OSLO/LONDON - A summit of world leaders has dimmed hopes for a strong new U.N. climate pact to replace the Kyoto Protocol in Copenhagen in December, with details looking ever more likely to be left for 2010.

But climate change experts and observers also refused to focus on the negative, noting that many countries struggling with recession were likely to make concessions only at the last moment.

At the one-day U.N. summit Tuesday, leaders spoke strongly of a need for action to combat climate change but made few new pledges of domestic action. China won praise for outlining curbs on its rising emissions for 2020.

Leaders want to signal a willingness to act, but everyone is in this game of chicken, said Susanne Droege, of the German Institute for International and Security Affairs.

The good news (from Copenhagen) would be to have an international carpet laid out for further steps, she said.

Chinese President Hu Jintao said that China would slow the growth of its emissions by setting an unprecedented goal to curb by a notable margin the amount of carbon dioxide emitted per dollar of gross domestic product by 2020 against 2005.

U.S. President Barack Obama, facing a domestic battle over healthcare reform, urged global actions to slow climate change to avoid risks of irreversible catastrophe. But he stopped short of announcing new domestic measures to tackle the problem.

Nick Mabey, head of the E3G climate think-tank in London, said that the summit indicated that climate change would not go away as a top issue but that action was needed now. The idea that's terribly dangerous is to delay Copenhagen as a decision point, he said. The pressure that's building up is the only way to get international action.

Pressure is building for governments to show what they are willing to do, but time is fast running out. The world agreed in Bali, Indonesia, in 2007 to work out a new pact on December 7-18 in Copenhagen and negotiations next resume next week in Bangkok.

The U.N. Climate Secretariat has said Copenhagen needs at a minimum to agree steps including deep 2020 cuts in emissions by developed nations, new actions by developing nations to curb their rising emissions, and ways to raise funds.

But it says that a lot of details, such as exactly how to raise money and how to share it out, can be left for later. It has suggested $10 billion on the table in Copenhagen as a sign of good faith by rich nations.

Governments plan agreement in 2009 to give good time for ratification before the existing Kyoto Protocol's first period runs out at the end of 2012. Kyoto binds developed nations to cutting emissions but does not demand curbs by developing states.

WHO WILL PAY?

The world is split over how to divide up the burden of cuts in greenhouse gases between rich and poor nations and on how to raise billions of dollars to help developing nations fight global warming.

So far, rich nations have offered cuts in emissions that average 11-15 percent below 1990 levels by 2020. Poor nations want cuts of at least 40 percent to avert the worst of climate change.

The fact that the New York summit didn't bring any signs of significant steps (toward steep cuts in emissions) is a very worrying sign, said Johan Rockstrom, director of the Stockholm Resilience Center. He said China was the main exception.

China has overtaken the United States as top emitter of greenhouse gases projected by a U.N. panel of scientists to stoke ever rising sea levels, droughts, wildfires, a spread of some diseases or more powerful cyclones.

This is significant and shows China's seriousness about acting on climate change said Jennifer Morgan, the climate program director of the World Resources Institute in Washington.

The major missing piece now is action from the United States, she said.

Leaders of the Group of 20 will meet in Pittsburgh on Thursday and Friday, but little progress is expected on finding cash to help developing nations with climate finances.

China Barack obama Climate change Global warming