Next year could be the warmest year on record, the Met Office said today as officials at UN talks in Copenhagen continued negotiations in a bid to secure a new deal to tackle climate change.
The forecast from climate scientists said a combination of man-made global warming and a weather pattern - known as El Nino - heating the Pacific Ocean would make it very likely that 2010 would be warmer than 2009.
This year is expected to be the fifth warmest on record.
But the researchers sounded a note of caution, warning that a record year in 2010 is not a certainty, especially if the current El Nino declined or there was a large volcanic eruption.
The latest figures were unveiled as more than 1,700 scientists, led by the Met Office, signed a statement defending global warming research in the face of criticism by sceptics, who seized on stolen emails to claim experts have been manipulating evidence to support a theory of man-made climate change.
A separate report on ocean acidification published at the climate talks in the Danish capital underlined the dangers of rising carbon dioxide emissions to the world's seas and coral reefs and the people who depend on them for food, livelihoods and protection from floods and storms.
As the impacts of rising emissions were highlighted, campaigners demanded rich nations put their "money where their mouth is" and agree to massive funding to help poor countries tackle climate change.
Billionaire philanthropist George Soros, speaking to delegates at the conference, warned the current offer for a "fast start" 10 billion dollar fund to help poor countries was "not sufficient".
Despite divisions among negotiators, momentum towards a deal continued with the Kremlin announcing Russian President Dmitry Medvedev would join more than 100 world leaders at the closing days of the talks.
And a raft of British ministers, including Gordon Brown, will attend the crunch meeting in the bid to get an ambitious deal on global warming, UK officials said.
EU leaders are meeting at a summit in Brussels today and tomorrow to discuss climate change, the economy, and a new jobs and growth strategy for Europe.
Environmentalists and aid agencies have urged EU leaders to disregard a letter from business lobby group Business Europe which calls for European countries to refrain from upping their target for emissions cuts from the weaker 20% level to 30%.
And they called for Britain's biggest business group, the CBI, to distance itself from the demand.
The level of emissions cuts that developed countries are prepared to sign up to and the efforts developing countries will make to curb the greenhouse gases causing climate change is one of the key issues of the conference.
The most vulnerable low-lying island states, led by Tuvalu, have called for more aggressive curbing of emissions than planned to keep temperature rises to below 1.5C, rather than the 2C target backed by developed countries, because of the risk rising sea levels pose to their nations.
The issue of finance also remains a major sticking point, with Mr Soros warning the gap between rich and poor countries on providing money could "wreck" the conference.
He suggested using International Monetary Fund (IMF) resources to provide immediate finance for poor countries to develop clean technology and adapting to climate change - a suggestion which met with mixed response among environmental and anti-poverty campaigners.
Under the plans, money that had been aimed at major developed economies to help with the global financial crisis could be redirected at developing countries to jump-start investment in areas including low carbon technology and reforestation and protection of forests.
Robert Bailey, Oxfam International's senior climate advisor said: "Soros' proposal shows exactly the kind of ambition and urgency we need to see from rich country governments themselves."
He added: "With just one week to go, it's time for governments to stop side-stepping climate finance and put their money where their mouth is."
But Tom Picken, international climate campaigner at Friends of the Earth, warned: "More money for developing countries is vital, but this proposal offers loans, not grants."
He said the scheme would only be worth exploring if it were on the basis of grants, not loans, was governed by the UN instead of the IMF and did not rely on carbon markets working in the future to give the necessary returns on projects to pay back the interest.
And Greenpeace International executive director, Kumi Naidoo, said: "Money is one of the keys to a good outcome in Copenhagen. It is needed to build trust to get a climate saving deal.
"But money alone will not do it. We need political will to clinch the fair, ambitious and legally binding treaty needed to avert catastrophic climate change."