03/18/2010 05:12 am ET Updated May 25, 2011

All Real Scientists Are Climate Skeptics

The emails stolen from climate researchers at East Anglia University and released online--"Climategate," as it has come to be known to some--may say a lot about some of the scientists involved. But they also reveal much about the dangerous political atmosphere into which the messages have emerged, coincidental with the Copenhagen climate summit. Scientists need to take a long, hard look at the implications.

Some messages seem to suggest unethical behavior on the part of correspondents, including plans to delete information requested under freedom of information laws. Others seem fuzzier. One describes an author's decision to omit plotting some data inconsistent with the overarching theory of manmade global warming; depending on your viewpoint, he was simply eliminating a distracting and irrelevant detail--or attempting to hide a fatal flaw. Whichever way you look at it, some of the seeming skullduggery can be ascribed to hubris. But much of it appears motivated by a desire to persuade, rather than advise, the public and policy makers.

Persuasion is becoming increasingly difficult. Last week, a New York Times reporter wrote, "the scientific consensus [is] more or less settled that human activity ... is contributing to a warmer and less hospitable planet." Shortly before that, a Wall Street Journal columnist wrote that "corruption [renders] the global-warming consensus ... fraudulent." It seems that even the most basic scientific data on CO2 and climate are now matters of opinion, viewed through a left- or right-leaning prism. This is a frightening development.

To be sure, some of the polarization results from discord over the policy that should result from climate science, rather than the science itself. Most proposals to avoid or offset CO2 emissions in the United States involve government intervention, including taxes and incentives, plus unprecedented international treaties. This engenders instant opposition from some conservatives--and, no doubt, some support from people with anti-business agendas. If anyone has a good, libertarian idea about how to significantly reduce CO2 emissions, now is the time to come forward. Meanwhile, the science community will be most effective if it focuses on delineating possible outcomes, rather than advocating specific solutions. Above all, this requires credibility.

How much do the stolen emails undermine the hypothesis of human-induced global warming? A Dec. 3 editorial in the journal Nature stated that "the scientific case that global warming is real [and] that human activities are almost certainly the cause ... is supported by multiple, robust lines of evidence, including several that are completely independent of the climate reconstructions debated in the e-mails." Scientists widely share this sentiment, with caveats. However, they need to do more than quarantine a few alleged miscreants and then move ahead as though nothing has happened.

For example, unfortunately, the Nature editorial repeatedly refers to critics of the human-induced global warming hypothesis as "denialists." Similarly, groups on both sides of the debate use the term "skeptic" to refer solely to those who doubt that humans are influencing climate in any way. Such a bunker mentality leads to the impression that skepticism and climate science are incompatible. Somehow, some people have come to believe that if a single study suggesting human-induced climate change is incorrect, the entire scientific basis for the hypothesis is invalidated. A corollary, implicitly adopted by some "believers" and "skeptics" alike, is that predictions of warming due to human CO2 emissions must be almost certain in order to justify major efforts to reduce CO2 output.

If the East Anglia scientists and their correspondents had never existed, there would still be plenty of evidence from other scientists suggesting a significant role for human-induced increases in atmospheric CO2 and temperature over the past century. Nevertheless, everyone involved needs to embrace the idea that all scientists are skeptics; that all scientific theories are open to doubt; and in particular that future projections of climate change are subject to considerable uncertainty. Furthermore, the economic and environmental impacts of warming are also uncertain, as are the costs of CO2 mitigation. When scientists hide these uncertainties, or simply don't discuss them, they lose credibility. Climate scientists are clearly unable to "save the world" alone. But they are stewards of key data that are essential to shape wise policy. Their credibility is much more important than their political opinions.

Does this mean that no political action should be taken until scientific uncertainties are resolved? Of course not. Regardless of divisive tactics among negotiators or malfeasance among some scientists, atmospheric CO2 concentration continues to rise, more rapidly and to higher values than recorded in gas trapped in glacial ice over the past 500,000 years. This is mainly due to use of fossil fuels, and it is pushing us further and further into uncharted territory. Though there are many other factors that influence global climate, there is no doubt that CO2 is a greenhouse gas. And, in addition to the threat of climate change, there are ample reasons to conserve energy and reduce our dependence on fossil fuels. The longer we delay, the higher will be the cost of limiting CO2 in the atmosphere. The cost may be high now, but it will only get higher in the future.

Little was expected from Copenhagen even before the emails clouded the issues. They surely didn't help, and may lower the bar even further. Next spring, the U.S. Senate will consider legislation to limit U.S. emissions. The emails will undoubtedly come up again; and it seems likely that the Senate will once again shrink from doing anything. Many politicians will then breathe a sigh of relief. But that will be premature, to put it mildly, because this is bigger than politics. For scientists, it is time to admit we're uncertain, explain the danger of inaction, and transcend irrelevant political categories. And everyone needs to get serious about dealing with the CO2 problem. It is not going to go away.

Peter Kelemen is a professor of geochemistry at Lamont-Doherty Earth Observatory. In addition to studying volcanoes and earthquakes, he is investigating geological capture and storage of CO2.

His post is part of a continuing series of essays and interviews from Earth Institute experts on the prospects for a global climate-change treaty. Check with our blog State of the Planet daily for news and perspectives, and to make comments, as events unfold throughout the Copenhagen meetings.