"We have completed our Montreal marathon, although the road before us remains so long. We are going to reconcile humanity with its planet," announced Canadian Environment Minister Stephane Dion, bringing down the gavel on a 13-day meeting high on drama and long on exhaustion.

The conference of the UN Framework Convention on Climate Changewas tasked with charting the next steps in curbing emissions from fossil fuel gases that scientists say are trapping heat from the Sun and disrupting Earth's fragile climate system.

After often-bitter negotiations, members of the Kyoto Protocol agreed to start talks from next May on how to cut their emissions beyond 2012, when the treaty's present "commitment period" expires.

A year from now, the chief negotiating positions of the big players are likely to have emerged, although the negotiations will probably last several years or even longer.

The agreement was a resounding show of support for a treaty that has been in deep trouble since March 2001 when the United States, the world's biggest carbon polluter, walked away from it.

The accord also gave a powerful boost to the fledgling market in carbon emissions, a key mechanism set up under Kyoto to encourage cuts, and troubled recently by fears of collapse beyond 2012.

And it built a bridge between the Kyoto members and the United States by agreeing to a "dialogue" on how to make long-term cuts in greenhouse gas pollution.

"What we have is a highly successful outcome... a hugely important day in the global effort to tackle climate change," said British Environment Secretary Margaret Beckett, whose country is current EU chair.

"(It was) important not least because the whole global community, including some of the key players such as the United States, India and China, have agreed to work together through the United Nations process to examine the way forward."

The UNFCCC said more than 40 decisions were made during the Montreal meeting, which it described as "one of the most productive UN climate change conferences ever."

Environmentalists heaped scorn on the hardline tactics taken by Russia and America and declared that Kyoto, which took its first steps only last February after years to agree its rulebook and secure ratification, now had a bonny future.

"The Kyoto Protocol is stronger today than it was two weeks ago," said Greenpeace International's Bill Hare. "The historic first meeting of the parties has acknowledged the urgency of the threat that climate change poses to the world's poorest people, and eventually, to all of us."

The "dialogue" on long-term action on climate change is vaguely worded and, in deference to the United States, has no binding obligations or specific goals.

But if it works, it could break US isolationism on climate change.

Green campaigners hope that by involving the United States more closely in a multilateral process, it will be easier for Washington to come back into the Kyoto fold after US President George W. Bush leaves office in January 2009.

Greenhouse gases are the carbon byproduct of burning oil, gas and coal.

Billions of tonnes are released into the air each year, trapping heat from the Sun and causing what scientists say are early signs of climate change -- disruption of rainfall patterns, melting glaciers and polar sea ice and, possibly, the 2005 Atlantic hurricane season, the worst on record.

Even if all the present Kyoto goals are met, industrialised countries will have trimmed output of greenhouse gases by just one or two percent by 2012 as compared to a 1990 benchmark.

Tackling the problem will thus require a broader, longer-term approach, bringing in the United States, the world's No. 1 polluter, as well as China, which is the second biggest contributor to greenhouse gases, and maybe Brazil and India too.

This is politically very tough, not just because of Bush's fierce opposition to the Kyoto format, which Washington sees as costly for the oil-dependent US economy.

Developing countries at present lie outside the requirement to make specific cuts in emissions. They argue that rich countries are most to blame for global warming because of their unbridled burning of carbon fuels in the 20th century.

Another task will be switch economies from dirty fossil fuels to cleaner energy sources.

That is the biggest challenge of all, because oil, gas and coal have a tight grip on the world's energy market, enjoying a big price advantage and political clout over new, cleaner alternatives such as solar, wind, hydrogen and biofuels.

The Montreal meeting, gathering 8,700 ministers, senior officials, green campaigners, scientists and businessmen, was to have ended late Friday.

But it ended at dawn on Saturday, in an mixture of euphoria and exhaustion, after the United States battled on the "dialogue" question and Russia raised a last-minute roadblock on launching the post-2012 Kyoto talks. Both backed down, receiving in exchange a face-saving textual compromise.

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