North Atlantic cold patch and ancient Gulf Stream shift warn of AMOC weakening

Scientists have identified a vast region of unusually cold water in the North Atlantic south of Greenland and Iceland, termed the “cold blob”. Recent research links this anomaly to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), as freshwater from melting ice reduces the ocean’s ability to sink and drive the conveyor‑belt‑like current. If the trend continues, models predict higher sea levels along parts of North America, altered rainfall patterns, stronger droughts in Europe and Africa, and broader climate disruptions.

Paleo‑oceanographic analysis of seabed sediments off Nova Scotia reveals that during the Younger Dryas, a rapid 13,000‑year‑old cooling event, the Gulf Stream shifted hundreds of kilometres northward, warming Atlantic Canada by up to 5 °C while Europe and Greenland chilled. This ancient response mirrors model projections for a weakened AMOC today, providing direct geological evidence that such circulation changes can occur abruptly and have far‑reaching climatic effects.