Asia: — U.S.scientists say clouds of man-made haze that blanket southern and eastern Asiaare helping accelerate the melting of the Himalayan glaciers. VOA’s Heda Bayronreports from our Asia News Center in Hong Kong on the effect of these so-called”brown clouds” on the region’s climate.
A team from the Scripps Institution of Oceanography in California usedunmanned aircraft to measure heat in the atmosphere high above the Indian Ocean,a part of Asia often blanketed by “brown clouds” of man-made pollution.
Photo: Chengdu, China is covered in a heavy haze, caused by tons of dry stalks burning on the city’s outskirts, 10 May 2007 Brown clouds are known to cool the land or sea below them because they trapsunlight, not allowing it through to the earth below. Until now, however, littlehas been known about the clouds’ effect on the air immediately around them.
The Scripps team found that the brown clouds increased the heat of the airaround them by around 50 percent. The team says the clouds have contributedroughly half of the temperature increase that has been blamed for the melting ofthe Himalayan glaciers.
“What we discovered from our measurement was the brown cloud wasabsorbing a lot of sunlight and was contributing to heating of the air,”said V. Ramanathan, the chief scientist of the research team. “We put thisdata in a climate model and that model suggested that the brown cloud’s solarheating was contributing to glacial melt.”
Brown clouds are made up of tiny particles called aerosols that come from,among other things, forest fires, vehicle and industrial emissions, and theburning of wood and cow dung for cooking that is common in many households indeveloping Asia.
“It’s basically the smoke,” said Ramanathan. “The smokecarries these particles, and the atmospheric winds transport it so that we see[in] satellite data the brown cloud covering [the] entire South Asia and EastAsia region and go over the ocean so that they intercept sunlight and modify theclimate.”
Experts say the loss of the Himalayan glaciers could mean water shortages formillions in Asia. The glaciers of the Tibetan plateau are the main source of theregion’s major rivers such as China’s Yellow River, Southeast Asia’s Mekong andIndia’s Ganges.
In May, Greenpeace in China said Mount Everest was heating up at triple theworld’s average. Some scientists say at the current rate of warming, theHimalayan glaciers could disappear by 2035.
Ramanathan says one way to reduce brown clouds is to start usingsolar-powered cookers in millions of Asian households.