Eugene S. Takle
© 2005
Recent analysis of the cooling effect of atmospheric particulates by Bellouin et. al (2005) rely on both model and recent satellite measurements to narrow the range of uncertainty on this important contribution to the global energy balance. The cooling due to aerosol particles is widely known to be offsetting part of the increase in global temperatures due to increases in atmospheric greenhouse gas concentrations. Continuing efforts to reduce aerosol emissions from industrial, agricultural and other sources and to reduce emissions of gases such as SO2 that lead to sulfate aerosol formation will reduce part of the aerosol masking of global warming. Coakley (2005) reviews the Bellouin et al (2005) paper and points out that their estimate of 0.8 ± 0.1 Watt/m2 is at the high end of the previous consensus estimates of 0.2 to 1.0 W/m2 (IPCC 2001). This is in contrast to the estimated 2.4 ± 0.2 W/m2 warming due to greenhouse gases. Coakley further points out that the Bellouin et al paper leaves a few remaining uncertainties, however, such as aerosol indirect forcing and biases in the new satellite data that remain to be resolved.
References
Coakley, J., 2005: Reflections on aerosol cooling. Nature 438, 1091-1092.
Bellouin, N., O. Boucher, J. Haywood, and M.S. Reddy, 2005: Global estimate of aerosol direct radiative forcing from satellite measurements. Nature, 438, 1138-1141.