NEW YORK, September 21, 2009 (AFP) - As world leaders gather for key climate talks here, small island nations Monday warned they were running out of time with rising seas threatening to wipe them off the map.

Spread across the Earth's oceans, the planet's tiniest members grouped together in the Alliance of Small Islands States (AOSIS) are hoping to make their voices heard 100 days before UN-hosted climate talks in Copenhagen.

UN chief Ban Ki-moon and former British prime minister Tony Blair also urged governments around the world to publicly commit themselves to tackling global warming as they opened New York Climate Week.

"We need a commitment for a fair deal in Copenhagen," Ban said.

Climate negotiators have spent the last two years working toward a make-or-break summit in Copenhagen this December, expected to ink new targets for global emissions beyond 2012, when the Kyoto Protocol expires.

"The will is actually there. The question is, can we find the way to match the will," added Blair at the ceremony held in the New York library.

"It is about getting a global agreement. To pass to the future generations a world that hopefully is better than the one we have today, but at least is not worse."

AOSIS, which was meeting separately here, has dubbed itself the "moral voice" of the Copenhagen negotiations while the European Union prides itself on taking the lead, with member states agreeing to make 20 percent cuts in CO2 emissions by 2020 from 1990 levels.

EU leaders have said they are ready to commit to 30 percent cuts if the rest of the world does likewise to attain the overall goal of restricting global warming to two degrees Celsius.

But such a cut in rising temperatures is still too warm for many low-lying and island nations.

"Small island countries need to say that it is tantamount to declaring their extinction, because the consequences of going to a two degree Celsius increase are such that whole nations are to disappear," UN climate negotiator Yvo de Boer told AFP.

Instead AOSIS, which met separately here Monday, is demanding that the new Copenhagen climate agreement limit temperature increases to as far below 1.5 degrees Celsius as possible, drumming home their mantra "1.5 to stay alive."

AOSIS president, Dessima Williams, said last week: "More recent science shows that we are on track for a sea level rise of at least one and maybe two meters by the end of the century.

"That would spell disaster, even disappearance, for some of our islands."

She said even just a 0.8 Celsius rise on the world thermometer was having dire consequences for island nations already witnessing severe coastal erosion, floods, dying coral reefs, and extreme weather.

The alliance is urging industrialized nations to cut gas emissions by 2020 by 45 percent compared with 1990 levels.

Blair said: "We need short term, medium and long term actions. To stop deforestation is the short term, and then we need to start investing now in the technologies of the future."

De Boer said he was eagerly awaiting what Chinese President Hu Jintao would have to say about climate change on Tuesday.

"I have very high expectations on what President Hu will be announcing in the UN tomorrow; it's going to be ambitious," he said.

He predicted that China could unveil policy measures that would make Beijing a "world leader in addressing climate change."

China's director of climate change, Su Wei, told the New York Climate week ceremony that: "Climate change threat is real and imminent."

The United States, which consumes 25 percent of the world's energy and is the world's biggest polluter, is also in the dock with many fearing Washington is too preoccupied with other problems to devote much time to battling global warming.