New York, Nov. 21: Hundreds of private email messages and documents hacked from a computer server at a British university are causing a stir among global warming sceptics, who say they show that climate scientists conspired to overstate the case for a human influence on climate change.

The email messages, attributed to prominent American and British climate researchers, include discussions of scientific data and whether it should be released, exchanges about how best to combat the arguments of sceptics and casual comments — in some cases derisive — about specific people known for their sceptical views.

Drafts of scientific papers and a photo collage that portrays climate sceptics on an ice floe were also among the hacked data, some of which dates back 13 years.

In one email exchange, a scientist writes of using a statistical “trick” in a chart illustrating a recent sharp warming trend. In another, a scientist refers to climate sceptics as “idiots”.

Some sceptics asserted today that the correspondence revealed an effort to withhold scientific information. “This is not a smoking gun; this is a mushroom cloud,” said Patrick J. Michaels, a climatologist who has long faulted evidence pointing to human-driven warming and is criticised in the documents.

Some of the correspondence portrays the scientists as feeling under siege by the sceptics’ camp and worried that any stray comment or data glitch could be turned against them.

The evidence pointing to a growing human contribution to global warming is so widely accepted that the hacked material is unlikely to erode the overall argument.

However, the documents will undoubtedly raise questions about the quality of research on some specific questions and the actions of some scientists.

In several email exchanges, Kevin Trenberth, a climatologist at the National Center for Atmospheric Research, and other scientists discuss gaps in understanding of recent variations in temperature. Sceptic websites pointed out one line in particular: “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,” Trenberth wrote.

The cache of email messages also includes references to journalists, including this reporter, and queries from journalists related to articles they were reporting.

Officials at the University of East Anglia confirmed in a statement yesterday that files had been stolen from a university server and that the police had been brought in to investigate the breach. They added, however, that they could not confirm that all the material circulating on the Internet was authentic.

But several scientists and others contacted by The New York Times confirmed that they were the authors or recipients of specific email messages included in the file. The revelations are bound to inflame the public debate as hundreds of negotiators prepare to negotiate an international climate accord at meetings in Copenhagen next month, and at least one scientist speculated that the timing was not coincidental.

Trenberth said yesterday that he was appalled at the release of the email messages.

But he added that he thought the revelations might backfire against climate sceptics. He said that he thought that the messages showed “the integrity of scientists”. Still, some of the comments might lend themselves to being interpreted as sinister.