Thursday, April 4, 2013

Soot Contributes to Global Warming

According to recent research, the second-most significant contributor to global warming (after carbon dioxide), is not methane, as previously thought.  It’s carbon-black, also known as soot.  Black soot contributes to global temperature by absorbing sunlight and converting it to heat.  Soot is especially damaging when it falls on frozen and snow-covered regions of the Earth, because it causes snow and ice to melt more rapidly than they would otherwise.  Soot may be the reason why arctic ice is melting much faster than most climate models had predicted, based on elevations of greenhouse gases alone.

The good news is that correcting the climate problem caused by soot would be easier than dealing with methane and carbon dioxide.  Soot is a solid, so it is removed from the atmosphere much more quickly than either methane or carbon dioxide.  Within weeks of soot’s emission, it simply falls to the surface of the earth, whereas carbon dioxide and methane may hang around in the atmosphere for years.  In addition, most of the soot comes from diesel engines, inefficient stoves, and dirty diesel fuel; all problems that could be dealt with fairly easily if we had the will to do so.  Improving the efficiency of diesel engines to reduce soot emissions would have a significant impact within weeks.

You can read the entire comprehensive study of soot and its role in climate change in the Journal of Geophysical Research: Atmospheres.  But I warn you; it’s 286 pages long!  For a quick look, read the abstract.

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