The world's carbon dioxide emissions is likely to fall by more than 2% this year - the biggest drop in 40 years - mainly due to the global recession.
Measures such as emissions trading and China's economy-wide drive to increase energy efficiency have also played a part, but the International Energy Agency estimates that the recession is responsible for about three-quarters of the fall.
The close relationship between gross domestic product and carbon emissions is well documented, so many commentators were expecting that the recession might cause emissions to drop. But the BBC reports that the size of the fall has come as something of a surprise.
As well as curtailing the business sector's energy use by applying a general economic brake, the straitened circumstances have reportedly led to deferments on investment in new fossil fuel plants.
One of the main stumbling blocks in the process of trying to forge a new United Nations climate treaty at Copenhagen in December has been the reluctance of some industrialised countries, in particular the United States, to pledge emission cuts big enough to placate developing countries.
The IEA suggests its findings show that emissions can be cut more easily than some governments have assumed.
The news came as leaders gathered at the UN for a day of climate talks convened by Secretary-General Ban Ki-moon.
Attending the launch of Climate Week at the New York State Library alongside former British prime minister Tony Blair, Mr Ban said world leaders had a moral imperative to sign a new agreement on reducing greenhouse gas emissions in December.
New Zealand Prime Minister John Key is attending the climate talks and will meet Mr Ban on Wednesday.
'National charters' idea wins Flannery's favour
Australian ecologist Tim Flannery, who as chair of the Copenhagen Climate Council is also in New York, says he's worried that a global agreement on climate change will die a death by a thousand cuts, and the world will face a "dire situation" if talks fail.
Consequently, Mr Flannery says, he approves of Australian Climate Change Minister's Penny Wong's proposal to allow developing countries to sign up to their own "national charters" of commitment rather than "emissions targets".
"I think the time is right now to start considering that approach," he said on ABC1's Lateline television programme.
"We've gone just about as far as we can under the old approach, and we haven't made the progress that we need.
"No-one can guarantee success in this, but it does hold the promise at least of unlocking further cooperation from those so-called developing countries."
China, Brazil 'not developing countries any more'
Mr Flannery says developed nations should not need to compensate countries like China that are asking for a global fund to help them meet emission reduction targets. Countries like China, he says, need to carry responsibility.
"There really is genuinely a need to get adaptation funding and mitigating funding to the poorest countries, but you know the world has moved on since 1992 when we included China and Brazil and Mexico as developing countries.
"I don't think they can justifiably be called developing countries in the same sense any more. At the moment they can hide behind that label, but we have to find a way forward."
Potential trade wars if diplomacy fails
Mr Flannery warned of potential trade wars if diplomacy in Copenhagen fails, pointing out that the Waxman-Markey bill, recently passed in the US, contains a clause that by 2018 a board of tariffs can be erected against countries that are not carrying their weight with the climate issue.
"Now [the Waxman-Markey bill is] just one of a lot of potential triggers, but you can imagine if this problem grows, and we get mass migration of people or really serious water shortages in South Asia, that the triggers are there for conflict," he said.