Cloud of Soot Above Asia Is Affecting Cities, U.N. Says

BEIJING -- A three-kilometer thick cloud of brown soot and other pollutants hanging over Asia is darkening cities, killing thousands and damaging crops but might be holding off the worst effects of global warming, the United Nations said Thursday.
The vast plume of contamination from factories, fires, cars and deforestation contains some particles that reflect sunlight away from the earth, cutting its ability to heat the earth.
"One of the impacts of this atmospheric brown cloud has been to mask the true nature of global warming on our planet," U.N. Environment Program head Achim Steiner said at the launch in Beijing of a report on the phenomenon.
It said the amount of sunlight reaching earth through the murk has fallen by up to a quarter in the worst-affected areas and if the brown cloud disperses, global temperatures could rise by up to two degrees Celsius.
But the overall effect of slowing climate change isn't the silver lining to a dark cloud that it appears to be. The choking soup of pollutants might hold temperatures down overall, but the mix of particles means it is also speeding up warming in some of the most vulnerable areas and exacerbating the most devastating effects of higher temperatures.
According to the report, the complex impact of the cloud, which tends to cool areas near the surface of the earth and warm the air higher up, is believed to be causing a shortening of the monsoon season in India while increasing flooding there and in southern China.