In recent years, a new round of climate simulations with improved coupled models has been performed. Experiments include simulations of the 20th century with realistic external forcing (solar radiation, sulfate aerosols) and different scenario calculations for the 21st century. This presentations will try to assess the 20th century performance of climate models in high northern latitudes. Ocean-sea ice hindcast simulations will be utilized in this assessment. Some fundamental problems in ocean-sea ice hindcasts will be addressed. The presentation concludes with examples of possible changes in the Arctic fresh water reservoirs over the 21th century according to the A1B scenario.