Philippe Naughton in Copenhagen
The top African negotiator at the Copenhagen climate summit called on Barack Obama today to live up to the world's expectations of him as a Nobel laureate and commit America to a meaningful global agreement to tackle global warming.
The call from Lumumba Di Aping of Sudan, who chairs the G77 group of developing nations, came as President Obama visited the Norwegian capital Oslo - just 300 miles to the north - to pick up a Nobel Peace Prize that many feel is premature.
Mr Di Aping, who has spent the opening days of the Copenhagen summit railing against Western attempts to impose a climate deal, said the the world "cannot achieve an equitable and a just deal that would save the planet without the participation of the United States".
He repeated a call for American to ratify and join the Kyoto Protocol, which Mr Obama has already made clear he will not do. The US walked away from the landmark deal to cap CO2 emissions in 2001 when President Bush decided that it would be too costly for American business.
"We should not waste time trying to reinvent what we have already achieved," Mr Di Aping said. "That simply undermines the fight against the emissions. That's the challenge President Obama needs to rise to - that's what we expect of him as a Nobel prizewinner, that is what we expect of him as one of the new advocates of multiateralism."
The Sudanese diplomat backed an innovative idea proposed earlier today by the financier George Soros for industrialised nations to free up unused Special Drawing Rights (SDRs) - foreign exchange reserves issued by the International Monetary Fund - to held poorer countries head off cope with global warming.
Mr Soros, himself worth an estimated $11 billion, wants to create a $100 billion fund to invest in and finance reforestation and agriculture projects and says it could help break a financing logjam in the Copenhagen negotiations - although he doubted that the United States would want to get involved.
Picking up on the idea, Mr Di Aping immediately doubled it to $200 billion and said that the question should be asked of the US Congress: "You approve billions of dollars in defence budgets: why can't you approve $200 billion to save the world?"
The SDR idea looks unlikely to gain much traction in Copenhagen, but beyond the dramatics there were the first signs of some serious progress towards a deal.
Mr Obama is due to arrive in Copenhagen next Friday along with at least 110 other world leaders, the latest among them President Medvedev of Russia. The US leader will doubtless remember his last trip to Copenhagen when he came to tout Chicago as potential host of the 2018 Olympic Games, only for IOC members to choose Rio de Janeiro instead.
The US President had originally planned to stop off in Copenhagen yesterday, en route to the Nobel ceremony, but decided last week to come for the final day of the talks on December 18, when any deal would be signed by the assembled leaders.
That suggested a degree of optimism in the American camp that something worth signing will emerge from the two weeks of negotiations in Copenhagen.
Because of the US refusal to ratify the Kyoto Protocol, which obliged developed nations to cut CO2 emissions by 5 per cent on 1990 levels by 2012, the Copenhagen conference has twin-track negotiations on reaching a successor accord to Kyoto and a separate pact to which the United States would also sign up.
But there is a growing feeling among delegates from developed and emerging economies that there is no point sticking with the Kyoto Protocol if the United States is not involved and the summit should focus its attention on an entirely new treaty.
Developing nations would resist such a proposal - and reacted angrily to a "Danish text" which effectively took such a line - but may have no choice if they want to receive the vast sums on offer to help them mitigate the effects of global warming.
The EU's chief climate negotiator, Anders Turesson, complained today that the slow pace in the formal plenary session of the conference was preventing progress elsewhere, including in the negotiating track with with the Americans are most closely involved.
The plenary session has been tied up over calls from developing nations for a much more ambitious target on limiting global warming.
More than half the countries at the 192-nation back a call from the Pacific island of Tuvalu - which says it is already sending climate refugees abroad - for a formal target of limiting rises in termperatures to 1.5C above pre-industrial levels. Industrialised nations have backed a 2C target.
In his Nobel acceptance speech, Mr Obama said that world had to come together to confront climate change.
"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.