Wildfire dark brown carbon rivals soot as a major driver of global warming, new study finds

A new study published in Nature Geoscience reveals that dark brown carbon from wildfires absorbs sunlight far more strongly than previously thought, rivaling black carbon (soot) as a contributor to global temperature rise. Researchers analyzed smoke plumes from fires across five continents and found that this brown haze can absorb visible light five to 15 times more intensely than older models assumed. In some cases, its warming effect matched or even exceeded that of black carbon. The study, led by Lulu Xu at the Chinese Academy of Sciences, used aircraft, ground stations, and satellite data to track the particles globally. The warming impact was not limited to fire regions; it extended into the Arctic, where dark particles on snow and ice accelerate melting. This means climate models that treat brown carbon as a weak absorber have been undercounting the heat from wildfires, an oversight that becomes more critical as fire frequency and intensity increase worldwide.