An Inconvenient Truth

Swift Boating the Planet
By PAUL KRUGMAN

A brief segment in "An Inconvenient Truth" shows Senator Al Gore questioning James Hansen, a climatologist at NASA, during a 1989 hearing. But the movie doesn't give you much context, or tell you what happened to Dr. Hansen later.

And that's a story worth telling, for two reasons. It's a good illustration of the way interest groups can create the appearance of doubt even when the facts are clear and cloud the reputations of people who should be regarded as heroes. And it's a warning for Mr. Gore and others who hope to turn global warming into a real political issue: you're going to have to get tougher, because the other side doesn't play by any known rules.

Dr. Hansen was one of the first climate scientists to say publicly that global warming was under way. In 1988, he made headlines with Senate testimony in which he declared that "the greenhouse effect has been detected, and it is changing our climate now." When he testified again the following year, officials in the first Bush administration altered his prepared statement to downplay the threat. Mr. Gore's movie shows the moment when the administration's tampering was revealed.

In 1988, Dr. Hansen was well out in front of his scientific colleagues, but over the years that followed he was vindicated by a growing body of evidence. By rights, Dr. Hansen should have been universally acclaimed for both his prescience and his courage.

But soon after Dr. Hansen's 1988 testimony, energy companies began a campaign to create doubt about global warming, in spite of the increasingly overwhelming evidence. And in the late 1990's, climate skeptics began a smear campaign against Dr. Hansen himself.

Leading the charge was Patrick Michaels, a professor at the University of Virginia who has received substantial financial support from the energy industry. In Senate testimony, and then in numerous presentations, Dr. Michaels claimed that the actual pace of global warming was falling far short of Dr. Hansen's predictions. As evidence, he presented a chart supposedly taken from a 1988 paper written by Dr. Hansen and others, which showed a curve of rising temperatures considerably steeper than the trend that has actually taken place.

In fact, the chart Dr. Michaels showed was a fraud — that is, it wasn't what Dr. Hansen actually predicted. The original paper showed a range of possibilities, and the actual rise in temperature has fallen squarely in the middle of that range. So how did Dr. Michaels make it seem as if Dr. Hansen's prediction was wildly off? Why, he erased all the lower curves, leaving only the curve that the original paper described as being "on the high side of reality."

The experts at www.realclimate.org, the go-to site for climate science, suggest that the smears against Dr. Hansen "might be viewed by some as a positive sign, indicative of just how intellectually bankrupt the contrarian movement has become." But I think they're misreading the situation. In fact, the smears have been around for a long time, and Dr. Hansen has been trying to correct the record for years. Yet the claim that Dr. Hansen vastly overpredicted global warming has remained in circulation, and has become a staple of climate change skeptics, from Michael Crichton to Robert Novak.

There's a concise way to describe what happened to Dr. Hansen: he was Swift-boated.

John Kerry, a genuine war hero, didn't realize that he could successfully be portrayed as a coward. And it seems to me that Dr. Hansen, whose predictions about global warming have proved remarkably accurate, didn't believe that he could successfully be portrayed as an unreliable exaggerator. His first response to Dr. Michaels, in January 1999, was astonishingly diffident. He pointed out that Dr. Michaels misrepresented his work, but rather than denouncing the fraud involved, he offered a rather plaintive appeal for better behavior.

Even now, Dr. Hansen seems reluctant to say the obvious. "Is this treading close to scientific fraud?" he recently asked about Dr. Michaels's smear. The answer is no: it isn't "treading close," it's fraud pure and simple.

Now, Dr. Hansen isn't running for office. But Mr. Gore might be, and even if he isn't, he hopes to promote global warming as a political issue. And if he wants to do that, he and those on his side will have to learn to call liars what they are.