Canada is being "opportunistic" in its stance on carbon emissions reductions, the head of the Nobel Prize-winning climate science panel said on Thursday.
Canada has said emissions reductions targets should apply to all major emitters, including China and India, although past negotiations have agreed that industrialised countries bear greater responsibility for climate change.
"It is really an opportunistic position that they are taking," said Rajendra K. Pachauri, chair of the Intergovernmental Panel on Climate Change, which was jointly awarded this year's Nobel Peace Prize with former US vice president Al Gore.
Canadian Conservative Prime Minister Stephen Harper, whose government was elected last year, said in November that the 1997 Kyoto Protocol failed because it did not impose binding cuts on major developing emitting nations.
"This particular government has been a government of skeptics. They do not want to do anything on climate change," Pachauri said.
"The previous government had a very different approach" in its response to climate change, Pachauri said, referring to the earlier Liberal administration.
Canada had agreed under the Kyoto Protocol to reduce its CO2 emissions to 6 percent below 1990 levels by 2012, but emissions have risen by 35 percent.
The Canadian government has said the target, negotiated by the previous administration, is unattainable -- a turnaround that has shocked environmental groups.
In April, Canada's Environment Minister John Baird unveiled a plan to cut the country's emissions linked to global warming by 20 percent by 2020, based on current levels, and by up to 70 percent by 2050.
Baird said earlier this week that Canada was ready to accept national binding targets, "but if we're to be successful globally in fighting greenhouse gas emissions, that is not enough.
"We need countries like the United States, China and India to accept binding targets just as Canada is prepared to do," he said.
Environmentalists have criticised Japan and Canada for their positions at key climate talks on how to curb global warming taking place on the Indonesian island of Bali.
Japan has raised the idea of "pledges" rather than deeper binding cuts of carbon emissions from 2012 to succeed the commitments hammered out in the Japanese city of Kyoto a decade ago.
Pachauri defended Japan
"In relative terms Japan is an energy-efficient society. They have done a fair amount already so they have probably exhausted all the low-hanging fruit," he said.
"They have exhausted a number of the less expensive options and now if they have to reduce emissions they will have to move some of the more expensive ones. So I can understand their concerns."