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 committed climate change experiment (COMMIT). These datasets are available in netCDF and GRIB format. For this experiment there are 5 ensemble runs available. This simulation was initiated from year 2000 of CCSM3 model run b30.030a and executed on hardware bluesky.ucar.edu. The input external forcings are ozone forcing : mozart.o3.128x64_L18_2000_c040526.nc aerosol optics : AerosolOptics_c040105.nc aerosol MMR : AerosolMass_V_128x256_clim_c031022.nc carbon scaling : carbonscaling_1870-2000_c040225.nc solar forcing : Fixed at 1366.5 W m-2 GHGs : ghg_1870_2100_c040122.nc GHG loss rates : noaamisc.r8.nc volcanic forcing : none DMS emissions : DMS_emissions_128x256_clim_c040122.nc oxidants : oxid_128x256_L26_clim_c040112.nc SOx emissions : SOx_emissions_128x256_L2_1850-2000_c040321.nc Physical constants used for derived data: Lv (latent heat of evaporation): 2.501e6 J kg-1 Lf (latent heat of fusion ): 3.337e5 J kg-1 r[h2o] (density of water ): 1000 kg m-3 g2kg (grams to kilograms ): 1000 g kg-1 Integrations were performed by NCAR and CRIEPI with support and facilities provided by NSF, DOE, MEXT and ESC/JAMSTEC. Model output data for CMIP3 in higher temporal resolutions and further variables are available in ESGF at https://esgf-node.llnl.gov/search/cmip3/.