This is the 4000-yr control run with MPI-ESM-CR v. 1.2, carried out with fixed preindustrial CO2 concentrations. It provides the initial conditions for the abrupt 2% CO2 increase forcing and 1% ramp-up ensembles in the same project. Initial conditions are distance by 200 years in order to ensure reasonable decorrelation. The experiment is performed with MPI-ESM model, coarse resolution (CR: T31). The project is aimed as a testbed for the Green’s functions computed via the 2xCO2abrupt experiment. This is a model application of the linear response theory, as described in Lembo et al. 2020 (see references).