Propelled by the Sinking of Cold, Salty waters

The Great Ocean Conveyor is propelled by the sinking of cold, salty (and therefore denser) waters in the North Atlantic Ocean (blue arrows). That creates a void that pulls warm, salty Gulf Stream waters northward (red arrows). The Gulf Stream gives up its heat to the atmosphere above the North Atlantic Ocean, and prevailing winds (large red arrows) carry the heat eastward to warm Europe.