Found this via CSR Asia: The pollution-filled brown clouds covering South Asia enhance the solar heating of the lower atmosphere by 50%, according to this report:
The team led by Scripps atmospheric chemistry professor V. Ramanathan describes findings that atmospheric brown clouds enhanced solar heating of the lower atmosphere by about 50 percent in a paper to be released in the Aug. 2 edition of the journal Nature.
The combined heating effect of greenhouse gases and the brown clouds, which contain soot, trace metals and other particles from a growing cadre of urban, industrial and agricultural sources, is enough to account for the retreat of Himalayan glaciers observed in the past half century, the researchers concluded. The glaciers supply water to major Asian rivers including the Yangtze, Ganges and Indus.
These rivers in turn comprise the chief water supply for billions of people in China, India and other south Asian countries.
“The rapid melting of these glaciers, the third-largest ice mass on the planet, if it becomes widespread and continues for several more decades, will have unprecedented downstream effects on southern and eastern Asia,� the Nature article concluded.
That’s not just the Yangtze, Ganges and Indus, but also the Brahmaputra, Irrawaddy, Salween, Mekong and Yellow rivers that will be affected. And those are only the big ones that I can think of just off the top of my head. Check a map, that’s a huge, huge slice of Asia affected, from Pakistan right across South Asia to Southeast Asia then up to China.
The study was conducted in the Maldives, but it’s kinda confusing:
The scientists based their conclusions in large part on data gathered by a fleet of unmanned aircraft during a landmark field campaign conducted in March 2006 in the skies over the Maldives, an island nation in the Indian Ocean south of India. The Maldives Autonomous unmanned aerial vehicle Campaign (MAC) took place during the region’s dry season when polluted air masses travel south from the continent to the Indian Ocean. The air typically contains particles released from industrial and vehicle emissions as well as through biomass burning.
Such polluted air has been demonstrated to have a dual effect of warming the atmosphere as particles absorb sunlight and of cooling the earth’s surface as the particles curb the amount of sunlight that reaches the ground. The net effect of the two forces remains uncertain but other research by Ramanathan has suggested that the surface dimming might serve to mask global warming, leading scientists and the public to underappreciate the full magnitude of anthropogenic climate change.
It’s not clear to me how they concluded that the brown clouds were enhancing global warming, but in the article the scientists insisted that was true. I guess I’m missing some important background information here.
But apparently it’s not all doom and gloom:
Now a new analysis of pollution-filled “brown clouds� over south Asia by researchers at Scripps Institution of Oceanography at UC San Diego offers hope that the region may be able to arrest some of the alarming retreat of such glaciers by reducing its air pollution.
Oh? So where are these rays of hope?
The new findings should spur the international community to ever greater action, in particular at the next crucial climate change convention meeting in Indonesia this December. For it is likely that in curbing greenhouse gases we can tackle the twin challenges of climate change and brown clouds and in doing so, reap wider benefits from reduced air pollution to improved agricultural yields
So says Achim Steiner, according to this article. So, judging by humanity’s historic record, it is all doom and gloom.
