Scientists are increasingly alarmed about the stability of a vast system of ocean currents in the Atlantic, after new research suggested it could weaken far more severely than previously thought. The Atlantic Meridional Overturning Circulation (AMOC), which regulates climate across much of the globe, may slow by up to 59% by 2100, with potentially devastating consequences for weather systems as far away as the Indian subcontinent.The findings have particular significance for India, where hundreds of millions of people depend on the summer monsoon for their agricultural livelihoods and water supplies. Here is what to know.Think of the Earth’s oceans as having a massive, invisible conveyor belt. In the Atlantic Ocean, this system is scientifically known as the Atlantic Meridional Overturning Circulation.Warm, salty surface water from the tropics flows north towards Greenland. As it reaches the freezing Arctic, the water cools, becomes denser, and sinks several kilometres into the deep ocean. It then drifts back south as a cold deep-water current before eventually rising to the surface to warm up and restart the loop.This slow machinery moves vast amounts of heat across the globe. To put its pace in perspective, a single cubic metre of water takes about 1,000 years to complete the journey. It is the reason Europe has a mild climate, and it heavily influences rainfall in Africa, the Americas, and Asia.Why are scientists warning of a “tipping point”?The conveyor belt relies on a delicate balance of ocean temperature and salt levels. However, human-induced climate change is melting Arctic ice at an alarming rate, dumping massive amounts of fresh water into the North Atlantic. Because fresh water is lighter and less salty, it does not sink easily. This is acting like a brake on the entire AMOC system.While past studies estimated a 15% slowdown over the last 50 years, new research using real-time ocean measurements projects a much sharper decline, potentially weakening the currents by up to 59% by 2100.Story continues below this adAlso in Explained | Collapse of critical Atlantic current is no longer low-likelihood: What a new study saysThis matters because the AMOC is a “climate tipping point.” Just like a chair tilted past its balancing point – once the AMOC crosses a certain threshold, it could irreversibly collapse into a new, sluggish state. Scientists debate the exact timeline, though some warn it could happen as early as this century. If it does, the consequences would be catastrophic, triggering extreme sea-level rise in North America and severe weather disruptions globally.The El Niño ConnectionThough the AMOC is in the Atlantic, its breakdown would trigger chaos in the Pacific.El Niño is a periodic warming of the Pacific Ocean that disrupts global weather. Because global ocean currents and wind patterns are deeply interconnected, a sluggish AMOC traps heat in the southern hemisphere and leaves the North Pacific cooler.This throws off the delicate temperature balance that drives El Niño. Studies suggest a weaker AMOC will make El Niño events more unpredictable and extreme. For context, recent powerful El Niños (like those in 2015-16 and 2023-24) caused massive worldwide disruptions, triggering droughts in the Americas and suppressing rainfall over South Asia.Why does this matter for India?Story continues below this adFor India, an AMOC collapse is more than a distant oceanic event, as it is a direct threat to food security. The Indian summer monsoon, which is the backbone of the country’s agriculture and economy, relies on specific global heat distributions. When the Atlantic conveyor slows down, less heat travels north. This shift pulls the planet’s tropical rain belt southward, away from the Indian subcontinent.NewsletterFollow our daily newsletter so you never miss anything important. On Wednesday, we answer readers' questions.SubscribeResearch indicates this would severely weaken the wind systems that carry moisture from the Arabian Sea into India. The result would be shorter wet seasons, longer dry spells, and an overall drying trend. Furthermore, an unpredictable El Niño, worsened by the AMOC’s decline, would only compound these climate risks, trapping Indian farmers between extreme droughts and erratic, destructive floods.