Likely collapse of critical Atlantic current

The collapse of a critical Atlantic current can no longer be considered a low-likelihood event, new research has concluded, making deep cuts to fossil fuel emissions even more urgent to avoid the catastrophic impact.

The Atlantic meridional overturning circulation (AMOC) is a major part of the global climate system. It brings sun-warmed tropical water to Europe and the Arctic, where it cools and sinks to form a deep return current. The AMOC is already weakening as a result of the climate crisis.

A new analysis of climate models run beyond 2100 to 2300 and 2500 shows that the tipping point that makes an AMOC shutdown inevitable is likely to be passed in 10 to 20 years, but that the collapse itself may not happen until 50 to 100 years later.

If carbon emissions continued to rise, 70% of the model runs led to collapse, while intermediate emissions resulted in collapse in 37% of the models. Even in the case of low future emissions respecting the Paris agreement, an AMOC shutdown happened in 25% of the models. The AMOC slows drastically by 2100 and completely shuts off thereafter. Beyond the tipping point in the next decade or two, the shutdown of the AMOC becomes inevitable owing to a self-amplifying feedback.

The shutdown risk is more serious than many people realise. AMOC collapse would shift the tropical rainfall belt on which many millions of people rely to grow their food, plunge western Europe into extreme cold winters and summer droughts, and add 50cm to already rising sea levels. Even a 10% risk of an AMOC collapse would be far too high.

Scientists have already spotted warning signs of a tipping point with a downward trend over the past five to 10 years, consistent with the models’ projections. Air temperatures are rising rapidly in the Arctic because of the climate crisis, meaning the ocean cools more slowly there. Warmer water is less dense and therefore sinks into the depths more slowly. This slowing allows more rainfall to accumulate in the salty surface waters, also making it less dense, and further slowing the sinking, forming the feedback loop. The true figures could be even worse, because the models did not include the meltwater from the Greenland ice cap that is also freshening the ocean waters.

Even if a collapse is uncertain, a major weakening is expected, and that alone could have serious impacts on Europe’s climate in the decades to come.

SOURCE: based on Damian Carrington in The Guardian, 28 August 2025. https://www.theguardian.com/environment/2025/aug/28/collapse-critical-a…

ORIGINAL PAPER: Sybren Drijfhout, Joran R Angevaare, Jennifer Mecking, René M van Westen and Stefan Rahmstorf. Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections. Environ. Res. Lett. 20 (2025) 094062 28 August 2025. https://iopscience.iop.org/article/10.1088/1748-9326/adfa3b/pdf