China's carbon dioxide emissions are growing much faster than anticipated and are on pace to double during this decade. Forecasts of global warming don't take this growth into account, so scientists may be underestimating how fast the planet will heat up.
When scientists last tried to project China's contribution to global warming, it was the late 1990s. Asia was in a recession and China's emissions weren't growing particularly fast.
But Maximilian Auffhammer of the University of California, Berkeley, says things have changed radically since then. Since 2000, carbon dioxide emissions have been "off the charts," he says.
For example, in 2004, emissions from China grew by 14 percent — or the equivalent of an additional Germany or England.
Auffhammer and a colleague have used detailed information from within China to estimate what emissions will be like through the end of the decade. His forecast is being published in the Journal of Environmental Economics and Management.
The average of all the scenarios predicts continued growth in emissions of about 10 percent to 11 percent a year. That is roughly what Auffhammer has observed over the last four years — and it would lead to a doubling of emission levels every decade.
By this reckoning, China overtook the United States as the leading emitter of carbon dioxide about a year ago. And its emissions are now increasing about 10 times faster than in the United States.
That also means that carbon dioxide is building up in the atmosphere a lot faster than the United Nations science panel, the IPCC, figured in a major report last year.
Gregg Marland works at the Oak Ridge National Laboratory, which compiles emissions figures from around the world. He says economists are now starting to update their forecasts, knowing that more rapid increases in emissions mean more rapid global warming.
But Marland says it's a mistake to look at China in isolation.
"A significant fraction of emissions from China are to produce goods that will be consumed in the United States. So it's wrong ... to point fingers at individuals or individual countries. We have to recognize that we're all in this together," he says.
And China isn't just ignoring the issue. The country's economy is growing rapidly as it struggles to bring a large percentage of its population out of poverty.
But Deborah Seligsohn, who works for the World Resources Institute in Beijing, says in the past few years, China has instituted policies to slow emissions growth. So China might end the decade better than scientists are currently forecasting.
"What happens is a complex mix of business behavior, policy behavior, financial behavior," she says.
But Berkeley's Auffhammer says even if China does slow its emissions, the recent building boom in coal-fired power plants — which can operate for 40 to 80 years — will have repercussions for decades to come.
"Any policy now is not going to tear down existing, costly, capital equipment in China. But we should really worry about what the next power plant they put in next week and the week after and the week after is going to be," he says.