Brown Carbon Plays Larger Role In Climate Than Assumed, Study Says

Climate models are underestimating the effects of so-called brown carbon from sources such as forest fires because the models do not account for regional factors — such as areas where wood-burning stoves are common — when estimating brown carbon’s climate-warming impacts. Black carbon, primarily from urban combustion sources like vehicles and factories, absorbs the most sunlight, the researchers explain, and it’s well-accounted for in climate models. However, most models don’t properly account for brown carbon, the researchers say. Brown carbon “can be a significant absorber of sunlight, making it as bad for climate warming as black carbon,” said co-author Manvendra Dubey of Los Alamos National Laboratory. The study, published this week in Nature Communications, stresses the differing effects of black and brown carbon on the climate: Solid wood combustion, a source of brown carbon soot, is pervasive during United Kingdom winters, but very uncommon in other study locations, such as Los Angeles, which generally sees more black carbon soot from vehicles.