Tony Blair's vision of a new deal on climate change at the forthcoming summit of G8 industrialised nations looks likely to be heading for failure.
By Roger Harrabin
BBC Environment Correspondent
President Bush's chief climate negotiator has told the BBC that the USA will agree to only one of three of Mr Blair's targets for the Gleneagles meeting.
Mr Blair wants agreement on targets for cutting emissions
Mr Blair hopes the Americans will agree that recent developments in climate science have proved the need for urgent action to protect the planet from the
risk of catastrophic harm.
He wants to tie the Americans into a new international agreement on cutting emissions now they have refused to ratify the Kyoto protocol.
And he wants the US to commit more of its wealth towards developing new technologies that will allow people to keep their current lifestyles without damaging the climate.
But Mr Bush's climate negotiator Harlan Watson said the president would agree to only one of the three.
Mr Watson said the US would continue its investment in technology. But he said the science on climate was still uncertain and did not merit urgent action.
Mr Watson said the US would not commit to any new international climate agreement on cutting emissions.
He said the president had committed to reducing the amount of greenhouse gas emitted for every dollar earned in the economy. But he would not agree to the overall cuts in emissions to which most other leading nations aspire.
The UK government's chief scientist says industrialised nations need to cut emissions by at least 60% and believes simply making production a little more efficient is irresponsibly inadequate.
Scientists are particularly angry that the US' reluctance to move urgently on the issue is holding back the rest of the world.
The Canadians and Japanese are resisting further emissions cuts because their firms fear being out-competed by US companies feasting on cheap energy.
The US will not agree cuts until China and India have agreed cuts too - but these nations complain that their per capita energy use is a fraction of that in the USA. The Americans, they say, must lead the way on cutting emissions.
A number of experts who have seen Mr Blair attempting to tackle climate change recently say he appears to believe that he can harness a special relationship with President Bush to persuade him to change his mind.
Mr Watson did not hold out any hope of that outcome during his interview with the BBC.