George Bush and his government are now isolated in their own country on climate change, ex-Cabinet minister Stephen Byers has said.
Mr Bush has spoken of using new technology
Mr Byers is speaking for the International Climate Change Task Force at the UN summit on the issue.
He said the UK must engage with the US to persuade it to adopt climate change targets once George Bush leaves power.
And the US refusal to agree the Kyoto treaty should not stop other nations agreeing further targets, he said.
Mr Byers argued the US should be encouraged to tackle emissions in other ways before taking on targets at a later date.
'Isolated at home'
Mr Byers told BBC Radio 4's Today programme it was important the US did not stop the Kyoto signatories from discussing a successor agreement to cover the period after 2012.
The US Government did not believe in using binding targets but should be part of talks on controlling emissions through using cleaner energy and new technologies, he said.
But he hoped the US approach could merge with the targets-based measures once there was a change of president.
"There's been an attempt to engage - that is not the same as giving in to the American position - and increasingly it's becoming obvious in my view that the Bush administration is becoming isolated in its own country," said Mr Byers.
"There are a number of states, there are a number even of Republican senators who are beginning to recognise that emissions reductions are going to be the only way forward to tackle climate change.
"So there's that recognition, which is growing and I think we've got to find a way so that post the Bush administration we have an American administration which is prepared to come back and rejoin international community."
Negotiators at a climate change summit say they are making good progress in the talks in Montreal on implementing the Kyoto agreement to cut greenhouse gases.
They say a proposal by Saudi Arabia which would have delayed the system of policing targets has been removed.
But the UK Environment Secretary Margaret Beckett has warned against false euphoria.
She said several delegates were reminding the US that President Bush had agreed to make progress in Montreal.
But she added: "One of the things I often try to get across to people is it is a big mistake for people to focus only on the United States as the obstacle in negotiations like this.
"There are plenty of other people around with their own particular concerns, not all of whom are as positive as one would like."