Leaders of the Commonwealth countries called Saturday for a legally binding international agreement on climate change and a global fund with billions of dollars to help poor countries meet its mandates.
The 53-nation meeting was the largest gathering of international leaders before next month's global climate summit in Copenhagen.
The leaders said a deal should be adopted no later than next year and the support money should be available simultaneously, providing up to $10 billion a year starting in 2012.
At least 10 percent of the fund should be dedicated to small island and low-lying coastal nations that are at risk of catastrophic changes from global warming, the group said.
"Climate change is the predominant global challenge," the Commonwealth leaders said in a joint declaration. "For some of us, it is an existential threat."
The document called for a "legally binding" agreement by the world's nations.
Danish Prime Minister Lars Loekke Rasmussen and U.N. Secretary-General Ban Ki-moon, making rare appearances at a Commonwealth meeting to help drive the climate discussion, portrayed the joint declaration as further evidence of growing momentum for next month's summit.
"I will leave Trinidad fully convinced that it will be possible to reach an ambitious agreement in Copenhagen," Loekke Rasmussen told reporters after the Commonwealth leaders issued their statement following a private meeting.
Some 90 countries have now agreed to attend the summit in Denmark.
The Commonwealth countries, which represent about a third of the world's population, said in the statement that the members all agreed on the need for an ambitious program to reduce the risks of climate change.
But they added that they have a "range of views" on whether the average global temperature increase should be constrained to below 1.5 degrees Celsius or to no more than 2 degrees above pre-industrial levels.
Their endorsement of a global fund came a day after British Prime Minister Gordon Brown and French President Nicolas Sarkozy, both attending the meeting in the twin-island Caribbean nation of Trinidad and Tobago, also backed the idea.
Brown said Britain would contribute $1.3 billion over three years, but other countries have not yet specified their commitments.
The biennial meeting of the Commonwealth, made up mostly of former British colonies, attracted an unusual level of attention this year because of climate change. It brought together some of the key countries in the global debate, including India, Canada and Australia, amid debate over cutting carbon emissions and the economic effects of those cuts.
Indian Prime Minister Manmohan Singh said Friday that his country is willing to sign an ambitious global target. But he set no specific figures and insisted it be accompanied by "equitable burden sharing."
Other leaders were still working on emissions goals.
Canadian Prime Minister Stephen Harper suggested his government's plan would be similar to the American pledge. The White House said this week the U.S. would reduce emissions by 17 percent from 2005 levels by 2020 and achieve a 41 percent reduction over the following 10 years.
"Those targets are completely in line with the government of Canada's policy," Harper said. "So I look forward to having a comprehensive agreement in Copenhagen where we will actually get on with actually reducing emissions as opposed to just setting abstract targets."
Australian Prime Minister Kevin Rudd told reporters progress was being made. "You see as each day passes a large number of states come forward with their own national commitments," he said.