A system of ocean currents that plays a major role in the transport of heat from low to high latitudes and, therefore, in global climates. It is driven by the convective overturning of water near the edge of the northern sea ice, where cold, saline water sinks to the ocean floor and travels south as the North Atlantic Deep Water, eventually to the Southern Ocean, where it joins the Antarctic Circumpolar Current. Part of the current turns north into the Indian Ocean, rising to become an intermediate current flowing about 1000 m below the surface. The current crosses the equator, follows a clockwise path in the N. Pacific, continues westward through the islands of Indonesia, crosses the equator once again, crosses the Indian Ocean, flows around Africa, then northward, crossing the equator for the fourth time and returning to the N. Atlantic and the edge of the northern sea ice. It is sometimes known informally as the Atlantic Conveyor.