The North Atlantic thermohaline circulation transports a large amount of heat northwards, and is partly responsible for the mild climate of Western Europe. Projections of this circulation over the 21st century using the Community Climate System Model will be shown. The thermohaline circulation slows down at a rate which is proportional to the rate of increase of greenhouse gases over the 21st century. Despite this slowdown, the climate of Western Europe is projected to warm into the future. The unknown factor that could change this scenario is the rate at which the Greenland ice sheet will melt over the next century. This could further reduce the strength of the North Atlantic thermohaline circulation, as well as significantly contribute to the future rise in the global sea level.