JIM LEHRER: Next: climate science and climate scientists under scrutiny.
The United Nations today announced the launch of an independent review of the science behind landmark reports on global warming that were issued by an international panel. That comes after a growing backlash following news of some mistakes.
Jeffrey Brown has our report.
MAN: The Peace Prize laureate for 2007, the Intergovernmental Panel on Climate Change.
JEFFREY BROWN: After years of study and debate, an understanding of climate change, that the Earth is warming and that humans are contributing, received the imprimatur of the Nobel Peace Prize.
AL GORE, former vice president of the United States: I want to thank the Nobel Committee. And it is even more significant because I have the honor of sharing it with the IPCC.
JEFFREY BROWN: The prize was shared by former Vice President Al Gore, who had given the issue a major public voice, and a little-known U.N. group charged with pulling together the science, the Intergovernmental Panel on Climate Change, or IPCC.
It was a heady moment. And, two years later, on the eve of the Copenhagen talks, expectations were high.
CONNIE HEDEGAARD, former president, United Nations Climate Change Conference: The science has never been clearer. The solutions have never been more abundant. Political will has never been stronger.
JEFFREY BROWN: But that's not how it turned out. Instead, Copenhagen concluded without a binding framework, leaving climate policy in limbo.
YVO DE BOER, former executive secretary, United Nations Framework Convention on Climate Change: An impressive accord, but not an accord that is legally binding, not an accord that, at this moment, pins down industrialized countries to individual targets.
JEFFREY BROWN: And there was more, as the U.N. panel and scientists have found themselves on the defensive. In November came the revelations known as climategate, when illegally hacked e-mails sent by several prominent British researchers opened them to charges they were concealing contrary data and evading some public scrutiny.
More recently, the blogosphere has been alive with damning blasts at what critics see as shoddy work, poor sourcing and other problems in the IPCC's 2007 report -- among the examples, a statement that glaciers in the Himalayas will melt entirely by 2035, far faster than scientists have claimed, and which turned out to come from a popular science magazine, rather than a peer-reviewed paper, and a sentence saying that up to 40 percent of the Amazonian forests could react drastically to even a slight reduction in precipitation. That turned out to be linked to a report by the World Wildlife Fund, an advocacy group.
STEPHEN SCHNEIDER, climate scientist, Stanford University: I mean, I'm embarrassed by it. That -- that the Himalayan glaciers would melt in 2035, that's ridiculous. It should not have been there.
JEFFREY BROWN: Stephen Schneider, a climate scientist at Stanford, worked on the last IPCC report.
STEPHEN SCHNEIDER: The unfortunate part of this real error about the date of melting is, it has detracted from the correct conclusion, which is that Himalayan glaciers are melting rapidly, and that has tremendous social importance, in terms of the risk of floods now and drought later.
So, the basic relevance in the science is right. The absolute date is ridiculous. And it was just a glitch that everybody missed.
JEFFREY BROWN: Schneider points out that the IPCC reports pull together the work of hundreds of volunteer scientists, who sift through thousands of studies, weighing the evidence for climate change.
STEPHEN SCHNEIDER: It's a series of refinements and approximations that get better and better. When the temple of high science is found to have made an error or two, people say, oh, my God, we can't trust them.
But take a look at the error rate. The IPCC, which has been attacked for making errors -- correct, there were errors, absolutely right. I'm involved in the IPCC, and we're not proud of a few errors. But how many? Three? How many conclusions? A thousand? Tell me any other human institution dealing with complexity that has a 1 percent error rate.
JEFFREY BROWN: In other words, Schneider and most of his colleagues say, the consensus holds. Errors? Yes. But a change in the conclusion on warming and its causes? No way.
Still, the errors did create a giant opening to skeptics of the science of warming and of the IPCC process.
PATRICK MICHAELS, climatologist, Cato Institute: Individually, they care not particularly serious, but it is the mechanism that they imply that is very serious.
JEFFREY BROWN: One is Patrick Michaels, a climatologist with the Cato institute and senior fellow at George Mason University. He says the revelations confirm what he's long claimed: that IPCC reports reach precooked conclusions.
PATRICK MICHAELS: The problem with the Himalayan glaciers was that it was such an obvious error that the -- the climatologist who was listed as the first author for that particular chapter would have clearly picked it up if his eyes saw the number. So, we can only assume that his eyes didn't see the number. And that is very telling. It shows that the process, IPCC process, was allowed to get very, very fast and very, very loose.
JEFFREY BROWN: For Michaels, what's needed is more transparency. And the place for that is on the Internet, where information flows, studies are put forward, and facts are checked by all kinds of people, obviating the need for a group like the IPCC.
PATRICK MICHAELS: I don't see why we need it. I don't see why we needed a fourth assessment report. I mean, the purpose of the IPCC was to provide the background for a framework convention on climate change. It morphed into a totally different purpose, so far as I can tell, which was to -- to cheerlead for policies on climate change. And don't tell me that they were not doing that.
JEFFREY BROWN: Even scientists who back the U.N. panel and the overall findings of its reports are calling for more openness and say many researchers haven't dealt with these problems adequately.
Judith Curry is a climate scientist at Georgia Tech who contributed to an early IPCC report.
JUDITH CURRY, climate scientist, Georgia Institute of Technology: I don't we're learning, the scientific community, is learning the right lessons. I mean, the reaction from the scientific community has been mostly, you know, nothing to see here, let's move on, it doesn't really affect the science.
And they were basically appealing to their own authority, but they didn't realize that that wasn't going to work, when it was really the trust. People were not really questioning the expertise of the scientists, but they were questioning whether they really could trust this whole process and what had gone on, in light of some of these revelations.
JEFFREY BROWN: And there are signs that public trust has eroded. Several recent polls show a drop in the public's belief that climate change is real and should be a top political priority.
To help shore up that trust, the U.N. has just announced it will appoint an independent board of scientists to review the work of the IPCC. Several other reviews here and abroad are also under way.
MAN: Yeas are 219. Nays are 212.
JEFFREY BROWN: In the meantime, prospects for passing climate change legislation in the U.S. have dimmed. The House passed an energy bill last summer that included national reductions in carbon emissions. But that bill stalled in the Senate, and less ambitious measures are now being considered.