After carbon dioxide, the second largest contributor to global warming is ordinary soot, according to new research published Sunday in Nature Geoscience. So-called "black carbon" has up to 60 percent the warming effects of the more oft-noted culprit CO2.
The implication is fairly radical: Quickly reducing soot could have substantial short-term effects on the rate of climate change. Whereas CO2 molecules stay in that atmosphere for years, soot particles stay about a week.
(In 2006, U.S. EPA’s Stephen Johnson released soot standards substantially weaker than his scientific advisers recommended.)
Since 40 percent of soot comes from power sources, mainly coal and oil, that also produce CO2, measures to reduce soot would likely reduce other GHGs as well.
The other 60 percent comes from burning biomass, mainly in the developing world, where a great deal of wood is burned for heating and cooking and forests are burned to clear them for agriculture.
Reducing soot requires no new technology, only tighter regulations and better financing instruments.
This seems like a gimme of an investment. Approximately 400,000 people a year die prematurely from inhaling soot. Some of those lives could be saved and some precious time could be bought for longer term climate solutions — probably at a net financial gain. Perhaps Congress should take note
(Integrating observed data from satellites and surface instruments, along with information from a range of previous studies, researchers found that soot’s forcing effect on the atmosphere is about 0.9 watts per meter squared. Last year’s IPCC report, by contrast, estimated a range from 0.2 to 0.4 w/m2 — woefully conservative, if this study is right.)