COPENHAGEN/OSLO - U.S. President Barack Obama urged world leaders on Thursday to break the deadlock at climate change talks in Copenhagen, even though many nations accused the United States of lacking ambition.

Accepting his Nobel Peace Prize in neighbouring Norway, Obama warned of dire consequences if the world did nothing to curb rising carbon emissions from burning fossil fuels and deforestation which scientists say are heating up the atmosphere.

The world must come together to confront climate change, Obama said in his Nobel acceptance speech. There is little scientific dispute that if we do nothing, we will face more drought, famine and mass displacement that will fuel more conflict for decades, he added.

The December 7-18 Copenhagen talks are meant to agree on the outlines of a tougher climate pact to expand or replace the existing Kyoto Protocol from 2013. But they have become bogged down over who should curb their emissions, who is most responsible and who should pay.

The talks are expected to deliver agreement on an initial fund of around $10 billion (6.1 billion pounds) a year until 2012 to help poor nations to fight climate change and make their economies greener. But developing countries believe that emissions cuts promised by rich nations, especially the United States, are far too low.

Tiny Tuvalu, a cluster of low-lying Pacific islands, brought part of the talks to a standstill on Thursday by insisting on its proposal for Copenhagen to deliver a legally binding treaty.

The main plenary sessions were suspended for consultations, although delegates continued holding side-meetings.

RISING SEAS

Tuvalu, which fears being washed off the map by rising seas, insisted the conference must consider its proposal for a legally binding treaty on far deeper cuts in greenhouse gas emissions than the United States and other rich nations are offering,
Tuvalu's stance exposed rifts between developing nations, many of which would be required to do much more under its proposal to curb greenhouse gas emissions. Nations including India and China spoke out against Tuvalu's plan.

Most other nations reckon Copenhagen can agree only a political text with legal texts to be worked out next year.

Rich nations' emissions cuts targets remain a major sticking point in the talks. Poorer nations blame industrialised countries for most of the greenhouse gas pollution in the air and say they must make deep cuts.

The United States has offered a provisional target of 17 percent below 2005 levels -- equal to a 3 percent cut from 1990 levels while the European Union has pledged a cut of 20 percent below 1990 levels that could be raised to 30 percent if others also act.

China, Brazil and small island states all say the pledge is far too modest.

The U.N.'s top climate change official, Yvo de Boer, said developed countries would have to deepen planned emission cuts to a range of 25 to 40 percent below 1990 levels, as outlined by a U.N. climate panel.

That for me is the goal, de Boer told Reuters. Offers so far from rich nations total about 14 to 18 percent below 1990 levels.

Many countries have come here with initial offers for targets indicating there is flexibility in the numbers, he said. Whether that is achieved or not depends first of all on a discussion within the group of major developed countries.

GREEN LOANS
In a bid to break the impasse on longer-term climate finance, Hungarian-born financier George Soros said green loans to poor nations backed by International Monetary Fund gold reserves could total $100 billion.

I've found a way for someone else to pay ... to mobilise reserves that are lying idle, Soros told Reuters on the sidelines of the talks that will end with a summit of 110 world leaders meant to agree a new climate pact.

This $100-billion fund I think could just turn this conference from failure to success, he said, admitting there were several legal and practical hurdles to unlocking the cash.

Poor nations want rich countries to spend 1 percent or more of their national wealth on emissions cuts in the developing world, or at least $300 billion annually, and about double the highest estimates by industrialised countries.

The U.N. climate panel says global greenhouse gas emissions must peak by 2015 and then start to decline to avoid run-away climate change through rising temperatures.

The British Met Office said on Thursday global temperatures are likely to rise next year to the highest levels in over 150 years from human activity and the El Nino phenomenon.

The latest forecast from our climate scientists, shows the global temperature is forecast to be almost 0.6 degrees Celsius above the 1961-90 long-term average, the Met Office said in a statement.

(Additional reporting by Emma Graham-Harrison in Copenhagen and Kwok W. Wan in London; Writing by David Fogarty, editing by David Stamp)