In the United States the first high-level government mention of global warming was buried deep within a 1965 White House report on the nation’s environmental problems. Throughout the 1960s and 1970s global warming—at that time typically referred to as “inadvertent modification of the atmosphere,” and today embraced by the term “climate change”—remained an intriguing hypothesis that caught the attention of a few scientists but generated little concern among the public or environmentalists. Indeed, some climate researchers saw evidence for global cooling and a future ice age. In any case, the threat of nuclear war was sufficiently urgent, plausible, and horrific to crowd global warming off the catastrophe agenda.
Continued research, however, fortified the theory that fossil-fuel combustion could contribute to global warming. In 1977 the nonpartisan National Academy of Sciences issued a study called Energy and Climate, which carefully suggested that the possibility of global warming “should lead neither to panic nor to complacency.” Rather, the study continued, it should “engender a lively sense of urgency in getting on with the work of illuminating the issues that have been identified and resolving the scientific uncertainties that remain.” As is typical with National Academy studies, the primary recommendation was for more research. [an error occurred while processing this directive] In the early 1980s the carbon-dioxide problem received its first sustained attention in Congress, in the form of hearings organized by Representative Al Gore, who had become concerned about global warming when he took a college course with Roger Revelle, twelve years earlier. In 1983 the Environmental Protection Agency released a report detailing some of the possible threats posed by the anthropogenic, or human-caused, emission of carbon dioxide, but the Reagan Administration decisively downplayed the document. Two years later a prestigious international scientific conference in Villach, Austria, concluded that climate change deserved the attention of policymakers worldwide. The following year, at a Senate fact-finding hearing stimulated by the conference, Robert Watson, a climate scientist at NASA, testified, “Global warming is inevitable. It is only a question of the magnitude and the timing.”
At that point global warming was only beginning to insinuate itself into the public consciousness. The defining event came in June of 1988, when another NASA climate scientist, James Hansen, told Congress with “ninety-nine percent confidence” that “the greenhouse effect has been detected, and it is changing our climate now.” Hansen’s proclamation made the front pages of major newspapers, ignited a firestorm of public debate, and elevated the carbon-dioxide problem to pre-eminence on the environmental agenda, where it remains to this day. Nothing had so galvanized the environmental community since the original Earth Day, eighteen years before.
Historically, the conservation and environmental movements have been rooted in values that celebrate the intrinsic worth of unspoiled landscape and propagate the idea that the human spirit is sustained through communion with nature. More than fifty years ago Aldo Leopold, perhaps the most important environmental voice of the twentieth century, wrote, “We face the question whether a still higher ’standard of living’ is worth its cost in things natural, wild, and free. For us of the minority, ... the chance to find a pasque-flower is a right as inalienable as free speech.” But when global warming appeared, environmentalists thought they had found a justification better than inalienable rights—they had found facts and rationality, and they fell head over heels in love with science.
Of course, modern environmentalists were already in the habit of calling on science to help advance their agenda. In 1967, for example, the Environmental Defense Fund was founded with the aim of using science to support environmental protection through litigation. But global warming was, and is, different. It exists as an environmental issue only because of science. People can’t directly sense global warming, the way they can see a clear-cut forest or feel the sting of urban smog in their throats. It is not a discrete event, like an oil spill or a nuclear accident. Global warming is so abstract that scientists argue over how they would know if they actually observed it. Scientists go to great lengths to measure and derive something called the “global average temperature” at the earth’s surface, and the total rise in this temperature over the past century—an increase of about six tenths of a degree Celsius as of 1998—does suggest warming. But people and ecosystems experience local and regional temperatures, not the global average. Furthermore, most of the possible effects of global warming are not apparent in the present; rather, scientists predict that they will occur decades or even centuries hence. Nor is it likely that scientists will ever be able to attribute any isolated event—a hurricane, a heat wave—to global warming.
A central tenet of environmentalism is that less human interference in nature is better than more. The imagination of the environmental community was ignited not by the observation that greenhouse-gas concentrations were increasing but by the scientific conclusion that the increase was caused by human beings. The Environmental Defense Fund, perhaps because of its explicitly scientific bent, was one of the first advocacy groups to make this connection. As early as 1984 its senior scientist, Michael Oppenheimer, wrote on the op-ed page of The New York Times,
With unusual unanimity, scientists testified at a recent Senate hearing that using the atmosphere as a garbage dump is about to catch up with us on a global scale.... Carbon dioxide emissions from fossil fuel combustion and other “greenhouse” gases are throwing a blanket over the Earth.... The sea level will rise as land ice melts and the ocean expands. Beaches will erode while wetlands will largely disappear.... Imagine life in a sweltering, smoggy New York without Long Island’s beaches and you have glimpsed the world left to future generations.
Preserving tropical jungles and wetlands, protecting air and water quality, slowing global population growth—goals that had all been justified for independent reasons, often by independent organizations—could now be linked to a single fact, anthropogenic carbon-dioxide emissions, and advanced along a single political front, the effort to reduce those emissions. Protecting forests, for example, could help fight global warming because forests act as “sinks” that absorb carbon dioxide. Air pollution could be addressed in part by promoting the same clean-energy sources that would reduce carbon-dioxide emissions. Population growth needed to be controlled in order to reduce demand for fossil-fuel combustion. And the environmental community could reinvigorate its energy-conservation agenda, which had flagged since the early 1980s, when the effects of the second Arab oil shock wore off. Senator Timothy Wirth, of Colorado, spelled out the strategy in 1988: “What we’ve got to do in energy conservation is try to ride the global warming issue. Even if the theory of global warming is wrong, to have approached global warming as if it is real means energy conservation, so we will be doing the right thing anyway in terms of economic policy and environmental policy.” A broad array of environmental groups and think tanks, including the Environmental Defense Fund, the Sierra Club, Greenpeace, the World Resources Institute, and the Union of Concerned Scientists, made reductions in carbon-dioxide emissions central to their agendas.
The moral problem seemed clear: human beings were causing the increase of carbon dioxide in the atmosphere. But the moral problem existed only because of a scientific fact—a fact that not only provided justification for doing many of the things that environmentalists wanted to do anyway but also dictated the overriding course of action: reduce carbon-dioxide emissions. Thus science was used to rationalize the moral imperative, unify the environmental agenda, and determine the political solution.