Global Warming: Black Carbon 2nd Only to Carbon Dioxide

A new study finds that black carbon (soot) is warming the climate about twice as fast as scientists had estimated (1,2)). The burning of everything from oil in ship and truck diesel engines to coal in power plants produces eight million tons of soot each year. Soot absorbs sunlight, shrinks cloud droplets and brightens them, and darkens ice and snow. Soot adds 1.1 watts per square meter (W/m2) to the climate system. It is second only to carbon dioxide, the dominant greenhouse gas forcing warming, which accounts for 1.66 W/m2. REFERENCES: (1) T. C. Bond plus 31 authors from 9 countries. ``Bounding the role of black carbon in the climate system: A scientific assessment.'' January 2013. American Geophysical Union. doi: 10.1002/jgrd.50171. (2) Richard A. Kerr. ``Soot Is Warming the World Even More Than Thought.'' Science. 25 January 2013: Vol. 339 no. 6118 p. 382. DOI: 10.1126/science.339.6118.382.