Smog Cloud Menaces Asia

An enormous cloud of smog over southern Asia threatens 2 billion people with flooding and drought, a new study shows. The "Asian Brown Cloud" is melting Himalayan glaciers, the Times of London reports, and the resulting floods will menace heavily populated downstream areas. And the cloud's driving up temperatures in the Himalayas at twice the rate predicted by global warming.

The study, reported today in the journal Nature, used drone aircraft to fly into the smog and study its effects. The cloud consists of dangerous particles generated by both industrialized power sources and low-tech fires fueled by wood and dung. The particles stay in the air for only about 3 weeks, though, which means quick action is possible. (More smog stories.)