China emits over a quarter of the world's carbon--some 10 billion tons. That's twice what we pump out here in the U.S. But before the finger-wagging begins, consider that a quarter of China's CO2 emissions come from making exports--in other words, stuff for countries like us. "So we're talking about five to six percent of global emissions are in these goods being exported from China. And that may not sound like a lot, but five or six percent of 35 billion tons is a lot of CO2."

Steve Davis is a climate energy scientist at the University of California Irvine. He and his colleagues wanted to see whether outsourcing manufacturing to China--which happens to be good for our wallets--is also good for the planet. Spoiler alert: doesn't look like it.

A Chinese container ship passes under the Bay Bridge near San Francisco, Calif. in 2007. (Credit: Darin Marshall/Flickr)

"Because China is so reliant on coal for their energy, and because also they use less advanced technologies and processes in some cases, there's a lot more CO2 being produced than if those same goods were made in developed countries." And that's especially true in certain areas of China, like the provinces of Yunnan or Guizhou. "For every dollar of stuff being exported from those provinces, you're getting vastly more CO2." The study is in the journal Nature Climate Change. [Zhu Liu et al, Targeted opportunities to address the climate–trade dilemma in China]

China does plan to launch a cap-and-trade system in 2017, which might iron out some of these regional inefficiencies. But the real issue--is our consumer culture. "At the end of the day, consumption in and of itself is driving a lot of the problems we're having environmentally. Both climate change and others." So we could either buy less--which seems unlikely--or, to avoid stuff with a dirty carbon past, this might just be one more motive to go local.

-- Christopher Intagliata



[The above text is a transcript of this podcast. Scientific American is part of Nature Publishing Group.]