Reanalysis of conditions since 1955 found ocean surface heat loss has decreased, undercutting theories that winds or clouds alone created the cold patch through atmospheric cooling.
Stefan Rahmstorf said only reduced inflow of warm water can explain the deep cooling, arguing the data show the ocean circulation—not the atmosphere—is driving the anomaly.
A collapse of the AMOC could sharply cool Europe, disrupt tropical rainfall and harvests, and raise sea levels along the U.S. East Coast, though outside scientists said the paper is unlikely to end the debate.
Could a slowing Atlantic current plunge Europe into a mini ice age?
Has the Atlantic's vital ocean current already passed its irreversible tipping point?
With crucial monitoring now at risk, how will we see the Atlantic's collapse coming?
Approaching the AMOC Tipping Point: The North Atlantic Cold Blob, Climate Risks, and Adaptation Strategies
Overview
Recent discoveries in 2025-2026 highlight a strange cooling patch, known as the 'cold blob,' in the North Atlantic, even as the global ocean continues to warm due to human-induced greenhouse gases. This anomaly is closely linked to the weakening of the Atlantic Meridional Overturning Circulation (AMOC), a vital ocean current system. Scientists have only been able to directly monitor AMOC since 2004, giving them a short record and making it hard to predict its long-term changes. Despite this, strong evidence shows the AMOC is weakening, raising serious concerns about future climate impacts.