Scientists are increasingly worried that a vast system of ocean circulation, which delivers warmth to northern Europe and impacts climate globally, is at risk of collapse. Mounting evidence suggests it may be nearing a tipping point, though the research is far from certain.

By Nicola Jones • May 7, 2026

As the world careens past our hoped-for target of 1.5 degrees Celsius warming, scientists are growing increasingly alarmed that we may be nearing a dramatic, long-feared “tipping point” — a moment when the main ocean current in the Atlantic Ocean becomes destined to shut down, clamping off the primary source of warmth for northern Europe and playing havoc with the global climate.

Such a scenario has been a concern for many decades, but the issue is now heating up. “I have personally researched this for 35 years,” says Stefan Rahmstorf, a physical oceanographer at the Potsdam Institute for Climate Impact Research in Germany. “For the first 30 years we considered this a low likelihood event — I would have said a 5 percent chance of occurring. It’s more like 50/50 now. I would even say more likely than not.”

The main ocean current in the Atlantic — the Atlantic Meridional Overturning Circulation — is one of the most powerful drivers of heat around the globe. The AMOC is the reason that northern Europe is so temperate, a couple of degrees warmer than it ought to be given its latitude.

If the AMOC shuts down, its flow slowing to a near halt, the modeled consequences are catastrophic: Europe dries out, affecting agriculture and wildfires; the temperature difference between northern and southern Europe jacks up by a whopping 7 degrees F (4 degrees C), supercharging storms; the vital African and Asian monsoons weaken; and more. An AMOC collapse is also predicted to stir up the Southern Ocean, which could spew out more of its deep carbon into the air, further warming the globe.

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