North Atlantic Cold Blob Linked to Intensified European Heatwaves

Scientists have identified a persistent region of unusually cold water in the North Atlantic, known as the “cold blob,” that is defying the overall warming of the oceans. Studies attribute the anomaly to increased freshwater from melting Greenland ice, which reduces surface salinity and hampers the Atlantic Meridional Overturning Circulation (AMOC). The weakened circulation creates a sharp temperature contrast that disrupts the jet stream, causing it to meander and stall, which can trap hot air over Europe and produce prolonged heat domes.

Researchers say the cold blob can paradoxically exacerbate heat extremes. Oceanographer Gerard McCarthy noted, “A cold Atlantic doesn’t necessarily mean a colder Europe…some of the hot extremes can actually be exacerbated by this cold blob.” Climate physicist Marilena Oltmanns added that the cold anomaly “acts like a guide” for the winds, steering the jet stream northward and fostering heat domes. The phenomenon also raises concerns that a further slowdown of the AMOC could lead to harsher winters in northern Europe in the future.