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.. . .
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.