Asian haze may be killing 500,000 By Jill Lawless in London, new.com.au 12 Aug 2002
A TWO-mile-thick blanket of pollution over South Asia, may be causing thepremature deaths of a half-million people in India each year, deadly flooding insome areas and drought in others, scientists have said.
The biggest-ever scientific study of the phenomenon – the “Asian BrownCloud” – was sponsored by the UN. It found the grimy cocktail of ash, soot, acids and other damaging airborneparticles was as much the result of low-tech polluters like wood anddung-burning stoves, cooking fires and forest clearing as it was of dirtyindustries. “When you think about air pollution, many people think of industry andfossil fuels as the only causes,” report co-author Paul Crutzen, ascientist at the Max-Planck Institute for Chemistry in Mainz, Germany, told anews conference in London. “Biomass burning”, including forest fires and the burning ofvegetation 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 UNEnvironment Program in preparation for the World Summit on sustainableDevelopment opening on August 26 in Johannesburg, South Africa. They used data from ships, planes and satellites to study Asia’s haze from 1995to 2000. The report says respiratory illness appears to be increasing along with thepollution in densely populated South Asia, with one study suggesting 500,000premature deaths annually in India. The dense cloud of pollution also caused by auto emissions, factories andwaste incineration cuts the amount of sunlight reaching the ground and theoceans by 10 to 15 per cent, cooling the land and water while heating theatmosphere. 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 northwesternIndia. Floods, drought, sunlight reduction and acid rain can all hurt agriculturalyields, and the report indicates the pollution may be cutting India’s winterrice 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 losswas “a major surprise”. Scientists have warned it is too early to draw definite conclusions about theimpact of the cloud, and of similar hazes over East Asia, South America andAfrica. “We need much more basic scientific data to be able to establish what arethe 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 cloudshalfway round the world in just a week’s time. For many years, scientists believed only lighter greenhouse gases such ascarbon dioxide that is produced from burning fossil fuels such as gasoline andoil were global in reach and effect. They now say microscopic, suspended particles of pollutants genericallycalled aerosols by atmospheric scientists also travel the globe. It is unclear what the haze’s relationship is to global warming, which mostscientists believe is caused by the emission of greenhouse gases that trap theEarth’s heat. The pollution cloud appears to cool the area below by blockingsunlight. Klaus Toepfer, executive director of the UN Environment Program, said scientistsand policy-makers “should avoid making premature final assessments”,but should start trying to cut pollution by introducing more efficient heatingstoves in developing countries and turning to solar power and other cleansources of energy. The environmental group Friends of the Earth said “urgent action isdesperately needed to tackle the causes behind this huge toxic cloud”. “Actions must include phasing out fossil fuels and replacing them withclean, green, renewable energy, and tough laws to protect the world’sforests,” said the group’s climate co-ordinator, Kate Hampton. Ramanathan said the surprises found by the study would drive scientists to keepstudying 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’tknow how many more surprises we will find.”