KYOTO, Japan - Representatives of 150 nations are converging on this city of ancient temples to negotiate a 21st-century insurance policy for the planet, a deal to control energy use as a first installment on protecting the atmosphere against global warming.
The talks are highly technical and complex, the politics challenging.
"There are times when only an act of courage can spur progress in world affairs," U.N. Secretary-General Kofi Annan said in a statement wishing the conference success as it opens Monday.
Chief U.S. negotiator Stuart E. Eizenstat predicted a "moveable feast" of hard-fought compromises.
If successful, the 10 days of negotiations could lead in a decade or so to shifts toward new-technology automobiles and fuel-saving driving habits, away from coal-powered electricity plants, and toward new farming and forestry practices.
Such controls over carbon dioxide and other "greenhouse" gases could, in turn, begin to forestall the damaging rises in temperatures, sea levels and severe weather that scientists predict from global warming.
But almost every feature of this 21st-century plan - including who should act, how and when - is in dispute. And powerful opposition has developed against early action, especially among oil-producing countries and U.S. coal, oil and other interests likely to be hurt.
Industry lobbyists are among the thousands of diplomats, scientists, environmentalists and journalists assembling in Japan's old capital in the midst of unusually mild weather that has Japanese fretting that "global warming" may ruin their Winter Olympics in February in Nagano.
But the vagaries of any day's or month's weather cannot be attributed confidently to global climate change. And this imprecision among scientists has weakened the hand of those trying to combat the phenomenon.
At the 1992 Earth Summit in Brazil, the world's nations signed a Climate Change Treaty that, because of U.S. opposition, set only a voluntary goal: reducing greenhouse gas emissions to 1990 levels by 2000.
It soon was clear most countries would miss that goal, and in 1995 governments agreed to toughen the treaty by negotiating legally binding targets and timetables. Several preliminary rounds of talks laid the groundwork for final discussions here over a treaty protocol.
The underlying principle of climate change is undisputed: Carbon dioxide, methane, nitrous oxide and a few other gases, mostly from fuel combustion, are transparent to incoming sunlight but trap the heat that Earth emits back to space.
In 1995, as atmospheric concentrations of carbon dioxide stood about 30 percent higher than in pre-industrial times, a U.N.-sponsored network of climate scientists issued a pivotal report, declaring global warming was under way and man was apparently partly to blame. Global average temperatures had risen by up to 0.6 degrees Celsius (1 degree Fahrenheit) in the past century.
The scientists predicted growing emissions would boost temperatures an additional 1 and 3.5 degrees Celsius (2 to 6 degrees Fahrenheit) by 2100, and raise sea levels 15 to 95 centimeters (6 to 37 inches), inundating islands and shorelines, because the warmth would expand ocean volume and melt glaciers.
The warming also would shift climate zones abruptly and make regional weather wetter, drier and generally more turbulent, they said.
Critics have seized on the uncertainties of the projections to resist early action.
"There's a danger of having policy driven by the worst-case scenario," complained the American Petroleum Institute's William O'Keefe, chairman of the Global Climate Coalition, a U.S. industry group that contends emission controls will throw hundreds of thousands of Americans out of work.
Environmentalists counter than even a degree more warming could be damaging - flooding much of low-lying, overcrowded Bangladesh, for example.
And the worst-case scenario could be calamitous for everyone, said Michael Oppenheimer of the U.S. Environmental Defense Fund.
"In the face of uncertainty, what do you do?" he asked. "Some are willing to take a gamble."
Key issues confronting the negotiators:
- Proposals to reduce industrial nations' emissions range from an ambitious 20 percent cutback below 1990 levels by 2005, to the low-end U.S. plan for reducing emissions to, but not below, 1990 levels by 2012. The Clinton administration says its plan would mean reductions of more than 25 percent in what U.S. emissions otherwise would be.
- Washington is pushing hard for a system of trading "emissions permits," so that a utility in Chicago could, in effect, continue burning coal by buying a permit from a country, such as Poland, where it might prove cheaper to cut emissions by converting to more climate-friendly natural gas.
- The U.S. team also is looking for ways to commit developing countries to emissions reductions.
The industrial world, largely responsible for the carbon buildup, agreed in 1992 to exempt poorer nations from cutbacks. But the U.S. Senate, fearing economic competition from China and others free to burn cheap coal, threatens to kill any treaty protocol that does not cover developing nations.
Eizenstat said his negotiators are working to extend commitments to a "critical mass" of developing countries. Wealthier U.S. friends, such as South Korea and Argentina, might opt to adhere to targets.
The protocol won't dictate how countries should cut back on emissions. But recommended solutions will include conversion to "hybrid" automobiles that phase out the internal combustion engine; improved mass transit; phasing out power plants relying on high-carbon coal; introducing new feeds for cattle, which emit major amounts of methane; and better protection for forests, which absorb carbon dioxide.