Atlantic ‘Cold Blob’ Signals Weakening of AMOC

A research team led by Prof. Stefan Rahmstorf at the Potsdam Institute for Climate Impact Research has published a study in *Geophysical Research Letters* describing a persistent “Cold Blob” – a cooling patch in the North Atlantic south of Greenland where temperatures have fallen about 1 °C since the 19th century. The analysis links the cooling to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), which transports warm water northward and cold water southward, reducing lateral heat transport to the sub‑polar gyre.

The scientists warn that further weakening of the AMOC could have severe climate impacts, including colder winters in northern Europe, rising sea levels along the US east coast, and intensified Atlantic storms. They cite “early‑warning signals” that the circulation may be approaching a tipping point and call for urgent political attention. The study also references a recent Nordic Council warning that winter temperatures in Iceland could drop to –45 °C, a scenario not seen since Viking times.