Climate scientists have identified a cooling patch in the North Atlantic that suggests the Atlantic Meridional Overturning Circulation is weakening.

This phenomenon, known as the "cold blob" or "warming hole," represents a significant shift in how heat is distributed across the planet. Because the Atlantic Meridional Overturning Circulation, or AMOC, acts as a conveyor belt moving warm water from the tropics to the north, any slowdown threatens to disrupt global weather patterns.

The cooling patch is located southeast of Greenland and extends south of Iceland [1, 2]. According to data reported in June 2026, this specific region of the ocean has cooled by up to 1 degree Celsius [1]. Researchers said that this cooling trend has been observed over a period of approximately 150 years [1].

Scientists said the temperature drop is due to a reduction in the transport of warm water northward [1, 2]. While previous reports indicated that researchers were split over the cause of the anomaly, more recent evidence supports the theory that the weakening AMOC is the primary driver [2].

The discovery highlights the sensitivity of ocean currents to changing environmental conditions. The AMOC is critical for regulating temperatures in the Northern Hemisphere, and a persistent cooling trend in the North Atlantic serves as a physical marker of a slowing system [1, 2].

“The 'cold blob' is interpreted as a sign that the AMOC is weakening”

The weakening of the AMOC does not necessarily imply a sudden global cooling event, but it indicates a fundamental change in ocean dynamics. As the transport of heat from the equator to the poles slows, it can lead to regional temperature anomalies and potentially alter precipitation patterns, affecting agriculture and sea levels in the North Atlantic region.