The Atlantic Meridional Overturning Circulation (AMOC) transports warm surface water northward across the equator, carrying heat from the Southern to the Northern Hemisphere. AMOC plays a central role in the global redistribution of heat and precipitation during both abrupt and longerterm climate shifts. Over the next century, AMOC is projected to weaken due to greenhouse gas warming, though the skill of these projections is dependent on a better understanding of how AMOC changes are forced, including the evolving states of its constituent water masses.