| NUSA DUA, Indonesia
NUSA DUA, Indonesia The U.N.'s top climate change official hailed on Thursday moves by a U.S. Senate committee to fight climate change by capping greenhouse gas emissions in the world's top carbon emitter.
"That's a very encouraging sign from the United States," Yvo de Boer, head of the U.N. Climate Change Secretariat, said at 190-nation U.N. talks in Bali, Indonesia on trying to widen action against global warming.
It is the second piece of good news at the conference after Australia's new government ratified the Kyoto Protocol on Monday, leaving the United States as the only major industrialized nation outside the pact.
President George W. Bush opposes mandatory caps on emissions.
"Things are going well here," de Boer said of the December 3-14 negotiations that are seeking ways to bind all nations, including the United States and developing nations such as China and India, more tightly into a fight against climate change.
In Washington, the Senate Environment and Public Works Committee approved legislation outlining a cap-and-trade system for industry, power generators and transport. The bill is headed for debate in the full Senate.
"A parliament having a different opinion from a government is quite a common thing," de Boer said of opposition to Bush, a Republican. Many U.S. Democrats will visit Bali next week.
Bush has said Washington will support efforts to work out a new climate treaty by 2009, even though he says Kyoto would harm the U.S. economy and wrongly excludes goals for developing nations until 2012.
"The United States simply has to take a leadership role," Senator John Warner, a Virginia Republican and the bill's co-sponsor told the committee. "If we don't act, China and India will simply hide behind America's skirts of inaction."
Separately, more than 200 climate scientists from around the world urged delegates at the Bali talks to make deeper and swifter cuts to greenhouse emissions, mainly from burning fossil fuels.
They said governments had a window of only 10-15 years for global emissions to peak and decline, and that the ultimate goal should be at least a 50 percent reduction in climate-warming emissions by 2050.
"We appreciate this is a significant challenge for the world community," Professor Andy Pittman, from the University of New South Wales in Australia, told reporters in Bali.
"But it is what is required to reduce the risks of dangerous climate change, and that is what we are all trying to do here."
Professor Diana Liverman of Britain's Oxford University said the world was already seeing substantial impacts from global warming, but a warming of 2 degrees Celsius would have severe impacts in Africa, Australia, the polar regions and the Pacific Islands.
Outside the Bali conference centre, eight activists dressed as polar bears -- threatened by a melt of Arctic ice -- added a twist to the climate debate by holding banners reading: "Humans need help too".
Separately, the WWF conservation group said that 55 percent of the Amazon rainforest could be wiped out or severely damaged by 2030 by a "vicious feedback loop of climate change and deforestation".
It said the effects of warming could cut rainfall and aggravate current trends in farming, fires, droughts and logging in the world's largest tropical forest.
The Amazon's forests are a giant store of carbon dioxide -- trees soak up the main greenhouse gas as they grow and release it when they rot or are burnt.
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(Additional reporting by Alister Doyle in Bali, Deborah Zabarenko in Washington and James Grubel in Canberra; editing by Alister Doyle)