Asian Brown Cl0ud

Perhaps the most famous pall of pollution anywhere in the world sits over India. The so-called Asian Brown Cloud is the combined product of thousands of coal-burning power stations, tens of thousands of factories and millions of open fires burning biomass like wood and dung, and now a semipermanent feature of the South Asian meteorological map. By reducing solar radiation at the surface, it has cooled the entire north Indian Ocean and changed the dynamics of monsoon, perhaps the world's most spectacular and important meteorological phenomenon. At its height in the spring, the brown cloud creeps north up to the ramparts of the high Nepali Himalaya, its sooty deposits darkening the now snow on the flanks of Mount Everest itself.

If China is included too, rapidly industralising Asia is the densest source of global pollutants. Scientists at high-altitude monitoring sites on Mauna Loa volcano in Hawaii, and in Boulder, Colorado, in the Rockies, puzzles at first by the rising levels of sulfur their leaser measurement found in the stratosphere, have discovered that reaching the high stratosphere. .......

Those who suffer most from the direct impacts of this pollution, of course, are those living in Asia. Airborne particulates are a leading cause of heart and lung disease throughout the continent, where three billion people breathe air classed as dangerous by the World Health Organization. The Chinese Academy for Environmental Planning blames air pollution for 411,000 premature deaths each year across the country, probably a serious underestimate given the year-round smog pall hanging over most Chinese cities. .....

....... First, it seems a 10 percent drop in sunshine reaching the ocean lowers the level of evaporation, reducing the moisture available for rainfall. First, it seems, a 10 percent drop in sunshine reaching the ocean lowers the level of evaporation, reducing the moisture available for rainfall. Second, the Asian brown cloud -- thickest over the densely populated landmass of India -- also reduces the temperature difference between land and sea that is the main engine of the monsoon. The differing inputs on the northern and southern Indian Oceans -- where the northern half cools, and the southern half, which remains under relatively clean air, warms -- also hampers the monsoon circulation. Over much of India, Bangladesh, Burma, and Thailand summer monsoon rainfall has been declining as brown-cloud aerosols weaken circulation patterns that sustain the food production and livelihoods of over a billion people across the subcontinent. .... Page 184 / 185