Professor John Schellnhuber, of the Potsdam Institute for Climate Impact Research in Germany, said the US was "climate illiterate" and that the rest of the world may be forced to agree a new deal without it.
"Nobody should dream of the possibility that numbers and targets for countries will be sealed in Copenhagen," said Schellnhuber, one of the world's foremost climate scientists. "If the US doesn't move then nothing will happen."
He added: "The US in a sense is climate illiterate. It is a deeper problem in the US, if you look at global polls about what the public knows about climate change. Even in Brazil and China, you have more people who know the problem, who think that deep cuts in emissions are needed."
He predicted that it could be several years before the US would be willing to take on carbon cuts that were ambitious enough to persuade countries such as China to set targets of their own. At UN talks last week, China and India made small steps forward on this issue, but Obama was unable to do the same.
"The political chances seem very slim that something will happen in Copenhagen and even in the years after," he said. "Maybe in the conferences following Copenhagen some countries – including China and the EU – whatever the US does, will say: we go ahead now. Why can't we save the world without the US? Why should that not happen?"
The US has by some distance the largest carbon emissions per capita in the world, and any deal without it would be significantly less effective at curbing global temperature rise.
Speaking on the fringes of a climate science conference at Oxford University today, Schellnhuber said the former US president, George Bush, was to blame for a decade of inaction on climate change, and that many in the Republican party and the wider US population still did not understand the need to act. European nations and others have been waiting for President Obama to engage with the issue in a way that Bush refused to.
28 September 2009
Its George W. Bush's Fault
In today's Guardian Hans Joachim Shellnhuber, a German climate scientist and advisor to Angela Merkel, gives a sobering view of the upcoming Copenhagen climate conference: