E-mails stolen from climate scientists show they stonewalled sceptics and discussed hiding data – but the messages don't support claims that the science of global warming was faked, according to an exhaustive review by the Associated Press.

In the past three weeks since the emails were posted, longtime opponents of mainstream climate science have repeatedly quoted excerpts of about a dozen emails. Republican congressmen and former vice presidential candidate Sarah Palin have called for either independent investigations, a delay in US Environmental Protection Agency regulation of greenhouse gases or outright boycotts of the Copenhagen international climate talks.

The 1,073 emails examined by the AP show that scientists harboured private doubts, however slight and fleeting, even as they told the world they were certain about climate change. However, the exchanges don't undercut the vast body of evidence showing the world is warming because of man-made greenhouse gas emissions.

The scientists were keenly aware of how their work would be viewed and used, and, just like politicians, went to great pains to shape their message. Sometimes, they sounded more like schoolyard taunts than scientific tenets.

The scientists were so convinced by their own science and so driven by a cause "that unless you're with them, you're against them," said Mark Frankel, director of scientific freedom, responsibility and law at the American Association for the Advancement of Science.

He also reviewed the communications.

Frankel saw "no evidence of falsification or fabrication of data, although concerns could be raised about some instances of very 'generous interpretations'."

Some emails expressed doubts about the quality of individual temperature records or why models and data didn't quite match. Part of this is the normal give-and-take of research, but sceptics challenged how reliable certain data was.

The emails were stolen from the computer network server of the climate research unit at the University of East Anglia in southeast England, an influential source of climate science, and were posted online last month. The university shut down the server and contacted the police.

The AP studied all the e-mails for context, with five reporters reading and rereading them - about one million words in total.

One of the most disturbing elements suggests an effort to avoid sharing scientific data with critics sceptical of global warming. It is not clear if any data was destroyed; two US researchers denied it.

The emails show that several mainstream scientists repeatedly suggested keeping their research materials away from opponents who sought it under American and British public records law. It raises a science ethics question because free access to data is important so others can repeat experiments as part of the scientific method. The University of East Anglia is investigating the blocking of information requests.

"I believe none of us should submit to these 'requests,'" declared the university's Keith Briffa. The centre's chief, Phil Jones, wrote: "Data is covered by all the agreements we sign with people, so I will be hiding behind them."

The e mails also show how professional attacks turned very personal and also showed a stunning disdain for global warming sceptics.

One scientist practically celebrates the news of the death of one critic, saying, "In an odd way this is cheering news!"

Another bemoans that the only way to deal with sceptics is "continuing to publish quality work in quality journals (or calling in a Mafia hit)." And a third scientist said the next time he sees a certain sceptic at a scientific meeting, "I'll be tempted to beat the crap out of him. Very tempted."

And they compared contrarians to communist-baiting senator Joseph McCarthy and Somali pirates. They also called them out-and-out frauds.