Industrialised nations' greenhouse gas emissions dipped 0.7 per cent in 2011, helped by a US shift from coal power plants.
Data compiled by Reuters based on submissions by 42 industrialised nations this month used to judge compliance with UN treaties showed combined emissions slipped to 17.1 billion tonnes in 2011 from 17.2 billion in 2010 – down 6.4 per cent from levels in 1990, the UN benchmark year for judging progress in combating global warming.
The figures based underscore how continued worldwide growth in emissions is increasingly led by China and other emerging economies.
"For the United States, it's mainly a shift from coal to gas in power plants," says Steffen Kallbekken, research director at the Center for International Climate and Environmental Research, Oslo. "For Europe it's primarily weak economic activity."
Senior government officials from around the world will meet in Bonn, Germany, next week for a new round of negotiations on an emissions deal that is meant to be agreed in 2015 and enter into force in 2020. The last attempt at an accord failed in Copenhagen in 2009.
In the US, the world's No.2 emitter behind China and ahead of the European Union, greenhouse gas emissions dipped to 6.67 billion tonnes in 2011 from 6.79 billion in 2010.
That put US emissions 7 per cent below their 2005 levels. President Barack Obama wants a cut of 17 per cent from 2005 levels by 2020 but has lacked support for that drive in the Senate.
European Union emissions fell by 3.3 per cent in 2011, according to official accounting of gases ranging from carbon dioxide to methane, meaning EU emissions were 18.5 per cent below 1990 levels in 2011.
This mean the bloc is apparently on target for a promised cut of at least 20 per cent by 2020 despite a plunge in the price of carbon dioxide on an EU market that has removed a main spur to action.
Elsewhere, emissions rose in 2011 in nations including Russia, Japan and Turkey while they were little changed in Canada and Australia.
But the unexpectedly rapid rise of emissions in China and other emerging economies such as India and Brazil in recent years is pushing up global emissions and complicating talks among 200 nations on a new UN accord aiming to slow climate change.
Emerging economies are not obliged to submit annual emissions data to the UN Climate Change Secretariat, but other studies show that worldwide emissions are rising.
A Global Carbon Project, for instance, estimates that world emissions from fossil fuels and cement grew by 3 per cent in 2011 and by 2.6 per cent in 2012 and it says China's surging emissions were responsible for most of the global growth.
"Per capita emissions of China are now pretty much on the same level as those in the EU," said Jos Olivier, senior scientist at the PBL Netherlands Environmental Assessment Agency.