So much for global warming being settled and the infallibility of incomplete and inadequate climate models.
Climate models generally take the effect of wildfires (brown carbon) on climate to be zero (it is not a parameter that is normally included). Both black and brown carbon particulates are products of incomplete combustion.
A new paper reports on experiments with the combustion of biomass and the brown carbon particulate matter in the smoke:
Saleh et al, Brownness of organics in aerosols from biomass burning linked to their black carbon content. Nature Geoscience (2014) doi:10.1038/ngeo2220
The research provides information which can now be included in climate models but since it is a parameter which is not usually included, the obvious conclusion is that for any given level of warming some other effect (most likely that of man-made emissions of carbon dioxide) has been overestimated in the models.
But it is not the obvious conclusion that makes the headlines. Instead it is the ridiculous and alarmist statement that “Forest fires can heat the climate“ that is the headline that Swedish Radio (which is about as orthodox as they come) chooses to lead with. They would clearly like to project the picture of a greater threat and not that of inadequate climate models.
Abstract: …. Here we present smog chamber experiments to characterize the effective absorptivity of organic aerosol from biomass burning under a range of conditions. We show that brown carbon in emissions from biomass burning is associated mostly with organic compounds of extremely low volatility. In addition, we find that the effective absorptivity of organic aerosol in biomass burning emissions can be parameterized as a function of the ratio of black carbon to organic aerosol, indicating that aerosol absorptivity depends largely on burn conditions, not fuel type. We conclude that brown carbon from biomass burning can be an important factor in aerosol radiative forcing.
The paper claims that brown carbon is a significant factor which must be taken into account and the more significant it is the less significant is man-made carbon dioxide.
Tags: brown carbon, global warming, man-made carbon dioxide emissions, Particulates, warming effects, Wildfires
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