A new report has determined that China has already overtaken the US as the world's "biggest polluter", saying that the country's greenhouse gas emissions have been underestimated, and probably passed those of the US in 2006-2007.
According to BBC News, the report, made by University of California researchers, will be carried out in the Journal of Environment Economics and Management next month.
Until now, it has been generally believed that the US remains "Polluter Number One".
But now, the new report warns that unless China radically changes its energy policies, its increases in greenhouse gases will be several times larger than the cuts in emissions being made by rich nations under the Kyoto Protocol.
The researchers believe that until now, current computer models substantially underestimated future emissions growth in China.
But the new study, led by Dr Max Auffhammer, used an analysis of 30 data points, which is more informative about likely future emissions than national figures in wider use because it allows errors to be tracked more closely.
Dr Auffhammer told BBC News that his projections had made an assumption that the Chinese government's recent aggressive energy efficiency programme would fail, as the previous one had failed badly.
"Our figures for emissions growth are truly shocking," he said.
But, the Chinese - and the UN - insist that rich countries with high per capita levels of pollution must cut emissions first, and help poorer countries to invest in clean technology.
America's per capita emissions are five to six times higher than China's, even though China has become the top manufacturing economy.
US emissions are still growing too, though much more slowly.
"But there is no sense pointing a finger at the Chinese. They are trying to pull people out of poverty and they clearly need help," said Dr Auffhammer.
"The only solution is for a massive transfer of technology and wealth from the West," he added.