Published in the September 27 issue of the journal Science, the report -- by researchers from NASA's Goddard Institute for Space Studies -- suggests that by absorbing sunlight and altering weather patterns, light absorbing carbon-based particles could have nearly as much impact on global warming as carbon dioixide: a greenhouse gas that has long been considered the primary culprit in global warming. The soot particles are produced by diesel engines, cooking fires and other sources.
In a perspectives article published with the NASA Goddard paper, atmospheric researchers from the Georgia Institute of Technology describe some of the policy implications of the new findings. Among them:
- Because black carbon particles have relatively short atmospheric lifetimes, successful control efforts could curb their effects in a matter of months or years. Carbon dioxide remains in the atmosphere for hundreds of years, meaning control efforts couldn't impact global warming for generations.
- Soot emissions come primarily from developing nations such as India and China. If these emissions do in fact play a large role in global warming, that could shift pressure for environmental control to those nations. Industrialized nations in North America and Europe are responsible for the bulk of carbon dioxide emissions.
- Efforts to control soot may also bring immediate improvements in human health since the small particles thought to be most active in affecting climate are the same PM 2.5 particles that cause respiratory distress when trapped deep in the lungs.
- Little is known about the worldwide impact of soot emissions or even how to properly measure them. Significant new research will be needed before the role of black carbon can be reliably assessed.
"The study reported this week in Science really raises some important policy issues regarding soot," said Michael Bergin, an assistant professor in Georgia Tech's School of Earth and Atmospheric Sciences. "In the past, researchers have felt that soot didn't really have a significant warming effect. But as we've learned more about the amount of black carbon emitted by countries like China and India, it appears now that soot could have important climate affects, and that these effects may be almost as much as those of carbon dioxide."