Delegates to a pivotal climate conference welcomed an Obama administration move Monday to regulate greenhouse gases under existing clean air law, but said they still expect more.
The announcement came as the two-week meeting of 192 nations opened with emotional appeals from those countries endangered by rising seas and other damage from climate change.
The finding by the U.S. Environmental Protection Agency would supplement the cap on carbon dioxide emissions being considered in the U.S. Congress, effectively raising the U.S. offer on emissions reductions in two weeks of hard bargaining in Copenhagen.
"The executive branch is showing what it can do, even while legislation is pending," Rajendra Pachauri, chairman of the U.N. scientific network on climate change, said of the EPA action. "It also sends a powerful signal to Congress. It shows a degree of resolve on the part of the president."
The conference climax will come when President Barack Obama and more than 100 other national leaders arrive for the final hours of talks next week. In preparation, Obama met with former Vice President Al Gore, a leading climate campaigner, at the White House on Monday.
Earlier in the day, the European Union had called for a stronger "bid" by the Americans, who thus far have provisionally pledged emissions cuts much less ambitious than Europe's.
The endgame in Copenhagen "will mostly be on what will be delivered by the United States and China," the world's two biggest greenhouse-gas emitters, European Union environment spokesman Andreas Carlgren told reporters. He said he would be astonished if Obama did not put more on the table.
Whether the prospect of EPA action will satisfy such demands _ and what China may now add to its earlier offer _ remains to be seen. And success in the long-running climate talks hinges on more than emissions reductions. Most important, it requires commitments of financial support by rich countries for poor as they cope with the impacts of a changing global climate.
"The clock has ticked down to zero. After two years of negotiations, the time has come to deliver," Yvo de Boer, the U.N. climate chief, said as he opened the conference in the chill and foggy Danish capital.
The conference president, Denmark's Connie Hedegaard, called it a last, best chance.
"Political will has never been stronger," she told delegates assembled in the Bella Center's cavernous plenary hall. "And let me warn you: Political will will never be stronger. This is our chance. If we miss it, it could take years before we got a new and better one. If ever."
Some 15,000 delegates, environmentalists, business lobbyists, journalists and others are gathered in the huge convention center for the pivotal talks, along with thousands more outside, planning protests, street theater and scholarly discussions. The colorful global show demonstrates that the future of the Earth's climate is the future of everyone, from Eskimos and Midwest farmers, to oil sheiks and African peasants.
As climate talks have dragged on for two decades, the planet has continued to warm, something scientists blame largely on carbon dioxide and other emissions from the burning of fossil fuel and other industrial, transport and agricultural sources. On Tuesday, the World Meteorological Organization is expected to announce that 2009 ranks as one of the warmest years on record, and this decade as the warmest.
Pachauri, the head of the Intergovernmental Panel on Climate Change, defended climate research in the face of a controversy over e-mails pilfered from a British university, which global warming skeptics say show scientists have been conspiring to hide evidence that doesn't fit their theories.
"The recent incident of stealing the e-mails of scientists at the University of East Anglia shows that some would go to the extent of carrying out illegal acts perhaps in an attempt to discredit the IPCC," he told the conference.
The focus in Copenhagen has fallen on individual countries' pledges of emission reductions, to be incorporated in some final agreement to succeed the Kyoto Protocol, whose modest emission cuts for 37 nations expire in 2012.
The EU has pledged an ambitious 20 percent reduction in gases by 2020, compared with 1990 levels, and 30 percent if other nations also aim high. Japan has offered a 25 percent cut against 1990, and Australia up to 25 percent.
After eight years of inaction under the Bush administration, Obama has offered to reduce U.S. emissions by about 17 percent by 2020 _ but against a later benchmark year, 2005. Compared with 1990, that's only a 3 percent to 4 percent cut. Obama's offer had to be provisional, pending action in Congress.
Before the conference, developing countries, exempt under Kyoto, made their own offers: China said it would, by 2020, reduce gases by 40 percent to 45 percent below "business as usual" _ that is, judged against 2005 figures for energy used versus economic output. India offers a 20 percent to 25 percent slowdown in emissions growth. Unlike industrialized nations, developing countries' targets are not expected to be made legally binding.
Environmentalists had urged that the U.S. EPA act on its own, without relying on congressional action, to regulate carbon dioxide, the most important greenhouse gas.
The EPA said that the scientific evidence surrounding climate change clearly shows that greenhouse gases "threaten the public health and welfare of the American people" and that the pollutants _ mainly carbon dioxide from burning fossil fuels _ should be regulated under the Clean Air Act.
"These long-overdue findings cement 2009's place in history as the year when the United States government began addressing the challenge of greenhouse-gas pollution," EPA Administrator Lisa Jackson said at news conference.
Any regulations are also likely to spawn lawsuits and long legal fights.
Business groups strongly oppose tackling global warming through the Clean Air Act, saying it is more rigid and costly than the bill before Congress.
U.S. Chamber of Commerce President and CEO Thomas J. Donohue said EPA regulations could lead to "a topdown command-and-control regime that will choke off growth by adding new mandates to virtually every major construction and renovation project."
The American Petroleum Institute, the main lobbying group for oil and gas companies, called it a political maneuver.
White House spokesman Robert Gibbs suggested the timing of the EPA announcement and the opening of the Copenhagen conference was coincidental _ "based on the fact that the first step" of a court-ordered regulatory process was being completed.
Nonetheless, the announcement was expected to enliven the debate in Copenhagen's closed-door meetings, as negotiators try to join a list of emissions pledges to commitments on financing for poorer countries, in final decisions setting the stage for a possible post-Kyoto treaty next year.
On financing, richer nations have expressed support for a three-year, $10 billion-a-year package to help poorer nations adapt _ with coastal protection, agricultural modification and other measures _ and to install clean-energy sources. The chief U.S. negotiator, Jonathan Pershing, reiterated that Washington would contribute its "fair share" to that package.
Poorer nations are expected to press for "fast-start" money, and for much higher amounts in the long term, along with a structure guaranteeing delivery, through aviation taxes or some other devices. Expert studies project that hundreds of billions of dollars a year, in public and private money, will be needed.
In some cases, domestic politics may still complicate governments' ability to meet their commitments on emissions. The carbon-capping bill is encountering tough opposition in the U.S. Senate. In India, opposition lawmakers walked out of the upper house of Parliament to protest the government's Dec. 3 offer to reduce emissions growth. A Communist lawmaker complained it would hurt India's poor.
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