The new research suggests China's emissions
China has already overtaken the US as the world's
"biggest polluter", a report to be published next month says.
The research suggests the country's greenhouse gas emissions have
been underestimated, and probably passed those of the US in
The University of California team will report their work in the
Journal of Environment Economics and Management.
They warn that unchecked future growth will dwarf any emissions
cuts made by rich nations under the Kyoto Protocol.
The team admit there is some uncertainty over the date when China
may have become the biggest emitter of CO2, as their analysis is
based on 2004 data.
Until now it has been generally believed that the US remains
"Polluter Number One".
Next month's University of California 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 say their figures are based on provincial-level
data from the Chinese Environmental Protection Agency.
Video showing the extent of China's smog
They say analysis of the 30 data points is more informative about
likely future emissions than national figures in wider use because
it allows errors to be tracked more closely.
They believe current computer models substantially underestimate
future emissions growth in China.
We are awaiting a formal comment from the UK Chinese Embassy, but
Dr Max Auffhammer, the lead researcher, said his projections had
been presented widely and no-one had raised a serious complaint.
All those concerned about climate change agree that China's
emissions are a problem - including China itself.
Global carbon emissions statistics were last
published in 2004. They show Chinese emissions began rising
rapidly in 2002.
University of California research suggests
China overtook the US as the worst producer of carbon
emissions in 2006
But China and many other developing countries struggling to
tackle poverty are adamant that any negotiated emissions reductions
should not be absolute, but relative to a "business-as-usual"
scenario of projected growth.
That is why this study is of more than academic interest.
If it becomes widely accepted that China's future emissions are
likely to be much higher than previously estimated, that will have
to factored into any future global climate agreement if the Chinese
are to be persuaded to take part.
In brief, although this study looks bad for China's reputation,
it may be good for China's negotiating position.
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.
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
"Our figures for emissions growth are truly shocking," he said.
"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.
"The only solution is for a massive transfer of technology and
wealth from the West."
He acknowledged that this eventuality was unlikely.
Those scientists aspiring to stabilise global emissions growth
before 2020 to prevent what they believe may be irreversible damage
to the climate may be wondering how this can possibly be achieved.
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