The Asian brown cloud joins the Ozone Hole as a human-induced pollution phenomenon big enough to have its own name, and is another of the signs, along with the 'dead zone' in the Gulf of Mexico and the collapse of the Larsen B ice shelf in Antarctica, that scientists have been watching for as clear indications that human pollution of the Earth is getting out of hand. An enormous cloud of 'dynamically interacting' pollutants three kilometers thick in places, the Asian brown cloud is basically just smog, but smog that is not localized to a particular urban area (such as the well-known smog clouds of Los Angeles or Mexico City). Instead, the Asian brown cloud covers a vast area which includes the Northern Indian Ocean, and large parts of India, Pakistan, Afghanistan, Southeast Asia and China. The cloud has been collecting for three to four months every year for the last couple of decades, drastically affecting the climate of South Asia and directly or indirectly killing millions of people.

The cloud was first noticed in the 1980s by US pilots flying across the Indian Ocean, and when scientists first began making a serious study of it, they didn't know how bad it was. They thought, based on their knowledge of similar phenomena around the world, that it would be confined to the major cities, and that it would be similar in makeup to smog in other parts of the world. However, a major study (INODEX, the Indian Ocean Experiment), commissioned by the UN and involving 250 experts from around the world has just been completed, which reveals the amazing extent and threat of the cloud, which contains unusual amounts of 'heavy' pollutants such as soot, ash and other black carbon aerosols.

The area surrounding the Indian Ocean, where the cloud is centred, is home to roughly 3 billion people, fully half the world's population and a number which is only going to rise over the coming decades. The vast number of people has led to massive urban overcrowding and crippling poverty, which in turn has led to pollution on an enormous scale. Industries in most South Asian cities cannot afford to burn clean, energy-efficient fuel, and are relying on old technology and fuels which have been largely abandoned by the wealthier Western economies. Also, a significant contributor to the brown cloud is 'biomass burning', the burning of organic matter either deliberately or accidentally through, for example, forest fires and fossil fuels - apparently a large part of the pollutants come from people using cow dung and kerosene to power old-fashioned ovens and cookers.

The effect of the cloud on climates all around South Asia is horrific. It is estimated that it could be responsible for up to a million deaths from respiratory diseases every year, with the worst time being the winter, when air temperature is higher than ground temperature, trapping the pollutants in the atmosphere. Some scientists involved in INODEX, including Nobel Laureate Paul Crutzen, believe that the figure could be as high as two million deaths a year. The brown cloud blocks 10-15% of sunlight reaching the ground, causing a periodic massive alteration in the region's climate, which has led to floods, droughts, storms and similarly unpredictable weather phenomena all over the affected region. Many of these effects may have been attributed to other factors, such as global warming in general, or El Nino. The brown cloud also causes acid rain, which is affecting agriculture and may be destroying as much as 10% of India's rice harvest in the winter. The cloud is also reducing rainfall over Pakistan, Afghanistan, western China and some parts of central Asia, causing severe droughts and crop failures.

In another disturbing development, scientists discovered that the cloud can travel. They tracked the haze as it migrated along the line of a prevailing wind to the Maldives, where it also cut sunlight and caused acid rain, and they stated that parts of the cloud could be carried around the entire globe in less than one week. Environmental studies always attract more attention if people in Western developed nations feel that their lifestyles might be under threat, and this may be the reason why this study has hit the headlines in almost every newspaper worldwide today (August 12th, 2002). CNN has carried it prominently, possibly because they are so happy to be able to report a global environmental problem for which the US is not responsible.

INODEX has released its results two weeks before the Earth Summit in Johannesburg on August 26th, hoping to draw attention to the plight of people living under the Asian brown cloud, and to stimulate world leaders to do something about it before it gets even worse. Apparently, due to the nature of the pollutants, it is not too late to bring the region's climate back from the brink. Aerosol pollutants such as soot and ash, which form a huge part of the brown cloud, are naturally drawn down out of the atmosphere by rain, which means that the cloud will be dispersed if it is not being continually added to. However, the social change involved in altering the fuel-burning strategies of the affected areas would be staggering, and would require enormous financial aid from the wealthier nations of the world. Given the environmental record to date of the world's wealthiest nations, and the attitude of countries such as the US of "OK, we'll stop polluting, unless we're making money from it, in which case fuck you", I wouldn't hold your breath. Get it? Ha ha.

http://www.cnn.com/2002/WORLD/asiapcf/south/08/12/asia.haze/index.html
http://www.sciencenetlinks.com/sci_update.cfm?DocID=82

Also known as the "Great Pall Of China", the brown cloud is extensively fueled by China's coal fire problem.

Each year in China, an estimated 100-200 million tons of coal is lost to spontaneous combustion - five to ten times the amount of Chinese coal export. The fires are very difficult to put out, as they are spread over a 5000 km by 700 km area. Some of the fires are estimated to date back to the Pleistocene Era.

The fires are thought to contribute 2-3% of the total world carbon dioxide production due to fossil fuels and significantly add to the brown cloud.

Source: International Institute for Geo-Information Science and Earth Observation, http://www.itc.nl/

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