Changes in the Gulf Stream, a strong ocean current in the Atlantic, could serve as an early warning of the imminent collapse of the Atlantic Meridional Overturning Circulation (AMOC). The AMOC is a massive system of ocean currents that acts as a conveyor belt, moving heat from the tropics to the North Atlantic. The part of this system that flows along the east coast of the United States and then east toward Europe is the Gulf Stream. Scientists are concerned that if the AMOC were to collapse, it could trigger drastic climate shifts, especially in Europe, where temperatures could plummet.