Weakening of Atlantic Meridional Overturning Circulation (AMOC): Implications for Indian Monsoon and Global Climate

The Atlantic Meridional Overturning Circulation (AMOC) is a complex system of ocean currents that acts as a global conveyor belt, transporting warm surface water from the tropics toward the North Atlantic and returning cold, salty water at depth. Recent oceanographic evidence published in 'Nature Climate Change' suggests that this critical system is weakening at an alarming rate, nearing a potential tipping point. This slowing is primarily attributed to the influx of freshwater from melting Arctic ice and increased precipitation, which reduces the density of surface waters and inhibits the sinking process necessary for the circulation. For the Indian subcontinent, the weakening of the AMOC is not merely a distant geographical phenomenon but a direct threat to the Indian Summer Monsoon (ISM). The AMOC plays a pivotal role in maintaining the thermal gradient between the Northern and Southern Hemispheres. As the AMOC slows, the North Atlantic cools, causing a southward shift of the Intertropical Convergence Zone (ITCZ)—the tropical rain belt. Such a shift is historically linked to decreased monsoon rainfall over India and increased variability in precipitation patterns.