A group of veteran pranksters have stepped forward to say they are responsible for a series of fake news releases sent out Monday that claimed Canada had committed to drastic greenhouse gas emission cuts.

The U.S.-based Yes Men told The Associated Press they launched the complicated hoax to expose what the group feels is Canada's failure to take tough action to reduce greenhouse gas emissions.

A first fake announcement released around 8 a.m. ET Monday claiming to originate from Environment Canada said Canada had drastically changed its greenhouse gas emission reduction targets to levels preferred by environmentalists. The cuts in emissions cited were significantly greater than those Canada has publicly committed to.

Reporters who received the announcement at the United Nations climate change summit in Copenhagen were skeptical, however, as the stance in the email seemed particularly far off the government's public comments to date.

The broadly distributed email attributed quotes to Environment Minister Jim Prentice, who is in Copenhagen representing Canada at the summit, which the United Nations hopes will lead to a replacement agreement to the Kyoto Protocol that expires in 2012.

The email also provided links to a fake website designed to mirror the appearance of the Environment Canada website. However, its address was at www.enviro-canada.ca and not www.ec.gc.ca, the actual address of the ministry.

Two subsequent releases, both also fake, added to the complexity of the hoax. The first included comments attributed to a member of the Ugandan delegation praising Canada's decision.

A third release claiming to be from the government said the previous two releases were spoofs, but then attributed quotes to Prentice and others that put Canada's environmental policies in a poor light.

A website made to look like the Wall Street Journal also had an article detailing the fabricated news.

The Yes Men, led by U.S. university professors Igor Vamos (alias Mike Bonanno) and Jacques Servin (Andy Bichlbaum), have made headlines for embarrassing climate-change skeptics and corporate malefactors. They grabbed attention earlier this year when they held a fake news conference and announced that the U.S. Chamber of Commerce had reversed its position on climate change.

In perhaps their most widely reported stunt, they appeared on the BBC in 2004 impersonating a Dow Chemical executive, taking full responsibility for the 1984 Bhopal disaster in India — one of the world's worst industrial disasters.

Heated exchange

PMO spokesman Dimitri Soudas, left, confronts Steven Guilbeault in Copenhagen on Monday. Soudas sent an email to reporters suggesting a hoax email might have been issued by Guilbeault. (CBC)

Dimitri Soudas, a Prime Minister's Office spokesman who is attending the climate change conference in Denmark's capital, lambasted the hoax news releases.

"Time would be better used by supporting Canada's efforts to reach an agreement instead of sending out hoax press releases," Soudas wrote in an email to CBC News. "More time should be dedicated to playing a constructive role instead of childish pranks."

Before the Yes Men took responsibility, Soudas got in a heated exchange with Steven Guilbeault from the environmental group Equiterre, after Soudas sent an email to reporters saying the hoax may have been issued by Guilbeault.

"I had nothing to do with this and I demand an apology," Guilbeault said in an email to CBC News. "The Harper government is pointing fingers at me for saying the truth."

Guilbeault said he was singled out because the government doesn't like what he has said about Canada's record on climate change.

The initial release claimed the government had committed to reduce emissions by 40 per cent below 1990 levels, a target favoured by environmental groups but one far more stringent than the commitments of developed countries.

Canada has committed to reduce emissions by 20 per cent below 2006 levels by 2020, still a far cry from the standards of the Kyoto Protocol.

Canada target at Copenhagen

Canada's federal government has been a frequent target of environmental protests for its emission reduction targets and for including Alberta's oilsands and tarsands in its energy policies.

Toronto Mayor David Miller lamented on Monday that late last week, he had been given a Fossil of the Day Award for Canada's role in the Copenhagen talks.

And on Sunday, the federal government faced criticism from both Quebec Premier Jean Charest and Ontario Environment Minister John Gerretsen for its modest emission reduction targets.

Leaders from over 100 countries will be meeting later this week in Copenhagen to try to establish a framework for a new global climate change treaty.

With files from The Canadian Press