WASHINGTON - On the eve of critical negotiations on global warming, President Clinton on Saturday said the United States is committed to work with other nations in crafting rules that will provide a cost-effective way to curtail heat-trapping pollution of the atmosphere.
Clinton released a scientific analysis that he said ''paints a sobering picture of the future'' if climate change is not addressed and ''makes clear that this projected warming threatens serious harm to our environment and to our economy.''
''The scientific consensus is clear. The earth is warming and there is strong evidence that human activity is part of the reason why,'' said Clinton in remarks broadcast over the Internet.
More than 160 countries that crafted the Kyoto climate treaty in 1997 begin two weeks of intense negotiations next week in the Netherlands on how to implement the accord, which calls for industrial nations to cut heat-trapping greenhouse gases by 5.5 percent over the next decade.
''If we don't have significant progress ... we will have set back substantially the ability of the nations of the world to meet their (Kyoto emission) targets,'' Undersecretary of State Frank Loy, who will head the U.S. delegation, said in an interview.
Clinton also urged Congress to enact new laws that would regulate the amount of carbon dioxide - the leading greenhouse gas - and three other pollutants coming from power plants. Legislation calling for controls of carbon emissions from power plants was introduced earlier this year, but never was seriously considered by lawmakers.
None of the industrial nations has ratified the Kyoto agreement. They are awaiting details on rules and policies for implementing the accord, including provisions that could significantly impact the cost of compliance.
The U.S. delegation is expected to take to the negotiations a detailed plan aimed at mitigating the cost for cutting greenhouse gases - mostly carbon dioxide from burning fossil fuels.
The package of proposals includes:
-Unfettered trading of emissions credits, so that a country may avoid reductions from its factories, power plants or motor vehicles by buying pollution permits from a country already meeting its Kyoto target.
-Broad use of the natural capacity of forests and agricultural lands to absorb carbon through tree planting and land management. U.S. officials estimate half of the U.S. Kyoto target might be met this way.
-A flexible policy on the kinds of energy technology, including nuclear power, that would qualify as credits for industrial countries if used in developing countries to cut greenhouse emissions.
''Achieving meaningful reductions (of greenhouse gases) is a very big assignment, and we ought to make it as easy or as cost-effective as possible,'' said Loy.
U.S. officials disputed criticism by many environmentalists that the American proposal may thwart real reductions in greenhouse gases. They maintain that the flexibility provisions sought by the United States in implementing the treaty will produce the most economic reduction of heat-trapping emissions.
''We are going over there seeking a treaty that has environmental integrity,'' said Assistant Secretary of State David Sandalow, a key U.S negotiator.
But many environmentalists argue the U.S. proposal amounts to massive ''loopholes'' that will make Kyoto treaty compliance cheap but produce little actual reductions of greenhouse gases - mainly carbon dioxide from burning fossil fuels - from U.S. industry, power plants and motor vehicles.
''These loopholes would make the treaty virtually irrelevant from an environmental standpoint,'' said Alden Meyer of the Union of Concerned Scientists, a Washington-based environmental advocacy group.
For example, he said, instead of U.S. industry cutting greenhouse emissions, it would be cheaper to buy pollution credits from Russia, where annual carbon emissions already are far below 1990 levels because of the country's economic collapse.
Likewise, U.S. negotiators acknowledge that more than half the 500 million metric tons of carbon reductions needed to meet the Kyoto target could be achieved if their negotiating partners were to accept the U.S. proposal on carbon-absorbing forests and agricultural lands.
These ''do-nothing tons'' of carbon reductions would be achieved without requiring additional land management or a greater reduction in carbon put into the air, but they would count against the Kyoto targets, said Jennifer Morgan of the World Wildlife Fund.
European negotiators are expected to demand that limits be set how much a country can depend on trading. Germany and France wants no more than half of the required emission reductions to come from trading.
''We are strongly opposed to that,'' said Sandalow. If the Europeans insist on capping trading credits, ''no deal is better than a bad deal.''
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On the Net: Kyoto Protocol: http://www.cnie.org/nle/clim-3.html
State Department: http://www.state.gov/www/global/global-issues/climate/index.html
United Nations Intergovernmental Panel on Climate Change: http://www.ipcc.ch/
Pew Center: http://www.pewclimate.org
Global Climate Coalition: http://www.globalclimate.org
Energy Department: http://www.eia.doe.gov
Environmental Protection Agency: http://www.epa.gov/globalwarming/