Results from simulations with the coarse-resolution version of MPI-ESM performed by the RETRO team at DKRZ. The left side shows a normal (prograde) rotating earth. The right side shows a backwards (retrograde) rotating earth. The simulations are forced with pre-industrial boundary conditions. For the full description see the Earth System Dynamics manuscript "The climate of a retrograde rotating earth". In the retrograde simulation (right), much more sea ice is formed in the North Atlantic and the Nordic Seas. This is related to a shift of the deep water formation into the Pacific and drastically reduced ocean heat transports in the North Atlantic. The west coast of the Antarctic Peninsula sees a drastic increase in sea ice.