The atmosphere-ocean general circulation model ECHAM3/LSG is used for climate change and climate variability studies. Up to 1985 the concentration followswere taken from observation (Schoenwiese et al., 1990) and for the following years the IPCC scenario A (Business as Usual, Houghton et al., 1990) was applied. In addition the direct effect of suphate aerosols was simulated. The aerosol data were calculated using the MOGUNTIA sulphur model (Lange and Rhode, 1991). The Sulphate emissions were taken from historical data and from projected future emissions from the IPCC 1992 scenario A. The models ECHAM3 and LSG are described in the DKRZ reports No.6 and No.2, respectively. These data represent monthly averaged surface values of selected variables for the IPCC-Data Distribution Centre. (see also http://www.ipcc-data.org/ )