The most serious criticisms leveled at the authors of the e-mail messages revolve around three issues.

One is whether the correspondence reveals efforts by scientists to shield raw data, gleaned from tree rings and other indirect indicators of climate conditions, preventing it from being examined by independent researchers. Among those who say it does is Stephen McIntyre, a retired Canadian mining consultant who has a popular skeptics’ blog, climateaudit.org. A second issue is whether disclosed documents, said to be from the stolen cache, prove that the data underlying climate scientists’ conclusions about warming are murkier than the scientists have said. The documents include files of raw computer code and a computer programmer’s years-long log documenting his frustrations over data gathered from countries in the Northern Hemisphere.

Finally, questions have been raised about whether the e-mail messages indicated that climate scientists tried to prevent the publication of papers written by climate skeptics, which were described by the scientists in the e-mail messages as “garbage” and “fraud.”

Officials with Britain’s national climate office have defended the integrity of the climate unit’s work, noting that the warming trend it has measured is largely replicated by separate groups at NASA and the National Oceanic and Atmospheric Administration. “This is a shallow and transparent attempt to discredit the robust science undertaken by some of the world’s most respected scientists,” said Vicky Pope, the office’s senior spokeswoman, in an e-mail message.

Rajendra K. Pachauri, the chairman of the intergovernmental climate panel, issued a statement rebutting claims that the e-mail messages, which involved some members of the panel, indicated that the panel’s reports were biased. In posts on the blog Realclimate.org, some of the scientists who participated in the correspondence have also said that, although inappropriate language was used at times, their critical comments about people or research papers were based on the quality of the arguments.

The public disclosure of the e-mail messages has already led to calls from conservative British and American legislators for investigations.

The lead Saudi Arabian climate negotiator, Mohammad al-Sabban, said that the affair could affect negotiations over a new global climate treaty. “This is very serious and can put the whole climate debate, including any future agreement in Copenhagen and beyond, in big question,” Mr. al-Sabban said in an e-mail message. And even some environmental campaigners believe that the disclosures have damaged calls for climate action. George Monbiot, a British environmentalist and author, excoriated some of the climate unit’s scientists and many of his fellow activists on Wednesday in a column in The Guardian.