Business interests and US partisan politics are behind the furor over leaked emails that have whipped up a controversy at the Copenhagen climate talks, Canadian experts say.

The global talks to hammer out a deal on curbing greenhouse gas emissions are being derailed by public attention on the so-called "Climategate," scientist Andrew Weaver and author James Hoggan told AFP.

Intercepted from scientists at Britain's University of East Anglia, a top center for climate research, the emails have been seized upon by skeptics as evidence that experts twisted data in order to dramatize global warming.

Some of the thousands of messages expressed frustration at the scientists' inability to explain what they described as a temporary slowdown in warming.

The controversy "gives voice to dissenters at the table in Copenhagen, like Saudi Arabia and Russia," said Hoggan, author of "Climate Cover-up" about big-business funding of opponents of environmental causes.

But more importantly, he said, the success of the treaty being hammered out in Copenhagen in talks until December 18 will depend on the United States, where political opposition to climate change is "driven by an extremist view."

"A lot of this is just about politics in the US, and this undermines political will in the US," Hoggan told AFP.

The email messages containing words like "trick" between climate scientists, were apparently stolen from the Climatic Research Unit at the University of East Anglia and recently released on the Internet.

They have triggered an investigation by the university and the United Nations Intergovernmental Panel on Climate Change (IPCC).

Canada's Globe and Mail daily newspaper said the emails "revealed a dangerous bunker mentality among the scientists" and "a crisis of confidence in global-warming science."

But Hoggan said close examination shows the email messages are not "scandalous," and the real issue is the identities of whomever stole them and is "attempting to create or fabricate this scandal."

"We are at a pivotal moment in human history in terms of reaching a post-Kyoto agreement on regulating greenhouse gases," Weaver, a Canadian scientist on the IPCC, told a press conference Thursday.

Weaver said two men tried to hack emails in computers at the Canadian Center for Climate Modeling and Analysis in his building at the University of Victoria -- but left when workers challenged them.

He also read out examples of dozens of hate emails and phone messages he said he receives each day from people who do not believe human activity is responsible for global warming.

"Each and every time an IPCC report is released... very similar things happen," said Weaver. "If you don't like the message you try to discredit the messenger."

"There is a war on science," he added, alleging it was being led by right-wing ideologues and business interests and their tactics "exploit a lack of scientific literacy in the general public."

"An all-out attack on the validity of climate science has been undertaken by industry groups," agreed Hoggan, whose book is based on four years of research into the funding of climate deniers.

"Groups like the Competitive Enterprise Institute, Heartland Institute and the Committee for a Constructive Tomorrow have been at the core of a decade-long campaign to delay government action to reduce greenhouse gas emissions," Hoggan said in a press release.

Opponents of the climate treaty, however, call the scientists "alarmists" and dispute that there is a consensus among scientists about climate change.

"The science behind global warming alarmism is falling apart from within, and the Climategate documents demonstrate why," said Sam Kazman, from the Competitive Enterprise Institute, in an email to AFP.

"There's been no statistically significant warming over the last 10-15 years, despite increasing levels of supposedly dangerous CO2.

"CEI is proud to have helped delay the energy rationing sought by the alarmists, and we plan to continue doing so in several ways, including our announced intention to challenge EPA's Endangerment finding in court."

And Dan Miller of the Chicago-based Heartland Institute alleged the British scientists had felt "so threatened by skeptics' contrary findings that they deleted or manipulated their own data."