Former US vice president Al Gore today forecast America's attitude to climate change would be different once President Bush steps down from power.
He told the Bali global warming conference that his country was "principally responsible" for blocking progress on a new international agreement.
However he advised delegates not to get angry, but to wait for the 2008 US presidential election.
"Over the next two years, the United States is going to be somewhere it is not now," said Mr Gore, who flew to the Bali meeting after receiving the Nobel Peace Prize in Norway on Monday.
"One year and 40 days from today, there will be a new inauguration in the United States," he said.
"I must tell you candidly that I cannot promise that the person who is elected will have the position I expect they will have, but I can tell you I believe it is quite likely."
The former presidential candidate turned climate crusader won applause when he announced: "My own country, the United States, is principally responsible for obstructing progress here in Bali.
"Targets must be a part of the treaty."
He said the US Congress was moving legislation forward to impose binding emissions caps in the United States for the first time, laws that may be vetoed by Mr Bush.
Many US cities were are taking their own actions paralleling the Kyoto Protocol, he said.
He told the delegates they had two choices: "You can feel anger and frustration and direct it at the United States of America, or you can make a second choice. You can decide to move forward and do all of the difficult work that needs to be done."
Gore, who helped in the final negotiation of the Kyoto pact in 1997, also called for implementing a successor agreement to Kyoto two years early, in 2010. The first implementation period of the Kyoto pact expires at the end of 2012.
"We can't afford to wait another five years," he said.