MONTREAL -- A UN conference on global warming ended yesterday with a watershed agreement by more than 150 nations -- an unwilling United States not among them -- to open talks on mandatory post-2012 reductions in greenhouse gases.
The Bush administration, which rejects the emissions cutbacks of the current Kyoto Protocol, accepted a second, weaker conference decision, agreeing to join an exploratory global ''dialogue" on future steps to combat climate change. However, that agreement specifically ruled out ''negotiations leading to new commitments."
The divergent tracks did little to close the climate gap between Washington and the Kyoto supporters, which include Europe and Japan. But environmentalists welcomed the plan to negotiate ''second-phase" emissions cuts.
''The Kyoto Protocol is alive and kicking," said Jennifer Morgan of the World Wide Fund for Nature.
Before bringing the two-week conference to a close in snowy Montreal, conference president Stéphane Dion told delegates, ''What we have achieved is no less than a map for the future, the Montreal Action Plan."
But Dion, Canada's environment minister, later acknowledged to reporters, ''I would prefer to have the United States in Kyoto."
The Montreal meeting was the first of the annual climate conferences since the Kyoto Protocol took effect last February, mandating specific cutbacks in emissions of carbon dioxide and five other gases by 2012 in 35 industrialized countries.
A broad scientific consensus agrees that these gases accumulating in the atmosphere, byproducts of automobile engines, power plants, and other fossil fuel-burning industries, contributed significantly to the past century's global temperature rise of 1 degree.
Continued warming is melting glaciers worldwide, shrinking the Arctic ice cap, and heating up the oceans, raising sea levels, scientists say. They predict climate disruptions in coming decades.
The United States is the world's biggest emitter of greenhouse gases, and the Clinton administration was instrumental in negotiating the treaty protocol initialed in 1997 in Japan -- a pact the Senate subsequently refused to ratify.
When Bush rejected Kyoto outright after taking office in 2001, he said its mandatory energy cuts would harm the US economy, and he protested that major developing countries were not covered.
The protocol's language required its 157 member nations by 2005 to begin talks on deeper emissions cuts for the next phase, which begins when Kyoto expires in 2012.
Environmental activists were pleased at agreements in such areas as how to quantify gas emissions and how to penalize nations that do not meet Kyoto targets.