These data represent monthly mean values of selected variables for ENSEMBLES (http://www.ensembles-eu.org). The list of output variables can be found in: http://ensembles.wdc-climate.de/output-variables. The model output was prepared for the ENSEMBLES Stream 2 experiment and comprises the HadCM3C run aebag (1/12/1999-1/01/2100). The model was initialised from the HadCM3C 20C3M run 1 using 1999 conditions. Although the model contains an interactive land/ocean carbon cycle, anthropogenic forcings (only) were prescribed to follow A1B scenario concentration values (according to the IMAGE2.2 model, not the IPCC marker) rather than emissions, i.e. prescribed changes in concentrations of: CO2, CH4, N2O, CFC11*, CFC12, Ozone. (In this experiment CFC11* or equivalent-CFC11 is used to represent other halocarbon gases apart from CFC12). Sulphur-cycle emissions also provide a forcing input. No variations were made to solar radiation and volcanic aerosols. Some model-specific and scenario-specific forcings were needed for this experiment, in particular ship track emissions of sulphate aerosol precursors. For composition of dataset names see experiment METO-HC_HADCM3C_20C3M_1. For this experiment 1 run was carried out (data relating to aerosol variables and carbon cycle variables is included).