The Gulf Stream holds tantalizing clues about when other central Atlantic currents may collapse due to climate change, a new study finds.
Originating in the Gulf of Mexico and leaving the US East Coast near Cape Hatteras in North Carolina, the Gulf Stream is a branch of the Atlantic Meridional Overturning Circulation (AMOC) – a giant system of ocean currents that brings warmth to the Northern Hemisphere and Europe in particular.
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“First, you have this very gradual northward drift (of the Gulf Stream), which is related to some AMOC weakening, but apparently there is also this jump when the AMOC becomes too weak, which is this early warning indicator,” lead author of the study. René van Westena postdoctoral fellow in climate physics at Utrecht University in the Netherlands, told LiveScience.
Unlike other currents that form the AMOC, the Gulf Stream is wind-driven. After passing Florida, it follows the US east coast north to Cape Hatteras and then turns east into the North Atlantic. Although the Gulf Stream is a surface current, its position is controlled by much deeper currents that also belong to the AMOC and create dense eddies as they interact with the layers above. These spirals push the Gulf Stream as a whole southward – but when the AMOC weakens and the eddies loosen, the Gulf Stream can begin to drift northward.
To explore these effects further, van Westen et Henk Dijkstraprofessor of physical oceanography at the University of Utrecht, simulated an AMOC collapse in a very high-resolution ocean model over the Gulf Stream. In the climate models typically used to study the AMOC, the Gulf Stream is “smoothed out, so you hardly see any features and the dynamics are not well captured,” van Westen said.
The researchers triggered an AMOC collapse in the model that was much more gradual than the collapse humans can cause by warming the Earth and accelerating the melting of Arctic ice, which prevents the formation of deep ocean currents. They observed the Gulf Stream’s response in unprecedented detail, revealing for the first time an extremely abrupt, northward shift of the current 25 years before the start of the collapse.
The results were published on 26 February in the journal Communication Earth and the environment.
The researchers found two stages in the Gulf Stream’s response, both measured off Cape Hatteras at 71.5 degrees west longitude. First, as the AMOC gradually weakened over 392 simulated years, the Gulf Stream moved 133 kilometers northward. Second, as the AMOC continued to weaken over two more simulated years, the Gulf Stream suddenly jumped northward by 136 miles (219 km). This abrupt shift occurred only 25 years before the start of the AMOC collapse, suggesting that it can be used as an early warning signal to predict the collapse.
While the two stages may be realistic, the time lag between the abrupt Gulf Stream shift and an AMOC collapse is unlikely to actually be 25 years in real life, van Westen said. That’s because the model didn’t account for global temperature rise, which accelerates the collapse of the AMOC; the model only simulated an increase in freshwater in the North Atlantic.
A northward drift of the Gulf Stream has implications for marine ecosystems that are currently north of the current in colder water, but may soon end up south of the current in warmer water. The drift could also exacerbate sea-level rise along the east coast, van Westen said.
Already underway
The researchers then analyzed satellite data to determine whether the Gulf Stream has already begun to move north. “We found this relationship within our climate model, and now the next step was to see if these results show up in observations,” said van Westen. “What we found in observations is that, yes, indeed, the Gulf Stream has shifted northward over the past three decades.”
This finding is more evidence that the AMOC is weakening and means we are in the first phase of the Gulf Stream’s response, van Westen said. Natural climate and atmospheric variability may have contributed to the slow drift, but these contributions are small compared to the AMOC’s weakening, he added.
It is unclear when the transition to the second phase of the Gulf Stream response will occur, but satellites are in place to detect this switch if and when it occurs. The next task for researchers is to work out the true lag time between this second phase and the AMOC collapse, so that the second phase can serve as a robust warning indicator, van Westen said.
The study is the most in-depth analysis of the potential consequences of an AMOC collapse on the Gulf Stream to date, but there are some caveats, said Maya Ben-Yamia climate scientist at the Technical University of Munich and the Potsdam Institute for Climate Impact Research in Germany who was not involved in the research.
“This paper definitely points to changes in the Gulf Stream as a possible warning signal, but much more work needs to be done to confirm that, for example by looking across different models,” Ben-Yami told LiveScience in an email.
It is possible that the abrupt northward shift could occur without the AMOC collapsing down the line, in which case it may not be an early warning indicator, but rather a response to the weakening, she said.
In addition, the rate of AMOC weakening in the study was likely slower than would be expected under future warming conditions, meaning the 25-year lag may shrink to “almost nothing” and come too late to be a manageable warning signal, Ben-Yami said.
“Personally, I think it’s also useful to have a signal that just tells you that the tipping point has been crossed” without prior warning, but I would say that we still don’t know if changes in the Gulf Stream could be either type of signal, she said.
Van Westen, RM, & Dijkstra, HA (2026). Abrupt changes in the path of the Gulf Stream are a precursor to the collapse of the Atlantic Meridional Overturning Circulation. Communication Earth and the environment, 7(1), 197. https://doi.org/10.1038/s43247-026-03309-1
