Climate impact of traffic emissions eyed

China's efforts to improve air quality during its 2008 Olympics show changes in transportation patterns can reduce threats of climate change, scientists say. China's restrictions on motor vehicles in Beijing dramatically cut emissions of carbon dioxide by about 26,500 to 106,000 tons during the event, new international research led by the National Center for Atmospheric Research in Boulder, Colo., found. Such a 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 3.6 degrees Fahrenheit by the end of this century, an NCAR release said Tuesday. While reduced traffic leads to lower carbon dioxide emissions, precise estimates for an actual urban area have been difficult to calculate, researchers said. "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," NCAR scientist Helen Worden said. "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." The research, funded primarily by NASA, was published in Geophysical Research Letters.