The Meridional Overturning Circulation (MOC) is a system of ocean currents that primarily moves water in a north-south direction across the globe. In the Atlantic Ocean, this system is known as the Atlantic Meridional Overturning Circulation (AMOC). Warm, salty surface water flows northward from the tropics toward the North Atlantic, where it cools, becomes denser, and sinks to form deep water, such as the North Atlantic Deep Water (NADW). This deep water then flows southward toward the Southern Ocean and eventually circulates into the Indian and Pacific Oceans, completing a global loop.
Recent studies indicate that the AMOC has been gradually weakening over the past decades, with observational data showing a decline of about 15% since the mid-20th century, likely due to freshwater input from melting Greenland ice and climate variability.
