BUENOS AIRES, Argentina - The United States showed no signs of budging in its opposition to the Kyoto protocol Monday as U.N. climate change talks began, a month after President Bush's reelection and Russia's ratification of the agreement.

It is a fantasy to try to mitigate climate change without the participation of the United States.

Juan Carlos Villalonga, director of campaigns at Greenpeace Argentina

The U.S. government said it had "chosen a different path" from Kyoto, but vowed to work against global warming by slowing greenhouse gas emissions, investing in climate science and technology and cooperating internationally.

Bush withdrew in 2001 from the 128-nation Kyoto protocol, which seeks to cut carbon dioxide emissions by five percent from 1990 levels by 2012. He argued it was too expensive and wrongly excluded developing nations.

Of the large industrialized countries, only the United States and Australia have refused to join the U.N. effort. But they account for around one-third of global emissions. The Australian government says ratifying Kyoto would hike power prices and cost the country jobs.

Scientists predict the rise in temperatures will accelerate melting glaciers and polar ice caps, leading to a rise in sea levels, extreme weather like heat waves, the spread of tropical diseases and the collapse of forests, coral reefs and farming.

"Efforts to address climate change will only be sustainable if they also serve a larger purpose of fostering prosperity and well-being for citizens around the globe," Harlan Watson, alternate head of the U.S. delegation, told the Buenos Aires conference to the parties, known as COP 10.

Russia's ratification has created the most optimistic mood in years among environmentalists since it allows Kyoto to go into effect in February with a seven-year delay.

KYOTO ENTERS INTO FORCE

"The fact that the Kyoto protocol enters into force really gives much more strength to this debate," Joke Waller-Hunter, executive secretary for the U.N. framework convention on climate change, told Reuters.

No major targets are expected from Buenos Aires. Rather, it is an opportunity for countries to begin discussing a timetable to define how much climate change the world can handle.

The conference has drawn 6,000 delegates from 194 countries, and environmental ministers from 80 countries will meet in the final days of COP 10, from Dec. 15-17.

But the United States' refusal to sign hangs over the 12-day meeting.

"It is a fantasy to try to mitigate climate change without the participation of the United States," said Juan Carlos Villalonga, director of campaigns at Greenpeace Argentina.

Miguel Rementeria, an Argentine environmental activist, said he harbors no hopes of a shift in U.S. policy.

"The big businesses that back Bush don't want it (Kyoto) and that won't change," Rementeria said.

To drive home the point of climatic changes, Greenpeace built a giant ark on Buenos Aires' main avenue where some 2,000 people lined up Monday to take temporary refuge.

But even Kyoto's backers say its provisions are not enough to reverse global warming and it is essential to get developing nations -- notably China, India and Brazil -- on board.

The Buenos Aires talks will touch on the participation of these countries in curbing emissions after Kyoto runs out in 2012. China, now an industrial powerhouse, is the second biggest producer of emissions behind the United States but is much lower on a per capita basis.

The European Union and some environmental groups want to limit any global temperature rise to 2.0 Celsius (3.6F). Temperatures have risen by 0.6 C since the late 1800s.

© Copyright 2004 Reuters Ltd

###