President Barack Obama today urged world leaders to confront climate change and warned of dire consequences if the world did nothing to curb rising carbon emissions.
Mr Obama aims to strike a deal to limit emissions of greenhouse gases in Copenhagen next week, where nearly 200 countries have been discussing ways to curb climate change.
The United States is the world's second-largest emitter of greenhouse gases after China, and the only developed country not in the existing Kyoto mechanism to lower carbon emissions.
"The world must come together to confront climate change," Mr Obama said in his Nobel Peace Prize acceptance speech in Oslo today. "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.”
At a news conference after the prize ceremony, he said the United States had done much work this year "to help to move international climate negotiations forward in an effective way".
But climate activists still fear that hitherto limited pledges by Washington may scupper a tough deal in Copenhagen. One banner near the City Hall, where Mr Obama received his award read: "Obama: you won it, now earn it - stop climate change!"
"The problem right now is that in fact the US is the number one impediment to the success of these talks and that the negotiators from the US are not putting emissions reductions on the table of an adequately aggressive kind," Greenpeace global warming campaign director Damon Molgen said. "This is an opportunity for Mr Obama to provide visionary leadership and to support creating a binding ambitious agreement...It's not a photo opportunity.”
"This is a moment...where this particular Nobel Prize winner will make his place in history or lose his place in history."
Mr Obama has said he will offer a US cut of 3 per cent below 1990 levels by 2020, or a reduction of 17 per cent from 2005 levels after sharp rises in recent years. That compares to offers by recession-hit developed countries that so far total about 14 to 18 per cent below 1990 levels by 2020.
The United Nations climate panel in 2007 outlined a scenario of cuts of 25 to 40 per cent below 1990 levels by 2020 to avoid the worst effects of climate change, such as wildfires, droughts, floods and rising sea levels.