Soot has greater climate impact than previously thought

ANN ARBOR-Black carbon, or soot, is the second largest human-caused contributor to global warming, according to a landmark study published today that involves a University of Michigan researcher. Behind only carbon dioxide in terms of its influence on the climate, the impacts of black carbon have been greatly underestimated, the researchers say. Their study, published in the Journal of Geophysical Research-Atmospheres, is the first quantitative and comprehensive analysis of this issue. Major sources of soot include diesel engines, wood and coal burning in small household burners and some industrial processes. " There are exciting opportunities to cool climate by reducing soot emissions but it is not straightforward. " -Piers Forster The report's estimate of black carbon's direct climate influence is about a factor of two higher than most previous work. Accounting for all of the ways it can affect climate, black carbon is believed to have a warming effect of about 1.