MODEL-CALCULATIONS OF COMPETING CLIMATIC EFFECTS OF SO2 AND CO2 IN FOSSIL-FUEL COMBUSTION

Fossil fuel combustion has two competing effects on the climate system , a warming due to the emission of CO2 and other trace gases and a coo ling due to sulphate particles formed from the SO2 emission. A detaile d parameterization of the relationship between fossil fuel burning and the SO2 effect on backscattering and cloud albedo is implemented in a one-dimensional radiative-convective model for assessing the climatic impact. The results show that at present the cooling induced by the c ombined effect of SO2 completely counteracts the CO2 greenhouse warmin g. The model predicts that by the year 2060 the SO2-induced cooling re duces warming due to CO2 by 66% in the IPCC scenario Ball and by 27% i n the IPCC scenario D. Attempts to slow-pace the fossil fuel burning w ill decrease the SO2 concentration, which could further increase globa l warming.