As president emeritus of Stanford University, former commissioner of the Food and Drug Administration, and current editor-in-chief of Science magazine, Donald Kennedy is a hard scientist to ignore. And now he’s shouting from the battlements a resounding message: “Get ready for global warming.” On June 15, Kennedy hosted a star-studded conference on climate change at the American Association for the Advancement of Science (AAAS) in Washington, D.C., an all day event clearly designed to put the issue squarely on the public agenda. The assembled speakers powerfully argued that, despite a continuing gap between alarmed scientists and a yawning public, we would be foolish to ignore global warming—despite the siren calls of so-called “skeptics” who continue to dispute mainstream conclusions on this issue.
At the AAAS event, Kennedy pointed to a “growing dissatisfaction” among scientists that the consensus they’ve reached on human-caused, or anthropogenic, global warming has been so poorly communicated to the public at large. While fully admitting that questions remain about the way climate change will affect our future, Kennedy nevertheless argued that none of these uncertainties constitute “an argument for waiting,” given the severity of the possible consequences. “It really is time to get some serious policy traction on this issue,” he declared.
Kennedy’s call to action drew strength from the impressive cast of speakers who preceded him. Drawing on a wide range of evidence, these scientists convincingly demonstrated that human induced climate change has already begun. First, F. Sherwood Rowland, who won the Nobel Prize in chemistry for his work on the role of CFCs in causing ozone depletion, explained that the greenhouse effect—in which atmospheric gases like carbon dioxide trap the earth’s heat and prevent it from escaping—is “a very well established scientific principle.” And it provides firm grounds for concern: Atmospheric carbon dioxide levels have been steadily rising thanks to fossil fuel emissions, and now stand at 380 parts per million (ppm). Meanwhile, we’ve witnessed a one degree Fahrenheit rise in global temperatures between the early 1800s and the present, with most of the change occurring in the past decade.
Putting that 380 parts per million figure in context, a later speaker—Harvard geochemist Dan Schrag—pointed out that carbon dioxide levels have not exceeded 300 ppm for the last 400,000 years. And by 2040 or 2060, he added, it’s projected that we’ll reach 500 ppm! Comparing where we’re headed to the sultry Eocene epoch many millions of years ago—when palm trees grew in Wyoming and crocodiles lived in the Arctic—Schrag concluded, “We’re performing an experiment at a planetary scale that hasn’t been done for millions of years.”
Drawing further upon paleoclimatology, other scientists argued that recent warming has been occurring faster “than anything we’ve seen in earth history,” as Duke’s Thomas Crowley put it. To bolster this contention, Crowley showed how a range of different proxy data—derived from tree rings, ice cores, and coral reefs—all independently confirm the anomalous nature of recent warming when viewed in the context of the past thousand years.
Later presenters then went on to highlight the evidence of climate change that surrounds us today. Sea levels are rising, noted Princeton’s Michael Oppenheimer, and polar ice sheets appear vulnerable to significant future melting. Mountain glaciers worldwide are retreating, added Ohio State’s Lonnie Thompson. “Within thirty years there will be no ice in Glacier National Park,” he predicted. Meanwhile, a wide range of species are adjusting their habitat ranges in response to temperature shifts, noted Chris Field of the Carnegie Institution—sometimes at rates of up to several miles per decade.
Perhaps most troublingly, the scientists concurred that current climate models may underestimate the magnitude, as well as the rapidity, of coming changes. “The real world never changes smoothly, it always bumps and jumps and wiggles,” said geoscientist Richard Alley of Penn State University. In other words, in the future we should expect the unexpected from the climate. Uncertainty about what may happen therefore hardly constitutes a cause for inaction; on the contrary, it should be deeply worrisome.
Granted, none of the so-called climate change “skeptics”—Fred Singer of the Science and Environmental Policy Project, the Cato Institute’s Patrick Michaels, and various others—presented their views at this event. It’s a safe bet that they would have disagreed with much of what was said, probably quibbling over every last detail. Certainly they would argue that the AAAS and Kennedy are presenting a highly skewed perspective on a complex and contentious issue. In fact, they’ve done precisely that in the past.
But before you embrace that conclusion, just consider: Few of these “skeptics” have been publishing very much lately in the peer reviewed scientific literature. A global consensus has formed on climate change despite their finest efforts to derail it, and has in turn been confirmed by both the U.S. National Academy of Sciences and the United Nations’ Intergovernmental Panel on Climate Change (IPCC). “Consensus as strong as the one that has developed around this topic is rare in science,” Kennedy has noted.
Why does this matter? Well, the scientists whose views I detailed above fit firmly into the mainstream and were presenting consensus positions, not controversial ones. It would be a stretch to say that the theory of anthropogenic climate change has become as firmly established as, say, the theory of evolution, but there are telling similarities. Both views have won broad acceptance by the vast majority of scientific experts, and now only come under fire from a small band of contrarian outliers. Moreover, the outliers aren’t contributing much real science at this point. With a few exceptions, they’re taking their case straight to journalists and public policymakers, an end run around the peer review process. And of course, when the debate isn’t going their way, they cry persecution.
Skeptics should recognize many of these traits: We’ve seen them before not just in anti-evolutionists but among a wide variety of fringe scientists. At the very least, then, it seems to me that anyone who claims to be a science defender, but questions the reality of human-induced climate change, should have to answer the following question: Why trust the mainstream scientific community on other issues but not this one? One possible response—dismissing today’s climate science as warped by environmentalist alarmism—strikes me as simply untenable. If we truly believe that ideology can so corrupt the scientific method in one field, then why place any more trust in the rest of science?
Though they’ve won major media coverage for their effort, it’s tough to say whether the forays of Kennedy and colleagues will truly impact our politics. Certainly little can be expected in an election year. Still, when leading scientists descend upon Washington and loudly ring the alarm bells, it would be the height of folly not to treat their warnings with the utmost seriousness. Just like the vice-president character in Day After Tomorrow, any politician who does otherwise may have a painful apology to make later.