Five investigations into the "Climategate" scandal have now cleared a group of scientists accused of twisting data in an effort to prove the world is getting warmer.


The scandal spawned big headlines and heated blog posts when it erupted last fall after hackers released a stash of unflattering e-mails from a climate research lab in Britain. In one message, a scientist wrote of using a "trick" to "hide the decline" in temperature-proxy data from tree rings. Global warming doubters claimed vindication.

British and American investigations have now largely exonerated the scientists, saying they did not warp their studies to reach a pre-determined end. But the public may not buy it. Some polls show the public's belief in the reality of climate change has ebbed, although other surveys disagree.

"Despite multiple denials from people in the field, this has really hurt," said Daniel Kammen, a UC Berkeley professor who contributes to reports by the Intergovernmental Panel on Climate Change. The accuracy of the IPCC's reports, long considered the most authoritative on global warming, came under fire during Climategate.

"Even though the science of climate change hasn't changed, the public perception of it has," Kammen said. "You have less than 50 percent of people strongly believing in something that 99.99 percent of climate scientists agree on."

Exonerations downplayed

The exonerations haven't generated anything like the intense media coverage that the initial scandal did. Newspapers have typically covered them with small stories far removed from the front page - or ignored them altogether.

"The accusations were on A1, the exonerations are usually on A15," said Aaron Huertas, press secretary for the Union of Concerned Scientists.

Climategate's lingering effects could play a role in the debate over global warming legislation, both in Congress and in California. The U.S. Senate is expected to take up an energy and climate change bill in the next two weeks. And in California, voters this fall will decide whether to suspend the state's landmark global warming law, AB32.

"In general, I think the scandal has made the opponents of energy-rationing legislation stronger and more confident," said Myron Ebell, director of energy and global warming policy for the Competitive Enterprise Institute think tank.

Ebell, who for years has been one of the fiercest critics of global warming science, doubts that Climategate by itself changed any votes in the Senate. But the scandal may have solidified skepticism about climate science among the public, he said. That would make any global warming bill harder for Senate Democrats to pass.

"The American public opposes policies that are going to raise their energy prices," Ebell said. "And I just don't see how they can get around that."

Climategate featured accusations that scientists were fudging data, colluding to silence critics and stonewalling public requests for information. The investigations to date have discounted the most serious charges.

Scientists cleared, chided

Earlier this month, for example, a British panel found that the researchers at the center of the scandal, working at the Climatic Research Unit of the University of East Anglia, were not guilty of scientific malpractice, saying "their rigor and honesty as scientists are not in doubt." The panel found no evidence that the scientists' behavior had undermined the accuracy of the IPCC reports, which relied on their contributions.

The panel found nothing wrong with the "trick" referenced in the controversial e-mail, saying it was a valid technique for handling the data, which was used to produce a widely seen graph tracking temperature changes over the last millennium. But the panel criticized the scientists for not making clear, either in the graph or in its caption, that they were using that technique. Without the explanation, the panel said, the graph was "misleading."

The panel's findings, however, haven't drawn as much attention as the original charges. Tom Hollihan, who teaches media and politics at the University of Southern California, said that isn't unusual.

"The story that sticks is the first story out there that shapes the conversation," said Hollihan, who teaches in the university's Annenberg School for Communication & Journalism. "The story about a conspiracy to manipulate the data had a unique appeal to people who are drawn naturally to stories about conspiracies and being misled. The more you refute them, the more evidence those people see that the conspiracy is very pervasive."

Ebell and other critics call the investigations a farce, saying they represent an attempt by the academic community to defend their own.

Affect on public opinion

"These establishment reports to whitewash this scandal - they have no credibility," Ebell said. "It's pretty obvious that they're not independent inquiries, that they were designed to come up with an exoneration. You need (an investigation with) people who don't have connections, who haven't written papers with the people who are accused or served on faculty with them."

How much the scandal affected public opinion isn't clear.

A Gallup poll released in March found that 48 percent of Americans believe the seriousness of climate change is usually exaggerated, up from 41 percent in 2009. But other recent polls say a majority of Americans still consider global warming a major problem and want the federal government to address it.

A survey released in June by Stanford University Professor Jon Krosnick found that 74 percent of Americans believe the climate probably grew warmer in the past century. While that figure is down from 84 percent in 2007, Krosnick attributed the decline to short-term changes in the weather, not Climategate. Indeed, only 9 percent of the people surveyed had heard about the hacked e-mail messages.

"At the end of the day, I feel people still see what's happening - they're seeing the heat waves, they're seeing the fires, they know the ice is thinning," said Sen. Barbara Boxer, D-Calif. "The last decade, we know, is the warmest on record, and no e-mails are going to change that."

Still, environmentalists fear that Climategate will make passing federal global warming legislation, already a difficult task, that much tougher.

"If members of Congress believe that - because of the coverage of so-called Climategate - the public is less concerned about the impacts of global warming, some of the senators who are on the fence may feel less compelled to vote for legislation that curbs global warming pollution," said Dan Lashof, director of the Natural Resources Defense Council's climate center. "That's the real danger in this."