North Atlantic ‘Cold Blob’ Linked to Weakening AMOC

Scientists have identified a large, persistently cooling area of water in the North Atlantic, south of Greenland and Iceland, known as the “cold blob.” The region has cooled by about 1 °C since 1900, and the cooling extends more than 1,000 m deep. A new study coordinated by Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research attributes the phenomenon to a weakening of the Atlantic Meridional Overturning Circulation (AMOC), the oceanic “conveyor belt” that transports tropical heat northward. The researchers state, “It is changing ocean heat transport,” and note that the AMOC’s slowdown may be driven by fresh‑water influx from melting ice. If the AMOC approaches a tipping point, potential impacts include accelerated sea‑level rise along the U.S. East Coast, harsher winters in Europe, and altered African monsoon patterns that could cause prolonged droughts. The study adds to mounting evidence that the AMOC is at its weakest in roughly a millennium, but scientists caution that data remain sparse and conclusions are provisional.