North Atlantic Cold Spot Signals Weakening of AMOC

A new study records a persistent cold anomaly—sometimes called a “cold spot” or “warm‑hole deficit”—in the North Atlantic between Greenland and Iceland. Since 1900 the surface temperature of the feature has dropped by nearly 1 °C, and cooling is also observed in deeper layers.

Researchers combined ship, buoy and satellite data with climate‑model simulations and conclude the cooling is tied to a weakening of the Atlantic Meridional Overturning Circulation (AMOC), the oceanic conveyor that transports heat northward. The study cites multiple independent lines of evidence that the AMOC may be at its weakest strength in about a millennium.

Scientists warned that a continued decline could trigger far‑reaching effects: accelerated sea‑level rise along the U.S. East Coast, pronounced winter cooling in north‑western Europe, and shifts in monsoon patterns that could bring prolonged droughts to parts of Africa and Asia. While uncertainties remain, the authors describe the cold spot as an early warning of a possible climate tipping point.