Asian haze may be killing 500,000

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Asian haze may be killing 500,000

By Jill Lawless in London

12Aug02

A TWO-mile-thick blanket of pollution over South Asia, may be causing the

premature deaths of a half-million people in India each year, deadly

flooding in some areas and drought in others, scientists have said.

The biggest-ever scientific study of the phenomenon - the " Asian Brown

Cloud " - was sponsored by the UN.

It found the grimy cocktail of ash, soot, acids and other damaging airborne

particles was as much the result of low-tech polluters like wood and

dung-burning stoves, cooking fires and forest clearing as it was of dirty

industries.

" When you think about air pollution, many people think of industry and

fossil fuels as the only causes, " report co-author Crutzen, a scientist

at the Max-Planck Institute for Chemistry in Mainz, Germany, told a news

conference in London.

" Biomass burning " , including forest fires and the burning of vegetation to

clear land or to warm the homes of poor people, was often ignored, he said.

More than 200 scientists contributed to the study, overseen by the UN

Environment Program in preparation for the World Summit on sustainable

Development opening on August 26 in Johannesburg, South Africa.

They used data from ships, planes and satellites to study Asia's haze from

1995 to 2000.

The report says respiratory illness appears to be increasing along with the

pollution in densely populated South Asia, with one study suggesting 500,000

premature deaths annually in India.

The dense cloud of pollution - also caused by auto emissions, factories and

waste incineration - cuts the amount of sunlight reaching the ground and the

oceans by 10 to 15 per cent, cooling the land and water while heating the

atmosphere.

That phenomenon appears to have altered the region's monsoon rains -

increasing rainfall and flooding in Bangladesh, Nepal and northeastern

India, while cutting back needed seasonal precipitation in Pakistan and

northwestern India.

Floods, drought, sunlight reduction and acid rain can all hurt agricultural

yields, and the report indicates the pollution may be cutting India's winter

rice harvest by as much as 10 per cent.

Veerabhadran Ramanathan, of the Scripps Institution of Oceanography in La

Jolla, California, one of the report's authors, said the extent of the

sunlight loss was " a major surprise " .

Scientists have warned it is too early to draw definite conclusions about

the impact of the cloud, and of similar hazes over East Asia, South America

and Africa.

" We need much more basic scientific data to be able to establish what are

the consequences for human health and the environment, " said Crutzen,

co-winner of the 1995 Nobel chemistry prize for his work on the ozone layer.

But the impact could be global since prevailing winds push pollution clouds

halfway round the world in just a week's time.

For many years, scientists believed only lighter greenhouse gases - such as

carbon dioxide that is produced from burning fossil fuels such as gasoline

and oil - were global in reach and effect.

They now say microscopic, suspended particles of pollutants - generically

called aerosols by atmospheric scientists - also travel the globe.

It is unclear what the haze's relationship is to global warming, which most

scientists believe is caused by the emission of greenhouse gases that trap

the Earth's heat. The pollution cloud appears to cool the area below by

blocking sunlight.

Klaus Toepfer, executive director of the UN Environment Program, said

scientists and policy-makers " should avoid making premature final

assessments " , but should start trying to cut pollution by introducing more

efficient heating stoves in developing countries and turning to solar power

and other clean sources of energy.

The environmental group Friends of the Earth said " urgent action is

desperately needed to tackle the causes behind this huge toxic cloud " .

" Actions must include phasing out fossil fuels and replacing them with

clean, green, renewable energy, and tough laws to protect the world's

forests, " said the group's climate co-ordinator, Kate Hampton.

Ramanathan said the surprises found by the study would drive scientists to

keep studying human impact on the environment.

" We've been looking at environmental issues for the last several decades,

yet the Asian haze came as a major surprise to us, " he said. " We don't know

how many more surprises we will find. "

This report appears on news.com.au.