New Study Suggests Atlantic Current May Already Be Locked Into Collapse

A pre-print study posted on Earth ArXiv used a single climate-ocean model to explore how past and unavoidable future emissions could “lock in” the eventual collapse of the Atlantic Meridional Overturning Circulation (AMOC). The authors report a >=10 % probability that collapse is already committed, rising to 23 % under more severe Greenland-ice-melt assumptions and reaching 100 % by the end of the century if emissions continue unabated.

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The AMOC transports warm, salty water northward in the Atlantic and returns cold, dense water southward at depth, redistributing heat from the tropics to the Arctic. Its strength depends on the formation of deep, cold, salty water near Greenland; accelerated meltwater freshens the surface, weakening this process. Continued greenhouse-gas-driven warming amplifies sea-surface temperature, ice melt, and precipitation changes that erode the salinity and temperature gradients sustaining the circulation.

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• 10 % chance of inevitable collapse even if emissions peak in 2025.

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• 23 % probability under high-melt scenarios; 100 % likelihood by 2100 in the worst-case pathway.

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• Research published in April estimates a 43 %–58 % slowdown of the AMOC by 2100, a weakening 60 % stronger than the multi-model average.

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If the AMOC were to shut down, sea levels could rise dramatically along the U.S. East Coast, and northern Europe could experience temperature drops of 9 – 27 °F (5 – 15 °C). Global climate patterns would shift, producing more severe storms, altered tropical rain belts, drought in some regions, and flooding in others.

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A June-published study found no evidence that the AMOC is headed toward an abrupt collapse, even under high-emissions scenarios with substantial Greenland melt, highlighting ongoing disagreement about the system’s near-term trajectory. While scientists concur that the AMOC is weakening, the timing and inevitability of a full shutdown remain contested.

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• “Our analysis shows that there is a [greater than] 10% probability that collapse is already committed, regardless of the speed of any feasible future mitigation, and rising steeply under continued emissions,” — Study authors

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• “Stefan Rahmstorf, an oceanographer at the Potsdam Institute for Climate Impact Research in Germany who was not involved in the research, noted in an X post that the study is based on a single model.” — Stefan Rahmstorf, oceanographer, Potsdam Institute for Climate Impact Research

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• “However, he said its conclusions are plausible based on overall knowledge of how fragile the AMOC currently is.” — Stefan Rahmstorf, oceanographer, Potsdam Institute for Climate Impact Research

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• “Research published in April found that the AMOC is on track for a 43% to 58% slowdown by 2100—a substantial weakening that is 60% stronger than the average estimate of all climate models.” — article summary

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• “A study published in June did not find evidence that the AMOC is headed toward an abrupt collapse, even under a high-emissions scenario with substantial Greenland ice melt.” — article summary

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