Why do some ocean currents carry warm water far from the tropics?

Large ocean currents are driven mainly by global winds, the Coriolis effect from Earth’s rotation, and the arrangement of continents. Warm water tends to move poleward in currents such as the Gulf Stream and its extension into the North Atlantic, transporting heat far from the tropics. That redistribution of heat is one reason western Europe is milder than other places at similar latitudes. Currents also influence storms, marine ecosystems, and nutrient cycling. Because the ocean stores and moves vast amounts of heat, current shifts can have major climate effects.