They call it the Asian Brown Cloud. Anyone who has flown over South Asia has seen it – a vast blanket of smog that covers much of the region.
It is also what colours those sunsets at the Taj Mahal. Now a group of scientists has carried out the first detailed study of the phenomenon and arrived at a troubling conclusion.
They say that it is causing Himalayan glaciers to melt, with potentially devastating consequences for more than two billion people in India, China, Bangladesh and other downstream countries.
In a study published yesterday by Nature, the British journal, they say that black soot particles in the cloud are absorbing the Sun’s heat and pushing up temperatures at the same altitude as most Himalayan glaciers.
Scientists have already observed that two thirds of the 46,000 glaciers in the Himalayas are shrinking, leading to increasingly severe floods downstream and, eventually, to widespread drought. Greenhouse gases were previously thought to be the main cause of the problem, which threatens the sources of Asia’s nine main rivers – including the Indus, the Ganges and the Yangtze.
But the research team from the Scripps Institution of Oceanography in California says that the Asian Brown Cloud – made up of gases and suspended particles known as aerosols – is just as much to blame. “My one hope is that this finding will intensify the focus of Asian scientists and policy makers on the glacier issue,” Veerabhadran Ramanathan, who led the research, told The Times. “These glaciers are the source for major river systems, so at least two billion people are directly involved in this.”
Friday, August 3, 2007
Is AGW causing the Himalayan glaciers to melt?
There is no doubt that many of the Himilayan glaciers are receding. The alarmists are quick to point to this as proof that human-produced CO2 emissions are warming the planet. A new study, though, indicates that while the alarmists got the "human-produced" part right, the actual culprit in the melting of Asian glaciers is good old-fashioned smog (The Times (UK), August 3):