The coupling of models of different subsystems of the Earth forms a necessary steptowards a dynamic Earth system model which is physically consistent with respect to Earth rotation,gravity and surface deformation. In a cooperative project with contributions from meteorology, oceanog-raphy, hydrology and geodesy the fluxes of momentum, energy and mass between atmosphere, ocean,continental hydrosphere and rigid Earth have been jointly simulated for centennial periods. The corre-sponding variations of the Earth’s rotation, gravity and shape have been calculated and compared withsatellite data. This paper and the following four ones are closely linked.