Atmospheric Brown Cloud

Our chat topic for 18 February 2006 was “Atmospheric Brown Cloud”(ABC)

No one came to the chat room.

Are we waiting for the cloud to enter our homes before we start thinking about it ?

The photographs in this article were taken at 8.30 AM in Gurgaon , India on a morning when minimum temperature was 17 degrees centigrade; Maximum 33 degrees. There could not be any fog or mist at this time and temperature. So what are these smog screens made of?

Here is some information, gleaned from newspapers and the internet. There is mounting evidence that the ABC dramatically reduces monsoon rain in the subcontinent.

It was called the ‘Asian Brown Cloud' in 2002, when a UN report first warned of this layer of pollution comprising ash, acids and aerosols. At that time, the two-mile thick haze extended ominously across the most densely populated areas of the world: southern, south-eastern, and eastern Asia . Subsequently, however, similar patterns were detected elsewhere in the world and it was renamed ‘Atmospheric Brown Cloud'.

Asia is particularly vulnerable as the ABC causes changes in the winter monsoon season, sharply reducing rain over northwestern parts of the continent and increasing rain along the eastern coast. This could potentially cut winter rice harvests by as much as 10 per cent. Research suggests that the impact of the haze will intensify over the next 20 years as the continent's population touches the 5 billion mark.

• large surface cooling due to reduced sunlight perturbs the hydrological cycle
• 75% of the cloud is man-made
• Cause forest fires, inefficient cooking fuels, factories and motor vehicle use
• Effect-less rain in northwest India , Pakistan , Afghanistan , and western PRC by as much as 40%
• acid deposition and plant damage and respiratory ailments

There are some very telling pictures from NASA at the following link.

http://www.nasa.gov/vision/earth/environment/brown_cloud.html

Some scientists were unhappy about the hue and cry raised over the ABB. It diverted attention from the developed to the developing countries, they felt. And the blame was shifted from prime greenhouse emitters like the U.S. to the Asian countries.

But the ABC can be controlled. Since aerosols have a short life span, their spread can be checked-by using cleaner fuels that burn efficiently and pollute less…

( Text and Photographs-Susan Sharma)