THE HAGUE, Netherlands - In a shift that is likely to brighten prospects for a global warming treaty, American negotiators at talks here have said the United States would be willing to limit its use of forest projects to reach its target for reducing heat-trapping greenhouse gases.
The new stance, signaled in the face of mounting criticism from Europe and private environmental groups, came this weekend, halfway through a contentious two-week session aimed at writing the fine print for the treaty, called the Kyoto Protocol.
The treaty was worked out by more than 170 nations in Japan in 1997. If ratified, it would commit three dozen industrialized nations to reduce their combined greenhouse-gas releases by 2010 to at least 5 percent below what their emissions were in 1990, with each country taking a unique target depending on its emissions.
The rules and means to achieve cuts were not resolved. This session, called the Sixth Conference of the Parties, was intended to produce the denouement.
Many disagreements in these pivotal negotiations have focused on the role of forests as "sinks," in which carbon dioxide, a warming gas flooding the atmosphere from the burning of fossil fuels and forests, is removed by trees, which store the carbon in wood and soil.
The United States, by far the largest emitter of greenhouse gases, calculated last summer that its vast forests, by absorbing up to 300 million tons a year of carbon dioxide, could help it get halfway to its pledged target under the treaty, reducing emissions by 2012 to 7 percent below where they were in 1990. It also wanted to get credit for paying for forest-protection and tree-planting projects in other countries.
But Europe, too crowded to take advantage of forests, and many private environmental groups say crediting forest growth would allow the United States and other large, forested countries to meet their targets without undertaking the much harder, and potentially more costly, task of reducing greenhouse gases at source: mainly tailpipes and smokestacks.