The Gulf Stream, which brings warm water from the Gulf of Mexico to Europe and keeps the climate mild, is only part of a larger system of oceanic currents called the Atlantic Meridional Overturning Circulation, or AMOC for short. It runs through the Atlantic like a giant climate machine: As warm water from the tropics is transported northwards at the surface, the current reverses in the North Atlantic—the water cools, becomes heavier and flows south at depth.
Source:
phys.org