Several countries have criticised Canada for formally withdrawing from the Kyoto Protocol on climate change.
A spokesman for France's foreign ministry called the move "bad news for the fight against climate change", a sentiment echoed by other officials.
Peter Kent, Canada's minister of the environment, has said the protocol "does not represent a way forward".
The move, which is legal and was expected, makes Canada the first nation to pull out of the global treaty.
A spokesman for China's foreign ministry told reporters that the decision was "regrettable and flies in the face of the efforts of the international community", Reuters news agency reported.
The protocol, initially adopted in Kyoto, Japan, in 1997, is aimed at fighting global warming. Through the agreement, countries like China and India take voluntary, but non-binding steps to reduce their carbon emissions.
Japan's own environment minister, Goshi Hosono, urged Canada to stay in the protocol.
But that will not happen, Mr Kent said. "Kyoto, for Canada, is in the past, and as such we are invoking our legal right to withdraw from Kyoto," Mr Kent said.
He said he would be formally advising the United Nations of his country's intention to pull out.
He said meeting Canada's obligations under Kyoto would cost $13.6bn (10.3bn euros; £8.7bn): "That's $1,600 from every Canadian family - that's the Kyoto cost to Canadians, that was the legacy of an incompetent Liberal government."
Despite that cost, greenhouse emissions would continue to rise as two of the world's largest polluters - the US and China - were not covered by the Kyoto agreement, Mr Kent said.
"We believe that a new agreement that will allow us to generate jobs and economic growth represents the way forward."
Mr Kent's announcement came just hours after a last-minute deal on climate change was agreed in Durban
Talks on a new legal deal covering all countries will begin next year and end by 2015, coming into effect by 2020, the UN climate conference decided.
Some countries, including India, were worried that the first nation to formally remove itself from the binding Kyoto agreement would jeopardise the future conferences.
For low-lying island nation Tuvalu, most at-risk for rising sea levels, the withdrawal was more personal.
"For a vulnerable country like Tuvalu, its an act of sabotage on our future," Ian Fry, Tuvalu's lead negotiator told Reuters. "Withdrawing from the Kyoto Protocol is a reckless and totally irresponsible act."
Australia's lead delegate, Minister of Climate Change Greg Combet has defended Canada's decision.
"The Canadian decision to withdraw from the protocol should not be used to suggest Canada does not intend to play its part in global efforts to tackle climate change," a spokesman told the Sydney Morning Herald.
Mr Kent said that Kyoto was a "dated document" but said "there was good will demonstrated in Durban, the agreement that we ended up with provides the basis for an agreement by 2015".
Though the text of the Durban agreement "provides a loophole for China and India", the Canadian minister said, it represents "the way forward".
Canada's previous Liberal government signed the accord but Prime Minister Stephen Harper's Conservative government never embraced it.
Canada declared four years ago that it did not intend to meet its existing Kyoto Protocol commitments and its annual emissions have risen by about a third since 1990.
Canada's withdrawal from Kyoto was not unexpected. In early December, Canada's The Globe and Mail looked at the likely costs or penalties of either failing to meet the 2012 Kyoto targets or withdrawing from the protocol. "The question which remains is whether the effect on Canada's international reputation would be greater as a result of withdrawal or non-compliance," Andrew Leach writes.
A CBC analysis argues that the original Kyoto protocol did its job, if only in the narrow sense of reducing the emissions of signatories. However, at the time same emissions levels in other countries grew. Robert Sheppard writes that Canada set naive set targets last time and by failing to live up to them has damaged its position.
"It's a legitimate argument: China needs to step up." he says. "But how do you make it with a straight face when you haven't come anywhere close to meeting your own international obligations and you also want to turn around and sell China as much oil sands petroleum as it is willing to take?"
Globe and Mail opinion columnist Margaret Wente dismisses the Durban talks as "absurd" and says climate change conferences are more about power and money and the opportunity for growing economies to "extract billions" from rich countries.
Meanwhile, Craig McInnes at the Vancouver Sun sees the Kyoto withdrawal as part of a larger abandonment by the Canadian government on the climate issue, and worries that while his fellow citizens say they care about the environment, they lack the will as consumers and citizens to make significant changes.