President George W Bush has ruled out US backing for any Kyoto-style deal on climate change at the G8 summit.
Bush says new technologies are the way forward
Speaking to British broadcaster ITV, he said he would instead be talking to fellow leaders about new technologies as a way of tackling global warming.
But he conceded that the issue was one "we've got to deal with" and said human activity was "to some extent" to blame.
Tony Blair is hoping for agreements on climate change and Africa when he hosts the summit in Scotland this week.
Mr Bush said he would resist measures that were similar to the 1997 UN Kyoto Protocol, involving legally binding reductions on carbon emissions, which Washington never ratified.
"If this looks like Kyoto, the answer is no," he said in an interview with ITV's Tonight With Trevor McDonald programme to be broadcast on Monday.
"The Kyoto treaty would have wrecked our economy, if I can be blunt."
He said he hoped the other G8 leaders would "move beyond the Kyoto debate" and consider new technologies.
He said the US was investing in developing clean energy techniques such as sequestration of carbon dioxide in underground wells, hydrogen-powered cars and zero emission power stations.
UK Environment Secretary Margaret Beckett told the BBC's Today programme that negotiations were likely to "go to the wire".
"I think what matters more than the exact theology is where people end up," she said.
"What we hope for is quite an ambitious action plan on steps that the international community can take and also agreement to try to take forward discussion and dialogue about the future."
French President Jacques Chirac has said he is hopeful of reaching a deal on climate change, but German environment minister Juergen Trittin said he was "very sceptical on the willingness of the US to move".
One of Mr Bush's main domestic critics on global warming, Senator John McCain, called the president's approach on the issue "disgraceful".
"I'm not quite sure how you'll bridge the gap," he told the BBC's Today programme, but he said he hoped the president and Mr Blair would be able to forge a compromise.
In the ITV interview, Mr Bush showed signs of coming into line with general world opinion by describing climate change as "a significant, long-term issue that we've got to deal with".
He has previously opposed action on climate change in favour of further studies on the issue.
WHAT IS THE G8?
Group of seven major industrialised states and Russia
Canada, France, Germany, Italy, Japan, Russia, UK, US
Originally set up to discuss trade and economic issues
Now leaders discuss global issues of the day
2005 Summit agenda
But he rejected the idea he should support the British prime minister's G8 plan in return for his support over Iraq.
"Tony Blair made decisions on what he thought was best for keeping the peace and winning the war on terror, as I did," he said.
"So I go to the G8 not really trying to make him look bad or good, but I go to the G8 with an agenda that I think is best for our country."
On the issue of tackling African poverty, President Bush signalled he was ready to abandon US farm subsidies - but only if the European Union was prepared to scrap its Common Agricultural Policy.
Farm subsidies are said to unfairly distort the world market faced by African farmers.
"We've got agricultural subsidies, [but] not nearly to the extent that our friends in the EU have," he said.
The G8 leaders - from Britain, Canada, Germany, France, Italy, Japan, Russia and the US - meet in Gleneagles on Wednesday for the start of the three-day summit.