Canada on Friday backed the US approach to major climate change talks in Paris, saying any carbon reduction targets agreed at the negotiations should not be legally binding.
The announcement by Environment Minister Catherine McKenna could irritate host nation France, which wants any deal to be enforceable.
That would be politically impossible for the administration of US President Barack Obama, however, since it is clear the Republican-dominated Congress would not ratify any treaty imposing legally binding cuts on the US.
"Everyone wants to see the US be part of this treaty," McKenna told reporters on a conference call before flying to Paris.
"There are political realities in the US ... they cannot have legally binding targets. We don't expect that the targets will be internationally legally binding," she said.
Signatories to a Paris agreement should agree to update their climate change goals every five years, she added.
US Secretary of State John Kerry told the Financial Times this month that any deal reached in Paris was "definitively not going to be a treaty". His remarks drew a stern response from French President Francois Hollande.
Senior officials from almost 200 nations are due to meet from November 30 to December 11 in the French capital, including new Canadian Prime Minister Justin Trudeau.
Earlier in the day, Trudeau said Ottawa would give C$2.65 billion ($1.98 billion) in aid to developing nations over the next five years to help fight the effects of climate change.
Trudeau leads a new Liberal government which took power this month promising to take a much more aggressive stance on the environment than an outgoing Conservative administration widely criticised for not doing enough to combat global warming.
The Conservatives had pledged to cut greenhouse gas emissions to 30 per cent below 2005 levels by 2030 but government figures show rising emissions mean even this goal looks out of reach.
While Trudeau will not provide a new greenhouse emissions target in Paris, he has committed to coming up with a goal with Canada's 10 provinces within 90 days of returning from the talks. ($1 = 1.3362 Canadian dollars)
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