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.