Liberal Leader Stephane Dion is calling on Prime Minister Stephen Harper to reaffirm Canada's commitment to the Kyoto Protocol.
Dion tabled an opposition motion to that effect on Thursday. Earlier in the week a five-year-old letter surfaced in which Harper referred to the mechanism for fighting climate change as a money-sucking socialist scheme.
Dion's motion urges Parliament to acknowledge that there is "overwhelming scientific evidence" that global warming has been brought on by human activity.
It also asks the government to honour the Kyoto goals set under the previous Liberal government -- a set of targets for reducing greenhouse gas emissions that the Tories have said are unattainable.
The motion comes as Environment Minister John Baird prepares to attend a climate change conference in Paris.
Dozens of international delegates have gathered at the conference, where officials have approved a long-anticipated Intergovernmental Panel on Climate Change report that will say global warming is "very likely" caused by human activity.
Dion, a former Liberal environment minister, said Harper has attempted to "paralyze" previous international efforts by refusing to cooperate with global efforts.
"Can the prime minister assure us that he is not sending his minister to another United Nations conference to ... block international efforts to fight climate change?" Dion asked during question period in the House of Commons on Thursday.
Dion has been skeptical of Harper's apparent shift towards making the environment a priority.
"Canadians are not fooled," Dion told the House. "They know that this prime minister has no commitment to fight climate change. His only motive is to prepare for an election."
Dion suggested Harper is responding to polls that indicate the environment has become a priority for voters.
Harper said on Wednesday that he supports the idea of a summit on global warming, which some United Nations delegates are calling for. Harper vowed Canada would attend such a summit, even though it hasn't been planned yet.
With files from The Associated Press
