The value of CO2 increases gradually from the initial value (approximately equal to the value observed in 1958). The rate of 1% per year increase in CO2 is approximately equal to the rate of total radiative forcing of all greenhouse gases (CO2 +O3 + freons + ..) of the IPCC "business as usual" scenario. The initial conditions in the model atmosphere and ocean are in no way related to the conditions in 1958. Therefore due to natural variability both in the model and in the observed climate the state is different even though the radiative forcing was about equal between model and nature. These data represent monthly averaged surface values of selected variables for the IPCC-Data Distribution Centre. (see also http://www.ipcc-data.org/ )