Scientists warn that the Gulf Stream system could shut down after 2100, driving extreme winters, drying summers, and chaotic rainfall shifts.
In scenarios where greenhouse gas emissions remain high, the Atlantic Meridional Overturning Circulation (AMOC) could completely collapse sometime after the year 2100. The AMOC, which includes the Gulf Stream, is one of the most important systems of ocean currents on Earth.
A new study involving the Potsdam Institute for Climate Impact Research (PIK) warns that its shutdown would sharply reduce the ocean’s ability to transport heat northward. The result would be much drier summers and far harsher winters in northwestern Europe, along with major changes to rainfall patterns in the tropics.
“Most climate projections stop at 2100. But some of the standard models of the IPCC – the Intergovernmental Panel on Climate Change – have now run centuries into the future and show very worrying results,” says Sybren Drijfhout from the Royal Netherlands Meteorological Institute, the lead author of the study published in Environmental Research Letters.
“The deep overturning in the northern Atlantic slows drastically by 2100 and completely shuts off thereafter in all high-emission scenarios, and even in some intermediate and low-emission scenarios. That shows the shutdown risk is more serious than many people realise.”
Ocean Conveyor Belt and Its Tipping Point
The AMOC functions like a massive conveyor belt. Warm tropical waters travel northward near the surface, while colder, denser water sinks and returns south at depth. This circulation keeps Europe’s climate relatively mild and shapes weather patterns across the globe.
In the new simulations, the critical tipping point comes when deep winter convection collapses in the Labrador, Irminger, and Nordic Seas. Rising global temperatures reduce how much heat escapes from the ocean in winter because the air is not cool enough. This weakens the vertical mixing of ocean waters. As a result, the surface remains warmer and lighter, which makes it less able to sink and mix with the colder waters below. That loss of mixing disrupts the AMOC and reduces the flow of warm, salty water moving north.
Self-Reinforcing Feedback Loops Intensify
In northern regions, then, surface waters become cooler and less saline, and this reduced salinity makes the surface water even lighter and less likely to sink. This creates a self-reinforcing feedback loop, triggered by atmospheric warming but perpetuated by weakened currents and water desalination.
“In the simulations, the tipping point in key North Atlantic seas typically occurs in the next few decades, which is very concerning,” says Stefan Rahmstorf, Head of PIK’s Earth System Analysis research department and co-author of the study. After the tipping point, the shutdown of the AMOC becomes inevitable due to a self-amplifying feedback. The heat released by the far North Atlantic then drops to less than 20 percent of the present amount, in some models almost to zero, according to the study.
Lead author Drijfhout adds that “recent observations in these deep convection regions already show a downward trend over the past five to ten years. It could be variability, but it is consistent with the models’ projections.”
Emission Cuts Could Still Reduce the Risk
To arrive at these results, the research team analyzed CMIP6 (Coupled Model Intercomparison Project) simulations, which were used in the latest IPCC Assessment Report, with extended time horizons from 2300 to 2500. In all nine high-emission simulations, the models evolve into a weak, shallow circulation state with the deep overturning shutting down; this result is produced in some intermediate and low-emission simulations as well. In every case, this change follows a mid-century collapse of the deep convection in the North Atlantic seas.
Global Consequences and the Urgent Call
“A drastic weakening and shutdown of this ocean current system would have severe consequences worldwide,” PIK researcher Rahmstorf points out. “In the models, the currents fully wind down 50 to 100 years after the tipping point is breached. But this may well underestimate the risk: these standard models do not include the extra fresh water from ice loss in Greenland, which would likely push the system even further. This is why it is crucial to cut emissions fast. It would greatly reduce the risk of an AMOC shutdown, even though it is too late to eliminate it completely.”
Reference: “Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections” by Sybren Drijfhout, Joran R Angevaare, Jennifer Mecking, René M van Westen and Stefan Rahmstorf, 28 August 2025, Environmental Research Letters.
DOI: 10.1088/1748-9326/adfa3b
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