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[ two ] THE INCONVENIENT TRUTH Who says climate change is a scientific certainty?

No one, really. Certainties are rare in science. Even the reappearance of the sun over the horizon tomorrow morning can be reduced to a question of probability. On the question of climate change, scientists say they are more than 90 percent sure that it’s happening and that humans are responsible, but you just never know.

Scientists embrace that kind of skepticism. It is through doubting the certainties of the world (the flatness of the Earth, the usefulness of bloodletting) that scientists advance human knowledge. But no serious scientist will stand up and denounce a widely accepted scientific theory without making a verifiable argument to the contrary. Scientists—real scientists—bind themselves to a strict discipline, setting out their theories and experiments carefully, subjecting them to review by other credible scholars who are knowledgeable in their field, and publishing them in reputable journals, such as Science and Nature.

The people who approach the science of climate change with that kind of integrity have agreed on its underlying components for years. The greenhouse effect, by which gases such as carbon dioxide absorb heat, setting up a warming blanket around the world, was first postulated by the French mathematician and physicist Joseph Fourier in 1824. Fourier understood that solar energy heated the Earth, which then reflected that heat back into space in the form of infrared radiation. In effect, the sun’s heat bounced off the Earth’s surface. But Earth’s atmosphere seemed to be blocking or slowing the release of that infrared energy, warming the planet. In the 1850s the Irish physicist John Tyndall figured out a way to actually test and measure the capacity of various gases, including nitrogen, oxygen, water vapour, carbon dioxide, and ozone, to absorb and transmit radiant energy. By 1858 he had effectively proved Fourier’s theory.

At the end of the century—the 19th century—the Swedish scientist Svante Arrhenius advanced the theory even further. Arrhenius, who is considered the founder of physical chemistry, was the first person to predict that humans might actually increase the temperature of the Earth by burning fossil fuels and, in the process, increasing the amount of carbon dioxide in the atmosphere. Fossil fuels themselves represent millions of years of stored carbon. Every living thing on Earth is composed of carbon in one form or another. Plants inhale carbon dioxide, which comprises one molecule of carbon and two of oxygen, then convert the carbon to carbohydrates and release the oxygen back into the atmosphere. Animals eat the plants. Over hundreds of millions of years these plants and animals have fallen dead into swamps or drifted lifeless to the bottom of the ocean, there to be covered up by layers and layers of other carboniferous matter. Under the right conditions—heat and pressure—those massive carbon piles have been converted to coal, oil, or natural gas. And over the last two centuries humans have been digging up those fossil fuels and setting fire to them, reintroducing the carbon to oxygen and releasing the resulting carbon dioxide back into the atmosphere. When Arrhenius considered the effect of this trend, he tried to calculate the effect of that increased carbon dioxide. He estimated that a doubling of atmospheric carbon dioxide would increase Earth’s temperature by 3.8 degrees Fahrenheit. This was a stunning bit of science for the time, given that the most recent report of the Intergovernmental Panel on Climate Change estimates that a doubling of carbon dioxide will increase the global average temperature by between 3.6 and 8.1 degrees Fahrenheit. It’s also unnerving, in that the concentration of carbon dioxide in the atmosphere has risen since 1850 by more than one-third, from 280 parts per million (ppm) to 385 ppm, and we are on track to hit Arrhenius’s feared doubling by sometime near the middle of this century.

The next scientist to ring the climate change alarm was the American oceanographer Roger Revelle, the man who explained the greenhouse effect to former U.S. vice president and Nobel laureate Al Gore when both men were at Harvard in the late 1960s. In 1957 Revelle published a paper with the chemist Hans Suess in which they predicted a global warming. At the time Revelle suggested that such warming might even be a good thing, but he and Suess prescribed caution in their paper, saying that humans were conducting “a great geophysical experiment” with almost no conception of the consequences.

Befitting a society in which scientific understanding guides important social decisions, concern about this issue began to crop up in the political sphere as early as the 1960s. Then-president Lyndon Johnson said in a special message to Congress in February 1965 that “this generation has altered the composition of the atmosphere on a global scale through . . . a steady increase in carbon dioxide from the burning of fossil fuels.”

By the late 1970s scientists were beginning to get twitchy, starting to speak with one increasingly concerned voice. A National Academy of Sciences report authored in 1979 by the scientist Jule Charney said, “A plethora of studies from diverse sources indicates a consensus that climate changes will result from man’s combustion of fossil fuels and changes in land use.” It also was becoming apparent that global warming was not as benign as it sounded. Scientists were beginning to understand that even a small increase in global average temperature could throw off a balance that had existed in Earth’s climate since long before the time of humans. They began warning of melting glaciers and collapsing ice caps, of floods and droughts and rising tides. They began to contemplate a change in world living conditions that was more dramatic than anything in human history and more sudden than anything that had happened in hundreds of thousands of years.

