The Rain in China Falls Mainly on the Plains, Thanks to Pollution

Mountains are fountains. Humid air crashes into upthrusted rock and releases its water in the form of rain, snow or ice. But the tiny particles created when fuel is burned—aerosols—can interfere with this process by providing even more impurities in the air on which water can condense. The many more resulting smaller droplets collide less often, thus forming fewer raindrops and, ultimately, less rainfall. Or so the theory goes. And now, records stretching back 50 years for a mountaintop in China strongly support this idea.

Atmospheric scientist Daniel Rosenfeld of The Hebrew University of Jerusalem, Jin Dai and colleagues from the Meteorological Institute of Shaanxi Province in China and Zhanyu Yao of the Chinese Academy of Meteorological Sciences studied the records of precipitation and visibility at Mount Hua in central China. The site, one of five sacred mountains in China (familiar to many as a backdrop in martial arts films), has had a meteorological observatory on its peak since 1954.