Atlantic “cold blob” linked to weakening AMOC circulation

A new study of the North Atlantic has identified a large “cold blob” of water extending from the southern edge of Greenland to the vicinity of Iceland. Since 1900 the area has cooled by roughly 1 °C, while surrounding ocean waters continue to warm. Researchers conclude the cooling is a surface‑level manifestation of a weakening Atlantic Meridional Overturning Circulation (AMOC), the oceanic conveyor belt that carries warm tropical water northward. “It is changing the heat transport in the ocean,” said Stefan Rahmstorf, a co‑author of the paper.

The analysis combined satellite‑derived sea‑surface‑temperature data with in‑situ measurements and climate‑model outputs. The authors warn that a further decline in AMOC could trigger rapid sea‑level rise along the U.S. east coast, harsher winters in Europe and disrupted African monsoon patterns that may cause prolonged droughts. While the findings reinforce earlier concerns about AMOC vulnerability, the scientists caution that data gaps remain and the results should be regarded as a robust indication—not a definitive forecast. Commentators such as René van Westen, David Thornalley and Jonathan Baker highlighted the study’s contribution to the growing body of evidence that the Atlantic’s heat‑transport system is under stress from global warming.