These data represent monthly averaged values of selected variables for the Data Distribution Centre (DDC) of the Intergovernmental Panel on Climate Change (IPCC). (see also http://www.ipcc-data.org/) The model output prepared for IPCC Fourth Assessment SRES B1 experiment. These datasets are available in netCDF and GRIB format. For this experiment there are 5 ensemble runs available. The initial condition is taken from the state of respective year 1990 in the 20C3M run. The forcing of the experiment includes greenhouse gases (CO2, CH4, N2O and CFCs) and sulfate aerosol direct effects, which are based on IPCC SRES-B1 for 1990-2100. This experiment is extended until 2300 with holding the concentrations fixed at 2100 level. For model output data in higher temporal resulution and more variables visit the web page https://esg.llnl.gov:8443/home/publicHomePage.do.