A collapse in the Atlantic Meridional Overturning Circulation (AMOC) would be catastrophic, bringing “ice age” winters to Europe, raising sea levels in North America and disrupting vital monsoons in Africa and Asia.
But there is a sliver of good news: a climate-driven collapse of the AMOC might not be permanent. The AMOC could weaken significantly under rising global temperatures over the coming decades, but it could recover its strength just as quickly if global cooling occurs.
“There’s a very linear relationship between the global mean temperature and the AMOC response,” says Chuncheng Guo at the Danish Meteorological Institute. “When people talk about AMOC tipping, most of the previous studies are only looking at warming scenarios… but they didn’t actually test what if they reversed the forcing? Would the AMOC stay in that collapsed state or not?”
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Read moreThe collapse of the AMOC would be catastrophic. How will we know when it’s coming?
The AMOC is a vital ocean current that sustains Europe’s temperate climate. Together with colleagues, Guo used a state-of-the-art climate model to simulate what would happen to the AMOC’s strength as global temperatures rise in response to carbon emissions. The simulation includes melting of the Greenland ice sheet as a factor, as well as higher air temperatures.
The team modelled a temperature increase of 0.2°C per decade, slightly slower than the current rate of warming, and found that although the AMOC would weaken significantly over the coming centuries, it wouldn’t shut down entirely. The AMOC wouldn’t be totally extinguished even with up to 10°C of warming, Guo says.
If the world reached net zero emissions and then started to cool the global climate, for example by removing huge amounts of carbon from the atmosphere and putting it in long-term storage, the AMOC would start to strengthen within decades.
But the level of carbon removal needed would be vast. Currently, the world removes around 2 million tonnes of carbon per year, equivalent to 0.1 per cent of humanity’s annual emissions, via technologies such as direct air capture and enhanced weathering. This would need to increase to 45 petagrams per year, equivalent to 100 per cent of current total annual emissions, to deliver global cooling at a rate of 0.2°C per decade.
“AMOC reversibility does not mean safety, because we really need a huge, huge amount of carbon dioxide removal to achieve that cooling rate,” says Guo. “That is not something we can achieve with today’s technology.”
More radical cooling options, such as dimming the sun using solar radiation management, might be necessary to deliver cooling on this scale, says René van Westen at Utrecht University in the Netherlands.
Uncertainty about when or even if the Atlantic Meridional Overturning Circulation, a vital ocean current, might collapse has been an excuse to ignore the risk, but that actually makes it even more important that we act now
But Van Westen warns that restarting the AMOC after it has reached a collapsed state would plunge Europe’s climate further into chaos, exposing it to accelerated warming after a period of dramatic cooling.
Meanwhile, the results are based on just one climate model, which might be overestimating the stability of the AMOC. However, the findings tally with the results of a study published in July 2026, which also found that AMOC slowdown could be reversed by reducing levels of CO2 in the atmosphere.
The findings are part of an international project to study and model tipping-point risks. Researchers in Germany are now rerunning the same experiment using 10 different climate models to see how the results vary.
Journal Reference:Science Advances DOI: 10.1126/sciadv.aee5373