NASA-funded study: Chinese practice of banning 50 percent of privately owned vehicles on any single day "could greatly reduce the threat of climate change"?

Reducing traffic at 2008 Olympics yielded large cut in CO2 | UCAR

BOULDER—China’s Olympian attempt to improve air quality during the 2008 summer games did more than provide a healthier atmosphere for the athletes. It also demonstrated that widespread changes in transportation patterns could greatly reduce the threat of climate change.

New research by an international team of scientists led by the National Center for Atmospheric Research (NCAR) indicates that China’s restrictions on motor vehicles had the side benefit of dramatically cutting emissions of carbon dioxide by 24,000 to 96,000 metric tons (about 26,500 to 106,000 U.S. tons) per day during the event.

To put this in perspective, the authors note that this reduction by a single city represents more than one-quarter of 1 percent of the emissions cut that would be necessary worldwide, on a sustained basis, to prevent the planet from heating up by more than about 2 degrees Celsius (3.6 degrees Fahrenheit) by the end of this century. That is the amount of heating generally considered to lead to major societal impacts.
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“The Beijing Olympics allowed us to actually measure what happens when people drive much less, and it turns out that it makes quite a substantial difference to our climate,” says NCAR scientist Helen Worden, the lead author. “People may think their choice of how to commute to work doesn’t make a difference, whether driving their cars or riding their bikes. But on a large scale, it really does.”

Funded primarily by NASA, the study was published in Geophysical Research Letters, a publication of the American Geophysical Union. It was co-authored by researchers at the University of Iowa, the University of Tsinghua in Beijing, Argonne National Laboratory, and the Jet Propulsion Laboratory. NCAR is sponsored by the National Science Foundation.

As China has industrialized in recent decades, residents of Beijing and other major cities have been subjected frequently to unhealthy levels of air pollutants. To provide better air quality during the 2008 Olympics, Chinese officials imposed stringent limits on motor vehicle use, including banning 50 percent of privately owned vehicles on any single day because of alternate-day driving requirements. They also imposed limits on industry and temporarily suspended construction activity.