Aerosols alter warming less than thought
By analysing existing models and combining the results with his own observations, Gunnar Myhre of the Center for International Climate and Environmental Research in Norway found that estimates of light-reflecting airborne particles had underestimated the build-up of soot, which actually absorbs heat, reducing the overall cooling effect of the reflective particles.
Once soot and other smaller factors have been considered, reflective airborne particles are still believed to dim sunlight by about 0.3 watts per square metre (a UN team of scientists put that figure at 0.5 watts in 2007), which offsets a tenth of the heat-trapping impact of greenhouse gases.
Myhre and colleagues from the Met Office are investigating whether sunlight-reflecting particles, which include sulphates and nitrates, could be safely used to deliberately mask global warming in the future.
August 2009
Once soot and other smaller factors have been considered, reflective airborne particles are still believed to dim sunlight by about 0.3 watts per square metre (a UN team of scientists put that figure at 0.5 watts in 2007), which offsets a tenth of the heat-trapping impact of greenhouse gases.
Myhre and colleagues from the Met Office are investigating whether sunlight-reflecting particles, which include sulphates and nitrates, could be safely used to deliberately mask global warming in the future.
August 2009
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