90% of Himalayan Glacier Melting Caused by Aerosols & Black Carbon
photo: Wonker via flickr.
We've reported a number of times on the growing body of knowledge pointing to aerosols being a greater component of climate change than previously thought, and to black carbon soot accelerating Himalayan glacier melting. Well, some new research from the Lawrence Berkeley National Laboratory quantifies that effect a bit more: Surabi Menon told Space Daily,
Our simulations showed greenhouse gases alone are not nearly enough to be responsible for the snow melt. Most of the change in snow and ice cover--about 90% of it--is from aerosols. Black carbon alone contributes at least 30% of this sum.
Black Carbon's Influence May Be Even Greater Than That...
The article goes on to caution that black carbon may be an even larger contributor than that though--perhaps as much as four times higher Menon says--because data inventories used in the simulations report less black carbon than what has been measured at several monitoring stations in India.Unfortunately though, this measured data is not complete enough to be incorporated into these particular climate models.
Black carbon is a problem because it 1) absorbs sunlight, warming the atmosphere, and 2) when it falls on the snow it changes the albedo of the surface, allowing it to absorb more sunlight and accelerates melting.
Weather Patterns Also Affected by Soot
It also has an effect on weather patterns, due to its warming of the atmosphere. Menon's study shows that it changes precipitation patterns and is "a major factor in triggering extreme weather in eastern India and Bangladesh." It also contributes to decreases in rainfall in central India.
If this all sounds like bad news that's because in many ways it is. Black carbon pollution increased in India by 46% from 1990-2000 and by a further 51% from 2000-2010. And this doesn't include black carbon pollution originating in China.
Remove the Pollution Source Cleans Up Problem Quickly
However there is a definite silver lining to this sooty cloud. Unlike carbon dioxide, methane and other greenhouse gases, black carbon comes out of the atmosphere comparatively quickly once the source of pollution is removed.
The sources of this pollution are increased burning of coal, inefficient cookstoves, older vehicle engines, shipping. Clean up these--replacing cookstoves is perhaps an overlooked line of attack here--and a major contributor to glacier melting is removed. Not to mention benefits to human health as air quality is improved.
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