BANGKOK (Reuters) - Scientists and officials from across the world meet in Thailand this week for the first formal talks in the long process of drawing up a replacement for the Kyoto climate change pact by the end of 2009.
Around 190 nations agreed in Bali last year to start the two-year negotiations to replace Kyoto, which only binds 37 rich nations to cut emissions of greenhouse gases by an average of five percent from 1990 levels by 2012.
U.N. climate experts want the new pact to impose curbs on all countries, although there is wide disagreement about how to share out the burden between rich nations led by the United States and developing countries such as China and India.
No major decisions are likely from the Bangkok talks, which are intended mainly to establish a timetable for more rounds of negotiations culminating in a United Nations Climate Change conference in Copenhagen at the end of next year.
"The challenge is to design a future agreement that will significantly step up action on adaptation, successfully halt the increase in global emissions within the next 10-15 years and dramatically cut back emissions by 2050," said Yvo de Boer, head of the U.N.'s Climate Change Secretariat.
Although the negotiations are likely to be tough and tortuous, a series of U.N. climate change reports last year highlighted the need to curb emissions of greenhouse gases such as carbon dioxide that are driving global warming.
One report in particular said it was more than 90 percent certain that human actions -- mainly burning fossil fuels -- were to blame for changes to the weather system that will bring more heatwaves, droughts, storms and rising seas.
One major issue to be tackled is the reluctance of big developing nations such as India and China to agree to any measures that might curb their rapid industrialization.
Negotiators will also have to work out how to deal with the United States -- the only rich nation not to have signed up to Kyoto -- given that President George W. Bush will be leaving the White House after November's election.
Bush pulled the United States out of Kyoto in 2001, saying the pact would hurt the U.S. economy and was unfair since it excluded big developing nations from committing to emissions cuts.
The White House has since moderated its stance by saying the Bush administration would accept emissions targets if all other big emitters do as well based on their individual circumstances.
This has tempered the criticism of the Bush administration but green groups and many poorer nations say they don't expect much progress on a replacement climate pact until a new U.S. administration takes office in January 2009.
"I think the U.S. really has changed," de Boer told Reuters.
All three main presidential candidates are greener than Bush and back a cap-and-trade system to encourage business to curb carbon emissions.
The United Nations wants the new treaty to be in place by the end of 2009 to give companies and investors as much advance knowledge as possible of coming changes, and national parliaments time to ratify it before 2012, when Kyoto expires.
Additional reporting by Alister Doyle in Oslo; Editing by Michael Battye and David Fogarty