OSLO Soaring greenhouse gas emissions in China and other emerging nations are eroding rich nations' historical responsibility for causing global warming, and this could complicate U.N. talks starting in Mexico this month.
Washington says an unfair "Berlin Wall" separates a group of 40 industrialized countries, which are expected to cut emissions sharply by 2020, from other countries led by China which are due only to slow the rise in their emissions by 2020.
Analysts see little prospect of an end to that divide, enshrined in the 1992 Climate Convention, partly because Washington itself is not leading the way with cuts meant to avert more floods, heatwaves, droughts and rising sea levels.
Annual U.N. climate talks in Cancun, Mexico, from November 29 to December 10, are likely to hear more insistent calls than in the past for a new scale of responsibilities to reflect the rising influence of nations such as China, India and Brazil since 1992.
"Developing country emissions, especially of China and India, are at the high end of the range" projected in a 2007 U.N. report that is the main government guide for global action, said Niklas Hoehne, of climate consultancy Ecofys.
"But if you look at it in terms of per capita emissions, the story is still very different. China is around the world average and still a factor of four smaller than the U.S.," he said.
The rise in greenhouse gas emissions in many emerging nations, caused by rapid economic growth that is reducing poverty -- a top global priority -- contrasts with a fall in many rich countries, caused by economic crisis.
Under the 1992 Convention, 40 industrialized nations in Annex One, with a fifth of the world's population, are meant to cut emissions first because they have stoked global warming by burning most fossil fuels since the Industrial Revolution.
As the years go by, their proportion of total emissions is falling.
U.S. climate envoy Todd Stern said in a speech last month that a "new paradigm" was needed since developed nations now account for just 45 percent of world emissions, a share that is set to fall to 35 percent by 2030.
He said China had overtaken Russia as the number two emitter of greenhouse gases throughout history behind the United States, and had eclipsed the per capita emissions of France.
Several analysts said Stern's calls were premature.
"It's a bit too early" to talk of a big shift of responsibility, said Susanne Droege, head of research in global issues at the German Institute for International and Security Affairs.
She said Washington wanted to distract attention from its failure to legislate cuts in emissions by focusing on the next generation of emitters. President Barack Obama's hopes of making cuts have been derailed by Republican mid-term election gains.
Terry Barker, Director of the Cambridge Center for Climate Change Mitigation Research in England, said faster-than-expected growth in emerging nations meant those nations would have to bring forward their carbon curbing plans by a year or two.
"It brings forward the time when developing countries, if they are serious about achieving the targets, will have to start reducing their emissions," he said.
Countries like Singapore and South Korea long ago shot past the per capita emissions levels of some of the 40 nations, from Australia to Russia, in Annex One. Developing nations fear they would have less influence if split up.
Some experts said it seemed a stretch to say that China had overtaken France in per capita emissions -- Stern did not define what emissions he meant, but carbon emissions from energy use are the easiest to estimate.
Among published estimates for 2009, BP plc statistics on carbon dioxide emissions from energy put France on 6.3 tonnes per capita and China on 5.6 tonnes. The gap is large, but China is growing rapidly.
The OECD forecasts Chinese gross domestic product growth of 11.1 percent in 2010 and 9.7 percent in 2011.
The 2007 report by the U.N. panel of climate scientists set out a scenario under which Annex One nations cut emissions by between 25 and 40 percent by 2020 from 1990 levels to avoid the worst of global warming.
In the same scenario, poor nations would merely have to have a "substantial deviation" so that their emissions increase more slowly than gross domestic product by 2020.
(Editing by Tim Pearce)