A Pollution Paradox

Get this: Rampant pollution in China is actually cooling the climate, at least a little bit. Massive sooty dust clouds lift off Asia, drift across the Pacific, and make up about 80 percent of the pollution in West Coast air. Similar, though substantially smaller, clouds drift from America to Europe, and from Europe to central Asia. This worldwide migration of pollution, besides fouling the air for the breathing public, has a paradoxical effect on the climate. A portion of the emissions are carbon, and so contribute to the greenhouse effect that traps heat in the atmosphere. But the tiny dust particles and droplets actually reflect sunlight, preventing its heat from reaching the earth in the first place. Scientists are now trying to quantify that cooling effect, in an effort to better understand our complicated relationship with the climate, according to a story in the May 17 Christian Science Monitor.