Overview
- New peer-reviewed work in Science Advances projects the Atlantic overturning circulation will weaken by roughly 51% to 59% this century after researchers recalibrated models with real-world ocean data.
- Scientists found many models made the South Atlantic too fresh and the North Atlantic too cold, so they used ridge-regularized regression to correct those errors and raised the projected slowdown while tightening the range.
- Observations from moored sensors show the current has already declined by about 10% to 20% since the mid-2000s, and a 2025 U.S. study tied the recent weak phase to as much as half of Northeast coastal flooding since 2005.
- A weaker circulation would shift heat and rain belts, with studies warning of a weaker Indian summer monsoon and more erratic El Niño events that can swing South Asia between drought and destructive floods.
- Researchers say deep emissions cuts could limit the weakening to about 20%, and a separate Science Advances study on ancient volcanic clusters shows the system can change quickly, highlighting its sensitivity to climate shocks.