ENVIRONMENT: Brown Cloud Begins to Choke Asia

By Sanjay Suri Reprint | | Print |

Sanjay Suri

LONDON, Aug 14 2002 (IPS) - Much of Asia is beginning to choke under a vast three-kilometre high cloud, according to a major new study led by the United Nations Environmental Programme.

The Asian Brown Cloud, as the scientists call it, is “damaging agriculture, modifying rainfall patterns including those of the mighty Monsoon and putting hundreds of thousands of people at risk,” says the report released in London Monday.

The findings arise from a 40-million dollar study conducted between 1995 and 1999 by about 200 scientists working on the Indian Ocean Experiment (INDOEX). The scientists collected data using aircraft, ships and satellites.

Preliminary results indicate that the build up of the haze, a mass of ash, acids, aerosols and other particles, is disrupting monsoons and triggering droughts in western parts of the Asian continent. “The concern is that the regional and global impacts of the haze are set to intensify over the next 30 years as the population of the Asian region rises to an estimated five billion people,” the report says.

The findings indicate that “the spectacular economic growth seen in this part of the world in the past decade may soon falter as a result.”

“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 the United Nations Environmental Programme (UNEP).

“More research is needed, but these initial findings clearly indicate that this growing cocktail of soot, particles, aerosols and other pollutants are becoming a major environmental hazard for Asia,” he says. “There are also global implications, not least because a pollution parcel like this can travel half way around the globe in a week.”

The massive brown cloud is reducing the amount of sunlight reaching the earth’s surface in this area by 10 to 15 per cent, Prof V. Ramanathan from the Scripps Institute of Oceanography told reporters. But heat absorbed by the particles is warming the lower parts of the atmosphere, he said.

“This combination of surface cooling and lower atmosphere heating appears to be altering the winter monsoon leading to a sharp fall in rainfall over north-western parts of Asia and increase of rainfall along the eastern coast of Asia,” the report says.

The aerosols and particles in the haze are also affecting rainfall in other ways, the report says. “Raindrops are becoming smaller and more numerous, triggering less frequent rainfall and longer-lived clouds,” it says. “One consequence is to move precipitation away from populated regions.”

The disruption to the monsoons is leading to reduced agricultural output, the report says.

Less sunlight on the earth’s surface means less evaporation, and therefore less cloud formation and rainfall, Prof Ramanathan said. In addition, “reduced sunlight is also reducing photosynthesis, and therefore productivity.”

According to research in India, the haze may be reducing the winter harvests by as much as 10 per cent. “Acids in the haze may, by falling as acid rain, have the potential to damage crops and trees,” the report says. “Ash falling on leaves can aggravate the impacts of reduced sunlight on the earth’s surface.”

The pollution that is forming the haze could be leading to more than half a million deaths as a result of higher levels of respiratory diseases, the report says. “Studies indicate that the level of fatalities is rising along with the levels of pollution,” it says.

“We have seen for some time that the sky over this region has been hazy, but we did not expect the problem to be of this magnitude,” Prof Ramanathan told reporters. The INDOEX experiment is the first to study it systematically.

“The global models used in the report suggest that the haze may reduce precipitation over north-west India, Pakistan, Afghanistan, western China and the neighbouring western central Asian region by between 20 per cent and 40 per cent,” the report says.

One should not ignore the recent developments. “There have been two consecutive droughts in 1999 and 2000 in Pakistan and the north-western parts of India while increased flooding in the high rainfall areas of Bangladesh, Nepal and the north-eastern states of India.”

The study says its findings are of a preliminary nature, and are limited by the fact that most studies were carried out between December and April. The research is also trying to unravel links between the haze and its impacts on global warming.

“But there is a silver lining to the cloud,” said Prof Ramanathan. “The problem can be addressed relatively soon if the necessary policy decisions can be taken.”

ENVIRONMENT: Brown Cloud Begins to Choke Asia

By Sanjay Suri Reprint | | Print |

Sanjay Suri

LONDON, Aug 13 2002 (IPS) - Much of Asia is beginning to choke under a vast three-kilometre high cloud, according to a major new study led by the United Nations Environmental Programme.
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