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.

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."

Full Story: Burning Fuel Particles Do More Damage to Climate Than Thought, Study Says



Irvin Dawid's picture

Economist chimes in....the project name is indicated

From the Jan 19 print edition: Global warming: The new black:
"Soot is even worse for the climate than was previously thought"

The article notes the proper name for the research by the '31 scientists', i.e. that they worked under an actual project name, the "International Global Atmospheric Chemistry Project".

"This study, a four-year affair conducted under the auspices of the International Global Atmospheric Chemistry Project, an umbrella group for research into such matters, is based on a lot more information about soot than was previously available, and a better understanding of how it affects the climate."

In addition, the article indicates that the prior UN study on soot's effects was done by the United Nations Environment Programme (UNEP). NYT had listed IPCC.

But perhaps the most important message to air quality and climate activists is to focus on diesel emissions - either cleaning or eradicating them as they are the source of 70% of soot emissions in Europe and "the Americas":

"It might seem that the new study is one more item of bad environmental news. Not so. It should be easier to deal with black carbon than with carbon dioxide. Whereas CO2 is long-lasting and an inevitable by-product of burning fossil fuels, soot drops out of the atmosphere within weeks. Stop putting it there and it will rapidly go away—a potentially easy win.

That win is made easier still by the fact that about 70% of emissions in Europe and the Americas come from diesel engines. Better exhausts, to trap carbon particles before they are emitted, and the scrapping of old, highly polluting vehicles could make an immediate impact. In other countries the problem is more often inefficient stoves and dirty fuel—again, things that are easy to deal with, at least in principle."

Irvin Dawid's picture

Does EPA accept acknowledge the new study?

"On November 14, 2012, EPA hosted the Black Carbon Symposium in San Francisco. The purpose of this meeting was to share the latest scientific advancements on black carbon public health, climate, and air quality impacts. The symposium featured several experts on black carbon to explain the basic science of black carbon and its effects on human health and global climate change...."

See numerous "conference documents" on right-hand side of webpage.

It is not clear to me that the International Global Atmospheric Chemistry Project study is acknowledged by EPA.

I also question the "70%" figure for diesel emissions on black carbon sources indicated in below Economist article - coal power plants would seen to be a major contributor

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