The North Atlantic drift is a powerful warm ocean current that continues the Gulf Stream northeast. It splits in two west of the British Isles. One branch (the Canary current) goes south while the other continues north along the coast of northwestern Europe where it has a considerable warming influence on the climate.

If this current is sufficiently disrupted it could cause the mean temperature for Western Europe fall by 5° Celsius. Recent studies have provided some evidence of the current slowing. It is thought this may be caused by global warming leading to increased rainfall and melting of the Arctic pack ice. As the current is powered both by water temperature and salinity in the North Atlantic, such an increase of fresh water may pose a risk of disruption.