The data represent the fully forced experiment for the MPI-M Millennium Project ( http://www.mpimet.mpg.de/en/wissenschaft/working-groups/millennium.html ) using the comprehensive MPI-M Earth System Model ECHAM5/JSBACH/MPI-OM/HAMOCC including the biogeophysical and biogeochemical effects of an interactive carbon cycle. This experiment is the second millennium simulation including the complete set of recent reconstructions of time-dependent climate forcing components and corresponds to the mil0001 control experiment (see http://cera-www.dkrz.de/WDCC/ui/Entry.jsp?acronym=mil0001) The model is run for the years 800 to 2000 under the following time-dependent forcing components: (1) optical properties of stratospheric sulphate aerosols from volcanic eruptions (T. Crowley), (2) variation of total solar irradiance (N.Krivova, 2008), (3) exact calculation of changes in the parameters of the earth's orbit, (4) land use change (J. Pongratz). Technical details: The experiment used the following models/resolutions: ECHAM5 (EH5) Version 5.4.01 at T31L19 resolution JSBACH (JSB) at T31 resolution, one soil layer, 13 vegetation types and four vegetation tiles per grid box MPI-OM/HAMOCC Version 1.3.0 at GR3.0L40 resolution The output from the experiment is archived at hpss:/dxul/ut/9/prj/im0387/m212098/cosmos-1.1.0_millennium/experiments/mil0012