The American political establishment joined the discussion in 1988, led by presidential candidate George H.W. Bush. Running against Democratic contender Michael Dukakis, then-vice president Bush said, “Those who think we are powerless to do anything about the greenhouse effect forget about the ‘White House effect’; as president, I intend to do something about it.” Bush promised, if elected, to convene an international conference on the environment: “We will talk about global warming and we will act.”¹

The newly elected president was, at first, as good as his word. Later the same year, after the world community gathered to create the Intergovernmental Panel on Climate Change (IPCC), Bush signed into law the National Energy Policy Act “to establish a national energy policy that will quickly reduce the generation of carbon dioxide and trace gases as quickly as is feasible in order to slow the pace and degree of atmospheric warming . . . to protect the global environment.”

I offer all of the foregoing for context. I am neither a scientist nor a historian, and I have no intention in this book of jumping into the actual science “debate.” For an in-depth overview, you can go online and read the Fourth Assessment Report of the IPCC, a scientific collaboration of unprecedented breadth, depth, and reputation. You can google Elizabeth Kolbert’s brilliant New Yorker series, The Climate of Man. Or you can pick up one of the great populist science books on the subject: Canadian scientist Andrew Weaver’s Keeping Our Cool; Australian scientist Tim Flannery’s The Weathermakers; Kolbert’s later book Field Notes from a Catastrophe; or Al Gore’s book version of An Inconvenient Truth. Any one of these will give you a solid enough grasp of the science to leave you nervous about the state of our world.

My point, however, is that no one seemed to be confused about climate change in 1988. The great scientific bodies of the world were concerned, and the foremost political leaders were engaged. So what happened between then and now?

Well, here’s what happened in science: with each new experiment, with each new report of the IPCC, with each new article published in legitimate peer-reviewed scientific journals, the science community became more certain that they were on the right track. Naomi Oreskes, a professor of history and science studies at the University of California, San Diego, tested that question in a paper she published in the journal Science in 2005. Oreskes searched the exhaustive ISI Web of Knowledge for refereed scientific journal articles on global climate change that were published between 1993 and 2003, and she analyzed them on the basis of whether they supported, contradicted, or took no position on the consensus that the human release of greenhouse gases was causing climate change. She found 928 articles—and not a single one took exception with the consensus position.

Clear enough. But what was happening in the mainstream media during the same period? The best answer to that question comes from the brothers Jules and Max Boykoff, who published an article in the peer-reviewed Journal of Environmental Change in 2003 titled “Balance as Bias: Global Warming and the U.S. Prestige Press.” The brothers had searched the libraries of four “prestige” dailies in the United States—the New York Times, the Wall Street Journal, the Washington Post, and the Los Angeles Times— and had analyzed their coverage of climate change between 1998 and 2002. They found that while the scientific press was coming down 928 to zero in accepting or, at the very least, not denying climate change, in 53 percent of their stories these four newspapers quoted a scientist on “one side” of the issue and a spokesperson on the other. I say spokesperson rather than scientist for two reasons. First, the deniers were very often not scientists, but rather political ideologues or self-appointed “experts” from think tanks. Second, even when the experts had scientific credentials, in most cases those credentials were not relevant to the topic at hand. The experts were geologists or economists commenting outside their field of expertise, not climate scientists reporting on up-to-date peer-reviewed science.

Boykoff and Boykoff telegraphed their point about the mainstream media in the title of their paper “Balance as Bias.” Journalists in the modern age find it all but impossible to stay up to speed on every issue, especially every issue of science. To protect themselves, they very frequently fall back on the notion of balance: they interview one person on one side of an issue and one person on the other. There is even a fairly common conceit in North American newsrooms that if both sides wind up angry about the coverage, the reporter in question probably got the story about right.

This has a degree of legitimacy when the subject matter is political, economic, or even moral. There are legitimate differences of opinion on the correct way to handle many political issues, and few economists agree on the right response to a specific economic event. And on a highly emotional issue such as abortion—one in which people are just as likely to be bringing forth points that are based in religion as they are to be talking about science—it is completely appropriate to canvas a range of opinions.

But science is a discipline in which there are legitimate subject experts, people whose knowledge is weighed and measured by their scientific peers. This is the process people use to decide, for example, on a new surgical method or on the structural strength of a new metal alloy. If a doctor recommended that you undergo an innovative new surgical procedure, you might seek a second opinion, but you’d probably ask another surgeon. You wouldn’t check with your local carpenter, and you certainly wouldn’t ask a representative of the drug company whose product would be rendered irrelevant if you had the operation. If you were building an apartment block or a bridge and someone offered a “state-of-the-art” new girder that was lighter and cheaper than the conventional alternative, you wouldn’t accept the recommendation on the basis of the salesman’s promises or even on the latest feature in Reader’s Digest. You would insist on a testimonial from scientific sources.

That’s not what’s been happening in the public conversation about global warming. For most of the last two decades, while scientists were growing more convinced about the proof and more concerned about the risks of climate change, members of the general public were drifting into confusion, led there by conflicting stories that minimized the state of the problem and exaggerated the cost of solutions. Somehow, we have been spun.