OTTAWA - Stephen Harper, who now styles himself as a green prime minister, once ridiculed the Kyoto accord as a money-sucking socialist scheme and promised he would battle to defeat it.

His scathing view of the global treaty, which questioned the science of climate change, was included in a 2002 fundraising letter sent to members of his now-defunct Canadian Alliance party.

With polls showing the environment is a top priority with voters and Harper keen to bolster his environmental credentials ahead of the next election, the letter could be a big embarrassment.

It was circulated Tuesday by the Liberals, who said it unmasks Harper as a climate-change denier.

"Kyoto is essentially a socialist scheme to suck money out of wealth-producing nations,'' says the letter, signed by Harper.

"Implementing Kyoto will cripple the oil and gas industry, which is essential to the economies of Newfoundland, Nova Scotia, Saskatchewan, Alberta and British Columbia . . .

"Workers and consumers everywhere in Canada will lose. THERE ARE NO CANADIAN WINNERS UNDER THE KYOTO ACCORD.''

Harper, who now accuses the Liberals of having done nothing to reduce greenhouse gases, went on to promise a "battle'' to defeat the Chretien Liberals' efforts to introduce Kyoto-implementation legislation in the House of Commons.

"But we can't do it alone. It will take an army of Canadians to beat Kyoto, just as it did to beat (the) Charlottetown (constitutional accord),'' he wrote.

These days, Harper avoids critcizing the Kyoto accord, and simply dismisses its targets as unattainable.

Kyoto calls for a six per cent cut in greenhouse gas emissions from 1990 levels by 2012. Canada's emission levels have risen 27 per cent since 1990.

Now, with public-opinion polls indicating that climate change is becoming a dominant political concern for Canadians, the prime minister is promising serious action.

He intends to introduce a vastly revamped version of his Clean Air Act in the coming months. The original legislation has been ridiculed by opponents and opinion-makers as a work in progress that fails to set reduction targets before 2050.

The Liberals said the letter proves Harper isn't serious about tackling climate change.

"It's no wonder Mr. Harper's sudden change of heart is hard for Canadians to swallow,'' said Liberal MP Mark Holland.

"Now, suddenly, because he has seen the polls and realized the political opportunism of going `green,' the prime minister has launched a new campaign -- that of trying to convince Canadians that he actually cares about the environment.

"Well, no one is buying it.''

The Prime Minister's Office refused to comment about the letter on the record.

A new poll released to The Canadian Press suggests Canadians are indeed skeptical about the government's environmental commitment.

Sixty-four per cent of the 1,023 respondents in the Decima survey said they believe recent Tory announcements are being driven by polls rather than conviction.

The Liberals also came in for criticism on the climate-change file Tuesday.

The NDP, which appears to be co-operating with the Tories on revamping the Clean Air Act, accused the Liberals of trying to stall the debate at a special legislative committee.

The Liberals and Bloc succeeded in gaining a two-week extension that will push the deadline for the committee's work to March 30.

The NDP says that's because the Liberals want to make sure the new bill can't pass before the federal budget -- a confidence item which could mean the defeat of the minority government.

"(Liberals) would prefer that nothing gets done in this Parliament with respect to the environment,'' said New Democrat MP Nathan Cullen.

"The Liberals are dedicated to the idea that they've got a one-trick pony as a leader. (Stephane Dion) must present an environmental cause to Canadians -- and they are willing to sacrifice the environment in order for that political gain.''