Scientists turn their Attention to Black Carbon
Industrial and Biomass black carbon emissions across the globe.
A new study published in the March 24th issue of the Journal Nature Geoscience says that black carbon, a type of aerosol, may be the second most important contributor to climate change after carbon dioxide (CO2) and a key to preventing warming in the short run, as reported by the article in LiveScience.
Black carbon is produced in diesel exhaust and when wood and coal are burned.
Dr. V. Ramanathan of the Scripps Institution of Oceanography in California and lead author of the study says that soot particles absorb and scatter the sun's radiation. Black carbon is the absorbing component of soot.
Using data from satellites, aircraft and surface instruments they estimated that black carbon has a bigger warming effect than earlier though and much more so than what the IPCC estimated in their report.
Dr. Ramanathan suggests that tackling black carbon emissions might be an effective way to prevent some short term climate warming, while figuring out ways to control rising CO2 emissions can still be sorted out.
The researchers found a significant warming effect from black carbon at about 6,500 feet (2 kilometers) altitude, where black carbon absorbs not only sunlight, but the light reflected by clouds at lower altitudes. They say this effect is unaccounted for in model-based estimates used in most studies, meaning that black carbon's actual warming contribution has been underestimated. Its warming impact is more than some greenhouse gases, such as methane, Ramanathan contends in the article.
Atmospheric scientist Dorothy Koch of NASA's Goddard Institute for Space Studies (GISS), who was not affiliated with the study, cautioned that the case wasn't that simple. Black carbon doesn't stay in the atmosphere for long, which means it might have a high effect in the short term, but greenhouse gases that stay in the atmosphere longer have a bigger long-term impact. There is also uncertainty as to just how much of the black carbon in the atmosphere comes from human activities, Koch said.
