The sixth Conference of Parties to the United Nations Framework Convention on Climate Change, or COP6, collapsed in failure last weekend. In retrospect, the failure of negotiations that focused on cutting fossil-fuel emissions -- which would have a powerful impact on economic development -- and involved 181 nations was the most likely outcome. That does not mean that no agreement is possible. Leadership and vision can make it happen. And the growing evidence of global warming shows that some sort of accord is desperately needed.

COP6 was supposed to approve rules to implement the 1997 Kyoto Protocol, the treaty designed to reduce the greenhouse-gas emissions that contribute to global warming. According to that agreement, global emissions of those gases must decline 5.2 percent below 1990 levels by 2012. The reductions are not uniform: Japan must cut its annual carbon-dioxide emissions by 6 percent from 1990 levels, the United States must trim them by 7 percent and the European Union by 8 percent.

The chief sticking point in the COP6 negotiations was the use of "sinks" -- forests, plantations and reservoirs that absorb carbon dioxide -- to count toward the emissions targets. The U.S., the world's single largest producer of greenhouse gases, responsible for 24 percent of global emissions, has sought liberal allowances for its forests, as well as for rules that permit trading of "credits" among nations. The U.S. position was supported by Japan, Canada and Australia.