Black Carbon Takes No. 2 Spot In Climate Change Agents

31 atmospheric scientists have written a new study on the major component of soot called 'black carbon', long identified with causing respiratory problems - and have shown how it is the 2nd most important agent of climate change after carbon dioxide.
January 18, 2013, 6am PST | Irvin Dawid
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The study, "Bounding the role of black carbon in the climate system: A scientific assessment" was published online Jan. 15 by The Journal of Geophysical Research-Atmospheres.  Elisabeth Rosenthal writes that the new research doubles the "black carbon heat-trapping power" (from the ) last major report by the United Nations’ Intergovernmental Panel on Climate Change, in 2007."

The new calculation adds urgency to efforts to curb the production of black carbon, which is released primarily by diesel engines in the industrialized world and by primitive cook stoves and kerosene lamps in poorer nations. Natural phenomena like forest fires also produce it.

Carbon dioxide, the leading greenhouse gas, remains in the atmosphere for decades and is distributed nearly uniformly across the earth’s atmosphere. By contrast, black carbon generally only persists in the air for a week to 10 days, so its presence across the globe is far more variable.

The importance of black carbon as a significant global warming contributor is not new - it was identified as a major contributor by  V. Ramanathan of Scripps Institution of Oceanography in San Diego in a 2008 study - but he described his position as "very lonely".  Now he's got lots of company.

PRI's The World’s environment editor Peter Thomson also reported on the new study (audio, podcast, and text available) and points to the burning of coal in addition to diesel emissions and wood smoke - in fact, the radio report opens with a reference to the 'Airpocalypse' in Beijing. Identifying black carbon as such as a major contributor to climate change should boost efforts to fight it, Thomson explains.

(C)ompared to the challenges of cutting carbon dioxide and methane pollution, which we’re clearly having a very hard time dealing with, getting rid of most of the world’s sources of soot would be a fairly simple fix. One of the authors of this study called it a “no-brainer.” And it could reduce the rate of warming of the atmosphere at least a bit and buy us some time while we deal with those bigger challenges.

MARCO WERMAN, moderator: And of course there’d be a big public health benefit I would imagine.

THOMSON: Yeah, that’s the second thing, and another reason that study author called getting rid of it a “no-brainer.” It’s kind of an environmental two-fer.

The Environmental Protection Agency does not list black carbon as a greenhouse gas. It states on its Global Emissions page, "Black carbon (BC) is a solid particle or aerosol, not a gas, but it also contributes to warming of the atmosphere. Learn more about BC and climate change on our Causes of Climate Change page."

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Published on Thursday, January 17, 2013 in The New York Times
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