Asian brown cloud

The Asian brown cloud is a layer of air pollution that covers parts of the northern Indian Ocean, India, Pakistan, and parts of South Asia, Southwest Asia, and China. [cite journal
last=Srinivasan
first=J
title=Asian Brown Cloud – fact and fantasy|journal=Current Science
volume=83|issue=5
url=http://www.ias.ac.in/currsci/sep102002/586.pdf
year=2002|month=September|day=10|pages=586–592] [cite journal
last=Ramanathan
first=Veerabhadran
title=Indian Ocean experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze
journal=Journal of Geophysical Research
volume=106|issue=D22
url=http://www.agu.org/pubs/crossref/2001/2001JD900133.shtml
year=2001|pages=28371–28398
doi=10.1029/2001JD900133] Viewed from satellite photos, the Cloud appears as a giant brown stain hanging in the air over much of Asia and the Indian Ocean.

Causes

In some humidity conditions, it forms haze. It is created by a range of airborne particles and pollutants (e.g. woodfires, cars, and factories), characteristic of biomass burning and industrial emissions due to incomplete burning. [cite journal|last=Taylor|first=David|title=The ABCs of Haze|journal=Environmental Health Perspectives|volume=111|issue=1|url=http://www.ehponline.org/docs/2003/111-1/forum.html#thea|year=2003|month=January|day=1|pages=A20] The cloud is associated with winter monsoon (December to April) during which there is no rain to wash pollution from the air.

This pollution layer was observed during the Indian Ocean Experiment (INODEX) intensive field observation in 1999. Subsequently the United Nations Environment Programme (UNEP) has been supporting a project called ABC (still ongoing in 2007).

Although aerosol particles are generally associated with a global cooling effect, recent studies have shown that they can actually have a global warming effect in certain regions such as the Himalayas. [cite journal
last=Ramanathan
first=Veerabhadran
title=Warming trends in Asia amplified by brown cloud solar absorption
journal=Nature|volume=448
doi= 10.1038/nature06019
year=2007|month=August|day=2|pages=575–578] The warming effect of the Asian Brown Cloud may be an important factor in the retreat of the Himalayan glaciers. The United Nations Environment Program is worried that Asian glacial melting could lead to water shortages and floods for the hundreds of millions of people who live downstream.

A recent CSIRO study found that the Asian Brown Cloud is also affecting rainfall in Australia. [cite journal|last=Rotstayn|first=Leon|title=Have Australian rainfall and cloudiness increased due to the remote effects of Asian anthropogenic aerosols?|journal=Journal of Geophysical Research|volume=112|issue=D09202|url=http://www.agu.org/pubs/crossref/2007/2006JD007712.shtml|year=2007|month=May|day=2|doi=10.1029/2006JD007712|pages=D09202]

References

See also

*ASEAN Agreement on Transboundary Haze Pollution

External links

* [http://www.patriotfiles.com/ History]
* [http://www.rrcap.unep.org/issues/air/impactstudy/index.cfm UNEP Impact Study of the "Asian Brown Cloud"]
* [http://www.nasa.gov/vision/earth/environment/brown_cloud.html NASA Eyes Effects of a Giant 'Brown Cloud' Worldwide]
* [http://archives.cnn.com/2002/WORLD/asiapcf/south/08/12/asia.haze/ 'Asian Brown Cloud' poses global threat]
* [http://www-abc-asia.ucsd.edu/ABCProposal-Nov282001.pdf Project Proposal Project Asian Brown Cloud]