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 1%/year CO2 increase experiment (to quadrupling). These datasets are available in netCDF and GRIB format. This simulation was initiated from year 0400 of CCSM3 model run b30.009 and executed on hardware Earth Simulator Center, JAMSTEC. The input external forcings are ozone forcing : pcmdio3.r8.64x1_L60_clim_c970515.nc aerosol optics : AerosolOptics_c040105.nc aerosol MMR : AerosolMass_V_128x256_clim_c031022.nc carbon scaling : none solar forcing : constant GHGs : none GHG loss rates : none volcanic forcing : none DMS emissions : none oxidants : none SOx emissions : none 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. For this experiment there is only one run available. Model output data for CMIP3 in higher temporal resolutions and further variables are available in ESGF at https://esgf-node.llnl.gov/search/cmip3/.