When the Kyoto Protocol took effect in February, many hailed the event as a significant political start in a long-term fight against global warming - despite President Bush's declaration in 2001 that the US no longer would participate.
Monday, delegates are meeting in Montreal to confront a new question: What will "son of Kyoto" look like once the curtain falls on the agreement's first commitment period, which runs from 2008 to 2012?
The answer is critical, analysts say. The pact requires its industrial-country members to cut emissions of heat-trapping greenhouse gases by an average of 5.5 percent during the first period. To do that, these countries will rely heavily on the protocol's economic tools - from building green projects in developing countries to trading carbon "credits" as if they were pork bellies - in addition to any direct emissions reductions they may make. But investments in these will vaporize unless businesses and investors are confident that they will be available beyond 2012.
Moreover, by design, the Kyoto Protocol fails to include in its regime of targets and timetables developing countries such as China and India - substantial sources of the industrial greenhouse gases that many scientists say are warming the planet at a troubling rate. These countries must be brought on board in any post-2012 regime, many specialists say, as must the United States, which is the industrial world's single largest source of greenhouse gases. Without the US and Asia's emerging industrial giants, experts hold out little hope that the world can stabilize greenhouse-gas concentrations in the atmosphere at levels that forestall what the UN has dubbed "dangerous" climate change.
"Global warming is no longer a 'what if.' Changes are beginning to happen," says Michael Oppenheimer, who heads the Program in Science, Technology, and Environmental Policy at Princeton University in Princeton, N.J. "This is the critical decade."
The two-week meeting here actually represents two meetings in one. It's the 11th annual gathering under the 1992 UN Framework Convention on Climate Change, which relies on voluntary actions and established the principle that as the largest polluters collectively, industrial countries had to make the first move to curtail emissions. The US Senate ratified this treaty.
The main focus for many delegates here lies in the first "meeting of the parties" that ratified the Kyoto Protocol. MOP-1, as it's formally known, will try to iron out some of the kinks in its economic tools. For example, the UN announced recently that the board governing the so-called "clean development mechanism" projects had approved two hydroelectric dams for Honduras. But critics say that the CDM office is understaffed and burdened by red tape.
But its main job is to begin outlining a script for the protocol's sequel acceptable to China, India, and perhaps, the US.
Some of the ideas people are floating for a more-flexible regime after 2012 would appear to vindicate Mr. Bush's approach, at least on the surface.
"I think it's safe to say there will be no softening of the US position" regarding Kyoto, says Ray Kopp, a senior fellow at Resources for the Future in Washington.
He notes that European nations, led by British Prime Minister Tony Blair, "are suggesting that ... legally binding targets are not the wave of the future and that voluntary goals and a greater reliance on technology are the proper path. This sounds an awful lot like the Bush administration."
Yet he and others point out that Mr. Blair's message is more subtle than it first appears. Many of the EU's ideas for a post-2012 regime are aimed at attracting developing countries. This might include targets for an economy's "carbon intensity," rather than for emissions per se. Ideas also include setting mandatory targets for one or two specific economic sectors, rather than for the economy as a whole.
Still, under Mr. Blair's formulation, industrial countries would continue to use mandatory targets-and-timetables, notes Phil Clapp, president of the National Environmental Trust, based in Washington.
Meanwhile, the US has been promoting an all-volunteer force through its Asia-Pacific Partnership for Clean Development and Climate, which focuses on carbon intensity and embraces many of the broader Framework Convention goals. It involves China, India, Australia, Japan, and South Korea, and is seen by some as an attempt to give Asia an alternative to even a more-flexible Kyoto process.