North Atlantic cold blob signals weakening of key ocean current

Scientists have identified a persistent patch of unusually cool water south of Greenland, dubbed the "cold blob" or "warming hole," in the North Atlantic. Reanalysis of ocean temperature, salinity and current data links the anomaly to a significant weakening of the Atlantic Meridional Overturning Circulation (AMOC), a major component of the global ocean conveyor belt that regulates climate in Europe and North America.

Research published in Geophysical Research Letters and highlighted by outlets such as Phys.org and the IPCC’s Sixth Assessment Report suggests the AMOC may be approaching a critical tipping point. A slower AMOC could intensify winter storms in Europe, raise sea levels along the U.S. East Coast, and alter rainfall and storm tracks across the Atlantic basin. While a full collapse is not deemed imminent, the cold blob provides growing evidence that the system is already weakening.

Monitoring efforts by NOAA and international partners continue, emphasizing the need for enhanced observations and greenhouse‑gas mitigation to limit further slowdown and its potential climate impacts.