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 1 ensemble runs available. Forcing agents: CO2,CH4,N2O,CFC11(including other CFCs and HFCs), CFC12 and sulfate aerosols (Boucher data, only direct effect) kept at year level. Non-varying forcing agents: Background aerosols: black carbon, sea salt, desert dust, stratospheric and tropospheric ozone, solar irradiance (1368 W/m2) and the distribution of land cover types. No volcanic aerosols. No heat or fresh water adjustments. Model output data for CMIP3 in higher temporal resolutions and further variables are available in ESGF at https://esgf-node.llnl.gov/search/cmip3/.