NEW DELHI--A giant cloud of pollution is hanging over large parts of South Asia, endangering the health of over a billion people who inhabit the region, according to a report released yesterday by the United Nations Environment Programme (UNEP).
The findings provide evidence that a 3-kilometer-deep blanket of pollution--a mass of ash, acids, aerosols, and other particles--is disrupting weather systems in western Asia. According to the report, sulfate and other aerosols reflect sunlight and reduce the amount of solar energy hitting Earth's surface by as much as 15%. At the same time, carbon soot and other compounds absorb heat, warming the lower parts of the atmosphere. This combination of cooling and heating may be altering the winter monsoon. If so, more rain would drench the eastern coast of Asia. At the same time, declines in rainfall of up to 40% would hit northwest India, Pakistan, Afghanistan, western China, and neighboring western-central Asia.
The pollution could lead to "several hundreds of thousands" of premature deaths from respiratory diseases, the report suggests. Results from seven cities in India alone, including Ahmedabad, Kolkata, Delhi, and Mumbai, estimate that air pollution was responsible for 24,000 deaths annually in the early 1990s. By the mid-1990s that number rose to 37,000.
The pollution and its impact was described by 200 scientists working on the Indian Ocean Experiment, supplemented by new satellite data and computer modeling. The report also suggests the causes of the miasma: "The haze is the result of forest fires, the burning of agricultural wastes, dramatic increases in the burning of fossil fuels in vehicles, industries, and power stations, and emissions from millions of inefficient cookers burning wood, cow dung, and other 'bio fuels,' " says Klaus Toepfer, executive director of UNEP.
"The data are of very high quality and the evidence is convincing"; the results should be "taken seriously," says Jay Fein, program director of climate dynamics at the U.S. National Science Foundation.