Prime Minister Stephen Harper once called the Kyoto accord a "socialist scheme" designed to suck money out of rich countries, according to a letter leaked Tuesday by the Liberals.

The letter, posted on the federal Liberal party website, was apparently written by Harper in 2002, when he was leader of the now-defunct Canadian Alliance party.

He was writing to party supporters, asking for money as he prepared to fight then-prime minister Jean Chrétien on the proposed Kyoto accord.

"We're gearing up now for the biggest struggle our party has faced since you entrusted me with the leadership," Harper's letter says.

"I'm talking about the 'battle of Kyoto' — our campaign to block the job-killing, economy-destroying Kyoto accord."

The accord is an international environmental pact that sets targets for reducing greenhouse gas emissions.

Canada officially ratified the accord Dec. 17, 2002, under Chrétien's Liberal government. Harper's Conservative government, which took power January 2006, has since been accused of ignoring the accord.

Harper's letter goes on to outline why he's against the agreement.

Accord based on 'contradictory' data: Harper

He writes that it's based on "tentative and contradictory scientific evidence" and it focuses on carbon dioxide, which is "essential to life."

He says Kyoto requires that Canada make significant cuts in emissions, while countries like Russia, India and China face less of a burden.

Under Kyoto, Canada was required to reduce emissions by six per cent by 2012, while economies in transition, like Russia, were allowed to choose different base years. As developing nations, China and India were exempted from binding targets for the first round of reductions.

"Kyoto is essentially a socialist scheme to suck money out of wealth-producing nations," Harper's letter reads.

He said the accord would cripple the oil and gas industries, which are essential to Newfoundland, Nova Scotia, Saskatchewan, Alberta and British Columbia.

He wrote in the letter that he would do everything he could to stop Chrétien from passing the Kyoto agreement.

"We will do everything we can to stop him there, but he might get it passed with the help of the socialists in the NDP and the separatists in the BQ [Bloc Québécois]."

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

In recent weeks, Harper has spoken strongly about the environment, saying he will dramatically revamp his minority government's much-criticized clean air act.

His comments come as public-opinion polls indicate the environment has become the number one issue among Canadians.

Liberal MP Mark Holland told the Canadian Press on Tuesday that the leaked letter shows that Harper isn't actually committed to climate change.

"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," Holland said.

"But no one is buying it."

When the Kyoto Protocol went into effect Feb. 16, 2005, 141 countries had ratified it, including every major industrialized country, except the United States, Australia and Monaco. Monaco ratified the accord in February 2006.

With files from the Canadian Press