UN climate forum opens in Bali

But Washington refused to endorse mandatory emissions cuts, seen by many governmental delegations at the meeting as crucial for reining in rising temperatures.

Faced with melting polar ice and worsening droughts, delegates from nearly 190 countries, including Canada, opened the two-week conference with pleas for a new climate pact to replace the Kyoto Protocol, which expires in 2012. That deal required the 36 signatories to cut emissions by 5 per cent from 1990 levels.

A key goal of the conference will be to draw in a skeptical United States, now the sole industrial power that has refused to ratify the Kyoto Protocol, citing fears it would hurt the U.S. economy because cuts aren't required of rising economies like those in China and India.

"We're not here to be a roadblock," said Harlan Watson, a top U.S. climate negotiator. "We're committed to a successful conclusion, and we're going to work very constructively to make that happen."

Federal Environment Minister John Baird, representing Canada at the two-week event, has said any new deal must include binding emission reduction targets for all the world's major greenhouse gas producers, including the U.S.

Both Baird and Prime Minister Stephen Harper have stated all major emitters must sign on to any new accord to make it effective.

"The only way we're going to get an effective international agreement is to get everyone to sign on at one time," Harper said at a meeting of Commonwealth leaders in Uganda last month. "We already saw at Kyoto, if we get a third of the world to sign on and wait for the other two thirds, it's never going to happen."

The Americans, however, were forced to repeatedly defend their refusal to embrace emission caps after Australia's new prime minister signed papers to ratify the 1997 Kyoto deal, reversing the decision of his country's previous, conservative government.