The AMOC consists of an upper cell and a deep sea or abyssal cell that sits underneath. The upper cell transports warm water from the subtropical South Atlantic Ocean across the equator northward toward high latitudes in the North Atlantic, where it cools, sinks, and flows equatorward as cold deep water. It sits atop a cell of colder, denser water at the ice edge of Antarctica known as the abyssal cell. These waters flow north along the seafloor into the North Atlantic where they slowly rise and mix with other waters that flow back to the south. Together, these cells carry a maximum of 25% of the net global ocean and atmosphere energy (heat) transport.