Industrialized and developing nations were close to a deal this evening to start work on extending the Kyoto Protocol to fight global warming past 2012, but the United States resisted calls for new commitments to combat climate change.
On the final day of the UN conference on climate change, environmentalists said they were losing hope that the United States - the largest producer of heat-trapping greenhouse gases - would sign a separate agreement for all nations, not just Kyoto members.
Although the US is not one of the 157 countries that have subscribed to Kyoto, Canada wants a deal on open-ended talks among all countries about long-term cooperation on climate change.
Delegates said US climate negotiator Harlan Watson walked out of a session of talks overnight, saying host Canada's proposal for dialogue on long-term actions was tantamount to entering negotiations.
But European Union officials spearheading talks kept the door open. "Sixty years ago Winston Churchill told the US Congress the United States always does the right thing, after having exhausted all other options'," EU Environment Commissioner Stavros Dimas told a news conference.
"I think it will be very difficult for the United States not to join the dialogue that has almost unanimous support," he added. Regardless of US resistance, countries participating in Kyoto are meant to announce an agreement to launch negotiations next year for the second phase of the protocol.
This would give members seven years to negotiate and ratify accords by the time the first phase ends in 2012. President George W. Bush pulled out of Kyoto in 2001, arguing that mandatory cuts on emissions from fossil fuels would hamper growth and job creation.
Washington prefers its own approach to stem global warming, mostly by investing heavily in technology. Many here had hoped that the United States' resistance would be broken by this year's extreme weather events, particularly Hurricane Katrina's destruction of New Orleans. Scientific evidence suggests global warming might be behind recent devastating weather patterns.
Former US President Bill Clinton, who supported Kyoto but failed to convince US lawmakers, will enter the fray with an appearance on the sidelines of the conference. US head delegate Paula Dobriansky denied Mr Clinton's presence would be a problem for Washington.
"Public events...such as the one involving President Clinton are useful opportunities to hear a wide range of views on global climate change," she said. Environmentalists have urged the European Union - the leader in the process - to move ahead without Washington, even though Bush agreed at this year's G8 summit in Gleneagles to advance at Montreal.
"The brakes are being released, the process is moving forward," said Bill Hare, climate policy director at Greenpeace, of advances under Kyoto.
"This week we've seen some historic progress in the global response to climate change." Under Kyoto, some 40 industrialized nations agreed to cut emissions in 2008-12 by over 5 per cent from 1990 levels. But most countries agree that deeper and more long-term cuts will be needed to avoid climate chaos in coming decades.
There is also pressure to draw in developing giants like China and India, which were not included in the first phase of commitments and whose fast-growing economies rely heavily on dirty energy. Those countries steadfastly reject emissions curbs, but could benefit from the conference's long-term agreements to help them develop cleaner technology.