North Atlantic “Cold Blob” Linked to Weakening Ocean Circulation

Scientists have identified a persistent region of cooling in the sub‑polar North Atlantic, south of Greenland and Iceland, known as the “cold blob” or North Atlantic warming hole. A study published in *Geophysical Research Letters* analyzed ocean heat content and surface flux data and concluded that the cooling is driven primarily by a reduction in heat transport by the Atlantic Meridional Overturning Circulation (AMOC), rather than by increased heat loss to the atmosphere. The researchers found that the decline in ocean heat content extends down to roughly the upper 1,000 m, the depth associated with northward heat transport by the AMOC.

The weakening of the AMOC could diminish the warm water that moderates Europe’s climate, potentially leading to harsher winters and hotter, more extreme summers on the continent. The authors warn that “this risk demands urgent attention from policymakers.” Seasonal forecast guidance also notes that a strengthening El Niño expected later in 2026, combined with the Atlantic cold anomaly, may alter jet‑stream patterns and affect storm tracks across North America and Europe during the early winter of 2026‑27.

The findings underscore a possible link between the cold blob and broader climate impacts, prompting calls for closer monitoring of Atlantic circulation and its role in regional weather extremes.