As the U.S. continues to resist committing to an agreement to combat climate change, its former president Bill Clinton is taking his pro-Kyoto message to the world stage -- raising the ire of American officials.

Clinton spoke Friday, the final day of the Nov. 28-Dec. 9 UN summit on climate change in Montreal. He was invited to the event by the Sierra Club of Canada.

And while many are welcoming him, U.S. delegates attending the conference team are not.

"They haven't protested formally, but they're annoyed," a source in the Canadian government told The Associated Press. "They're not infuriated, but they're not thrilled."

Although the U.S. isn't one of the 157 countries that have signed onto the Kyoto accord, environmentalists were hopeful that it would sign a separate agreement for all nations.

Canada is hoping nations, not just ones under Kyoto, would sign a deal to hold open-ended talks about a long-term strategy to fight climate change.

But environmentalists indicated they were losing hope that the U.S. would sign on -- which would seriously dampen efforts to develop a strategy to fight global warming past 2012, when the first Kyoto Protocol commitment ends.

But Clinton encouraged the delegates to press on.

"There's no longer any serious doubt that climate change is real, accelerating and caused by human activities. We are uncertain about how deep and time of arrival of the consequences, but we are quite clear that they will not be good," said Clinton.

He put down the main U.S. fear about Kyoto -- that it would hurt the economy by chaining it to greenhouse gas reductions that were not achievable.

That claim, he said, "was flat wrong."

"And we know with every passing year we get more and more objective data (that) if we had a serious disciplined effort to apply on a large-scale, existing clean energy and energy conservation technologies -- we could meet and surpass the Kyoto targets easily in a way that would strengthen, not weaken, our economy," said Clinton to applause from the delegates.

Clinton's address was been designated as a "side event" to the conference. However, it was held in the main conference hall, and played to a large, admiring audience.

As president, Clinton championed the Kyoto Protocol, which sets out limits by which industrialized countries must reduce greenhouse gas emissions and five other gases below 1990 levels by 2012.  He was never able to get it through the U.S. Senate.

U.S. President George Bush never backed the plan, saying it would harm the economy. It still has not been ratified by the U.S.

More recently, the U.S. has rejected suggestions it rejoin future negotiations to set emission controls for the period after 2012, when the Kyoto framework expires.

The U.S. accounts for about a quarter of the world's greenhouse gas emissions, and some have argued that the Kyoto Protocol can't work without its participation.

This is the first annual UN climate conference to be held since the Kyoto Protocol took effect in February. The two-week conference was attended by delegates from more than 180 countries.

Only two developed nations, the United States and Australia, have rejected the agreement, worked out in 1997 in Kyoto, Japan.

The protocol sets out language calling on its member nations to begin talks now on emission controls after 2012, and it appears as if those groups were close to an agreement on a process for completing such talks by 2008.

"We're looking forward today to seeing some final agreements about how the Kyoto Protocol will be extended and deepened in the years after 2012, leading to further emission reductions from countries across the world," said Tony Juniper, vice-chair of Friends of the Earth International.

As for the U.S. stance, Juniper said that while Bush is opposed to the Kyoto treaty, many others in the U.S. see the benefits of investing in new technologies to fight global warming.

"That's President Bush's choice, but his citizens, his leaders at the state and city levels and scientists are saying 'Let's do something different, something much more modern and much cleaner'," Juniper told CTV Newsnet on Friday.