a kind of logical culmination of the environmental movement. Which is to say that it became the heir of an entire history—Vogt’s history, in part.
By the late 1960s, when the modern environmental movement took off, most of the left and right agreed, however uneasily, on the need to curb pollution. Two years after winning the divisive 1968 election, President Richard Nixon, a Republican, declared that “the environment,” “the great question of the ’70s,” was a “cause beyond party and beyond factions.” The Clean Air Act of that year, which set up U.S. emissions regulations, was one of the world’s first general air-quality laws, more stringent and comprehensive than any of its predecessors. Congress passed it overwhelmingly: 73–0 in the Senate, 374–1 in the House of Representatives. Business generally endorsed the legislation; the smog blanketing U.S. cities was obviously harmful and obviously in need of control. Such was the consensus that the distinguished sociologist David L. Sills could observe in 1975 that the new environmental movement “contains all shades of political opinion from the conservative right to the radical left.” With little dissent, Washington passed twenty-one major environmental bills, one after another, in the 1970s.
Soon, though, business interests realized that these rules were just the beginning. Dirty air was succeeded by new alarms about the atmosphere, one after another. The ozone hole. Nuclear winter. Acid rain.*8 Each was more abstract than its predecessor but larger in immediate economic impact. Industry, sensing a trend, became wary. What had begun as a feel-good movement against a limited tally of palpable local harms seemed to have become an endless crusade against ever-larger and ever-remoter targets. A stream of “capitalism vs. ecology” manifestos led many in the business world to conclude that destroying the corporate world had been the aim from the beginning. Ranchers, farmers, loggers, and miners, touched by environmental laws, came to the same conclusion: a cabal of urban snobs was bent on destroying their livelihoods. Increasingly, they resisted. Reflexively, the anti-corporate left doubled down.
The result was a dance that became ever more dysfunctional, as the Emory University historian Patrick Allitt wrote in A Climate of Crisis (2014), his history of the environmental movement. Time and again, activists and corporate executives railed against each other. Time and again, regulatory syntheses emerged from this clash: rules for air, water, toxins. Often enough, businesspeople discovered that the new regulation was less costly than they had feared; environmentalists, meanwhile, found out that the problem was less dire than they had feared.
Rather than concluding from this history that, as Allitt put it, “environmental problems, though very real, were manageable,” each side stored up bitterness, like batteries taking on charge. The process that had led, often disagreeably, to successful environmental action in the 1970s brought on political stasis by the 1990s. Environmental issues became ways for politicians to flag their clan identity to supporters—less statements about practical problems with solutions that people could debate than symbols of identity. They signaled membership in a cause: taking back the country, either from tyrannical liberal elitism or right-wing greed.
To the growing anti-green opposition, climate change seemed like the logical extension of a long-brewing battle. Given the history, this may have been inevitable. The chain of reactions that leads from tailpipe emissions to climate change is not easy to visualize. To most people in the world, it remains an abstract peril, encountered mainly in the form of news reports about droughts and floods in faraway places or scientific studies filled with charts and graphs.
Even to scientists, climate change can be as hard to nail down as a blob of mercury. Arrhenius tried to figure out what would happen to global average temperatures if atmospheric carbon dioxide levels doubled, a measure of what today is known as “climate sensitivity.” Before the widespread use of fossil fuels—before 1880, more or less—the atmospheric carbon dioxide level was about 280 parts per million. Arrhenius in effect asked what would happen if that number went up to 560 parts per million. In 1979 the U.S. National Research Council asked the same question. Its report projected that doubling atmospheric carbon dioxide would raise global temperatures by between 2.7°F and 8.1°F (1.5°C and 4.5°C). The National Research Council team had produced its estimate by averaging the results from two models and adding about 1°F on either end to account for uncertainty. The procedure—crude, but the best available at the time—was not enough to convince the Carter administration to stop boosting coal production. Since then, many other scientific groups have tried to improve climate-sensitivity estimates. Notable among them was the Intergovernmental Panel on Climate Change, which has produced five major reports on the state of climate science, the most recent in 2014. All five attempted to assess climate sensitivity. Unfortunately, as the economists Gernot Wagner and Martin L. Weitzman lament in their book Climate Shock (2015), the likely range of increase from doubling carbon dioxide levels foreseen in the last IPCC report—2.7°–8.1°F (1.5–4.5°C)—was exactly what it was in 1979. Four decades of additional research has not brought us closer to predicting the precise impact of dumping carbon dioxide into the air.
This is not because the researchers are lazy or incompetent. It is because global climate is a phenomenally complex problem: a system with multiple interacting parts, of which many, as Lorenz showed, can be sweepingly affected by tiny changes. Still, the uncertainty puts political leaders in a bind. A rise of 2.7°F would be tolerable, it is generally believed, whereas a rise of 8.1°F would be intolerable: enough to melt the polar ice, inundating coastlines around the world. The estimates of climate sensitivity were like announcing to poli
ticians that something truly awful might happen—or might not. It is as if our species were running blindfolded toward a cliff. Nobody knows the cliff’s precise location or height. There is a small chance that it is so low and far away as to be harmless—and a larger chance that it is high and rapidly approaching.
If the problem was nebulous, the general solution was clear. Hansen did not utter the terms “fossil fuels” or “petroleum” in his 1988 testimony. Nonetheless, everyone in the room understood that the climate change he described could not be addressed without taking on, as Arkansas Democratic senator Dale Bumpers put it at the hearing, “the industries that produce the things that we throw up into the atmosphere.” It would require vast changes in the energy business, one of the most important sectors of the world economy, and probably its most politically powerful. And these changes—unlike those required for endangered species or the ozone hole—would reach into the lives of almost everyone on Earth.
Thinking about the implications, Bumpers’s colleague, Senator Pete Domenici, Republican from New Mexico, recoiled. Nobody, he told the hearing, will “move in areas such as this until we either have a disaster or we have absolute concrete proof. And even when we have that, it seems that we need a game plan of some type.” And he asked the panel, “Have any of you put forth a concrete proposal which I assume would involve both further investigations and a course of action?”