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Study reveals urban smoke absorbs sunlight, exacerbating climate warming
Cloaking urban areas and wildfire zones, tiny smoke particles suspended in the atmosphere have a sizeable effect on our climate. First field demonstration of warming caused by soot and brown carbon
LOS ALAMOS, N.M., Sept. 30, 2015?Cloaking urban areas and wildfire zones, tiny smoke particles suspended in the atmosphere have a sizeable effect on our climate. But the exact effect of many of these aerosols?such as how much sunlight they absorb, thus warming Earth, or reflecting back to space and so cooling Earth?is very uncertain.
?The new measurements resolve carbon particles that are of several types, each with its own effect on climate,? said project leader Manvendra Dubey of Los Alamos National Laboratory.
?Black carbon, from both city-related biomass combustion, is the most sunlight absorbing. Brown carbon, from sources such as residential wood combustion and forest fires, is the component that is missing in most climate models and can be a significant absorber of sunlight, making it as bad for climate warming as black carbon,? Dubey said.
?In fact,? he noted, ?brown carbon is erroneously treated as organic carbon in climate models that show it scattering sunlight to exert a cooling effect. Recognizing brown carbon's heating effects will require significant adjustment to current climate models. Furthermore, we have determined that organic carbon coatings amplify black carbon?s light absorbing power by focusing sunlight, which exacerbates their warming effect.?
The new evidence appears in a paper published today by Nature Communications. Notably, the analysis reveals that climate models could be minimizing smoke?s warming effect because the models did not factor in the regionally specific features that determine the light-absorbing carbon particle?s outer coatings and its composition, both of which control how strongly particles absorb sunlight....
Cloaking urban areas and wildfire zones, tiny smoke particles suspended in the atmosphere have a sizeable effect on our climate. First field demonstration of warming caused by soot and brown carbon
LOS ALAMOS, N.M., Sept. 30, 2015?Cloaking urban areas and wildfire zones, tiny smoke particles suspended in the atmosphere have a sizeable effect on our climate. But the exact effect of many of these aerosols?such as how much sunlight they absorb, thus warming Earth, or reflecting back to space and so cooling Earth?is very uncertain.
?The new measurements resolve carbon particles that are of several types, each with its own effect on climate,? said project leader Manvendra Dubey of Los Alamos National Laboratory.
?Black carbon, from both city-related biomass combustion, is the most sunlight absorbing. Brown carbon, from sources such as residential wood combustion and forest fires, is the component that is missing in most climate models and can be a significant absorber of sunlight, making it as bad for climate warming as black carbon,? Dubey said.
?In fact,? he noted, ?brown carbon is erroneously treated as organic carbon in climate models that show it scattering sunlight to exert a cooling effect. Recognizing brown carbon's heating effects will require significant adjustment to current climate models. Furthermore, we have determined that organic carbon coatings amplify black carbon?s light absorbing power by focusing sunlight, which exacerbates their warming effect.?
The new evidence appears in a paper published today by Nature Communications. Notably, the analysis reveals that climate models could be minimizing smoke?s warming effect because the models did not factor in the regionally specific features that determine the light-absorbing carbon particle?s outer coatings and its composition, both of which control how strongly particles absorb sunlight....