Atmospheric aerosols can directly affect Earth’s energy balance by reflecting incoming solar radiation (a cooling effect), absorbing incoming radiation (a warming effect), and emitting infrared. The net overall effect depends most strongly on whether the aerosols absorb or reflect solar radiation. Black carbon is an example of a strongly absorbing aerosol that is also an important global warming agent; one-third of the global black carbon budget is due to biomass burning. Climate models typically treat black carbon as the only organic absorbing aerosol, but in reality other organic aerosols can absorb solar radiation, although typically not as strongly as black carbon. These partly absorbing aerosols are often referred to as brown carbon.
Brown carbon has not been treated in detail in climate models because its absorption properties and composition are highly variable. In collaboration with scientists at Carnegie Mellon University and the University of Montana, an Atmospheric System Research-funded team of scientists at Los Alamos National Laboratory recently made discoveries that will make it easier for climate modelers to more accurately represent both black and brown carbon emissions from biomass burning as part of the simulations. They conducted a set of laboratory experiments that quantified the absorption properties of emissions from a range of common biomass fuels as well as diesel. They showed that the absorption properties of brown carbon from biomass burning depends more on burn conditions than fuel type and that compounds with extremely low volatility are responsible for the absorption. These results should enable climate models to treat both black and brown carbon and quantify how fires contribute to warming now and in the future.
Reference: Saleh, R., E. S. Robinson, D. S. Tkacik, A. T. Ahern, S. Liu, A. C. Aiken, R. C. Sullivan, A. A. Presto, M. K. Dubey, R. J., Yokelson, N. M. Donahue, and A. L. Robinson. 2014. “Brownness of Organics in Aerosols from Biomass Burning Linked to Their Black Carbon Content,” Nature Geoscience 7, 647-50. DOI: 10.1038/ngeo2220. (Reference link)
Contact: Shaima Nasiri, SC-23.1, 301-903-0207
SC-33.1 Earth and Environmental Sciences Division, BER
BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER
Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]
Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]
Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]
Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.
Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco
List all highlights (possible long download time)