Gerard Wynn, PlanetArk 21 Feb 08;
MONACO - Air pollution is blotting out a tenth of China's sunlight and a similar amount in India, a leading US climate scientist said on Wednesday.
The soot, called black carbon and produced by burning coal, dung, wood and diesel, rises in the upper atmosphere, where it traps the sun's heat and blots out the light, raising the temperature at higher altitudes but cooling the earth below.
Veerabhadran Ramanathan, an atmospheric scientist at the University of California, said that as a result the soot is contributing to the melting of the glaciers and weakening Indian monsoons.
Himalayan glaciers supply water to hundreds of millions of people in China and India, and melting attributed to climate change is expected to affect supplies within 20 to 30 years.
"We found it (soot) was responsible for about half the warming," Ramanathan told Reuters on the fringes of the Monaco meeting of 100 environment ministers, hosted by the UN Environment Programme (UNEP).
The soot is also landing on the glaciers as a dark dust which makes the ice less reflective, speeding up melting.
Himalayan glaciers are warming twice as fast as Indian plains, he added.
One way to tackle the problem is to replace wood or dung for cooking with biogas or shiny metallic solar cookers.
In the meantime, soot emissions are rising in India and at best levelling off or rising in China, said Ramanathan, who also heads UNEP's Atmospheric Brown Cloud project, set up in 2001 to measure the impacts of soot and ash around the world.
Ramanathan estimates the loss of sunlight worldwide at under 3 percent since 1950, compared to recent studies showing 8-10 percent dimming in China and 7 percent less light over India.
By blotting out light, the smoke is cooling the Indian ocean, cutting evaporation and disrupting the monsoon, he said, and possibly altering airflows leading to drier weather in northern China.
"Of all the things we can do the dumbest is to cut out the sunlight. There's general acceptance now that there's something wrong with the Indian monsoon."
But cleaning the atmosphere and allowing in more sunlight would add about 1 degree centigrade to 0.8 degrees global warming happening already from carbon dioxide (CO2) emissions.
"This research is showing the urgency of bringing down CO2," Ramanathan said, adding that he wasn't convinced that global climate talks launched in December in Bali, Indonesia, would do enough to tackle the problem.
As a result he advocated research to determine the feasibility of technologies which manipulate the climate, for example scattering reflective particles in space to stop the Earth from cooking.
