LONDON--The head of the U.N.'s panel of climate experts rejected accusations of bias on Thursday, saying a "Climategate" row in no way undermined evidence that humans are to blame for global warming.
Climate change skeptics have seized on a series of e-mails written by specialists in the field, accusing them of colluding to suppress data which might have undermined their arguments.
The e-mails, some written as long as 13 years ago, were stolen from a British university by unknown hackers and spread rapidly across the Internet.
But Rajendra Pachauri, who chairs the Intergovernmental Panel on Climate Change (IPCC), stood by his panel's 2007 findings, called the Fourth Assessment Report (AR4). "This private communication in no way damages the credibility of the AR4 findings," he told Reuters in an e-mail exchange.
This report helped to underpin a global climate response which included this week carbon emissions targets proposed by the United States and China, and won the IPCC a share of the 2007 Nobel Peace Prize.
The e-mails hacked from Britain's University of East Anglia last week showed scientists made snide comments about climate skeptics, and revealed exchanges about how to present the data to make the global warming argument look convincing.
In one e-mail, confirmed by the university as genuine, a scientist jokingly referred to ways of ensuring papers which doubted established climate science did not appear in the AR4.
Pachauri said a laborious selection process, using only articles approved by other scientists, called peer review, and then subsequently approving these by committee had prevented distortion.
"The entire report writing process of the IPCC is subjected to extensive and repeated review by experts as well as governments," he added in a written statement to Reuters.
"There is, therefore, no possibility of exclusion of any contrarian views, if they have been published in established journals or other publications which are peer reviewed."
"This thoroughness and the duration of the process followed in every assessment ensure the elimination of any possibility of omissions or distortions, intentional or accidental."
In another e-mail, according to news accounts, Kevin Trenberth, a climatologist at the National Center for Atmospheric Research, wrote: "The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't." The revelation of the e-mails was more embarrassing than serious fodder for doubts about the causes of, or basis for climate change, scientists responded this week.
"It is unfortunate that an illegal act of accessing private e-mail communications between scientists who have been involved as authors in IPCC assessments in the past has led to several questions and concerns," said Pachauri.