The White House said Friday that chances for an actual deal at this month's global-warming summit in Copenhagen are improving, and with just days until the meeting begins, climate researchers stepped up their fight against what they say is a "smear campaign" by global-warming naysayers.
"It's an 11th-hour smear campaign where they've stolen personal e-mails from scientists, mined them for single words or phrases that can be taken out of context and misrepresent what scientists are saying," said Michael Mann, director of Pennsylvania State University's Earth Systems Science Center, in a teleconference Friday with reporters.
Mr. Mann's research has been aired over the Internet since a security breach in which thousands of e-mails between prominent American and British climate-change scientists were hacked. Global-warming skeptics say the private correspondence could prove that climate data have been hoarded and manipulated by leading climate scientists to overstate the case for human-caused global warming.
The fight over the data comes just as the U.N. summit is about to get under way.
President Obama has rearranged his schedule and now will travel to Copenhagen at the end of the conference on Dec. 18, rather than next week as originally planned.
Press secretary Robert Gibbs said that with India and China agreeing in recent days to set targets for greenhouse gas emissions, there is an opportunity for leaders to finalize a deal that would commit nations to spending $10 billion to help developing nations cope with global warming.
Meanwhile, climate scientists warned that cooler temperatures in North America last year do not mean global warming is easing.
The researchers said that cooler Pacific Ocean waters kept North American temperatures down, but that the rest of the world continued to warm.
The science increasingly is being scrutinized after the e-mail disclosures, and the methodology of scientists such as Mr. Mann is under question.
But he defended his methods.
"I've done nothing wrong; I have nothing to hide; I think my record stands for itself," he said.
The e-mails appear to reveal efforts to prevent scientists skeptical of climate change from publishing materials in major science journals. The e-mails were stolen two weeks ago from the University of East Anglia, a well-regarded British research unit.
The Penn State researcher is best known for his "hockey stick" theory of global warming, which suggests that the past five decades have been the hottest and that humans are to blame.
President Obama's top science adviser, John Holdren, wrote one of the leaked e-mails and testified on climate-change science Wednesday at a congressional hearing on global warming.
Mr. Holdren said that some of Mr. Mann's methods are unconventional, but he agreed with his conclusion that the world is warming.
As a result of the breach, Penn State officials are looking into Mr. Mann's e-mails. University of East Anglia officials are also investigating the breach, and a top researcher there has left his post temporarily while the probe proceeds.
Mr. Mann said he welcomed the inquiry and thinks Penn State officials are simply "researching information to determine if an investigation is necessary."
One of Mr. Mann's e-mails read: "I think we have to stop considering 'Climate Research' as a legitimate peer-reviewed journal. ... We also need to consider what we tell or request of our more reasonable colleagues who currently sit on the editorial board. ..."
Mr. Mann defended his statements, saying: "There was an editor who appeared to be, in essence, gaming the system to allow through papers that did not meet the basic standards of science, simply because they expressed a contrarian viewpoint about climate." He added there is nothing wrong with skeptical science being published, but in this case, the basic standards of quality had been compromised.
Still, the problems may be expanding.
On Thursday, two Republican senators asked NASA to look into why it has not yet answered a researcher who filed a Freedom of Information Act request two years ago seeking temperature data and e-mails similar to the ones from the British university.
In 2007, NASA made corrections to its data that showed 1934, not 1998, was the hottest year on record for the contiguous 48 U.S. states. Researcher Christopher C. Horner, a senior fellow at the Competitive Enterprise Institute, told The Washington Times he has filed three FOIA requests and will sue at the end of this year if the requests aren't answered.
A NASA spokesman told The Times this week that it is still processing the request and that he couldn't say why it's taken so long.
U.S. law gives the agency 20 days to respond to the request, and Mr. Horner said he suspects NASA is delaying because it is afraid of what the data would show.
On Friday, 20 congressional Republicans, including the top House GOP leadership, sent a letter to the president expressing their "grave concern" that the U.S. delegation might commit to mandatory greenhouse gas emissions reductions.
"Only a treaty ratified by the United States Senate or legislation agreed to by Congress may commit our nation to any mandatory emissions reduction program," wrote the Republican lawmakers.
"Congress has the sole responsibility to approve such a program," they added, asking for clarification "that the U.S. negotiators will not commit our government to an emissions-reduction protocol at Copenhagen."
The letter was signed by the two top-ranking Republicans in the House, Rep. John A. Boehner of Ohio and Eric Cantor of Virginia, as well as 18 other GOP lawmakers. It reflected their strong opposition to legislation that would reduce U.S. greenhouse gas emissions from power plants and industry by 17 percent by 2020.
The House narrowly passed the bill last summer, but it has stalled in the Senate, which is expected to take up climate legislation in the spring.
Mr. Obama has said the United States is prepared to commit to reductions in the 17 percent range by 2020 in negotiations at Copenhagen.
But the degree of commitment the Obama administration is prepared to make at Copenhagen has worried some congressional Democrats as well.
On Thursday, nine Democratic senators wrote to the president that, while they remain committed to tackling climate change, they want assurances that any agreement reached at the conference "is environmentally sound, affordable and fair," and includes "significant commitments and actions by all major emitting countries."
"Poorly designed climate policies could jeopardize U.S. national interests by imposing burdens on U.S. consumers, companies and workers without solving the climate challenge," the Democrats cautioned.
c This story is based in part on wire service reports.