Development and environment groups say they are delighted that President Obama will attend the UN climate talks in Copenhagen on 9 December, but are urging him to return to the conference after collecting his Nobel Peace Prize in Oslo.
"The world needs President Obama to tear up his schedule and get a return ticket back to Copenhagen," said Nelson Muffuh, the senior climate advocate of UK-based international development agency Christian Aid.
He added: "President Obama's personal leadership could make a critical difference to the talks – and nothing else in his diary could possibly be as important as steering the world off its current path towards climate chaos."
Christian Aid has campaigned throughout 2009 for world leaders including President Obama, President Hu Jintao of China, Prime Minister Gordon Brown and Prime Minister Manmohan Singh of India to attend the Copenhagen talks.
It believes that tackling climate change is such an urgent and vital task that national leaders must be personally involved - and the evidence is that they have got the message.