Far below the restless surface of the Atlantic, a hidden giant moves quietly, day after day. This giant is not a creature but a current—an immense conveyor belt of water that shuttles heat, salt, and life itself across the globe. Known as the Atlantic meridional overturning circulation, or AMOC, it is one of Earth’s most important lifelines. It includes the Gulf Stream, famous for bringing warmth from the tropics up toward Europe, and it shapes weather patterns on continents thousands of kilometers away.
Without it, Europe would be colder, the tropics would be wetter or drier in unexpected ways, and storm patterns across the globe would shift dramatically. For thousands of years, this system has been stable, keeping the climate relatively balanced. But now, new research suggests that this silent giant may be stumbling. Under high-emission scenarios, the AMOC could grind to a halt after the year 2100. And if that happens, the consequences would reverberate across every corner of the planet.
Beyond 2100: Looking Further Into the Future
Most climate projections we hear about stop at the year 2100. That year has become a kind of symbolic finish line in public discussions of global warming. But of course, the Earth will not stop spinning on New Year’s Eve of 2099. The centuries that follow matter deeply for our descendants, and climate models are now stretching further into the future to show us what might lie ahead.
What they reveal is alarming. According to simulations conducted with contributions from the Potsdam Institute for Climate Impact Research, the deep overturning circulation in the North Atlantic slows dramatically by 2100 and, under high-emission pathways, shuts down entirely afterward. Even in some intermediate and lower-emission scenarios, collapse is still possible. The risk is not distant science fiction—it is a looming possibility, with tipping points potentially reached within just a few decades.
As lead author Sybren Drijfhout explains, “The deep overturning in the northern Atlantic slows drastically by 2100 and completely shuts off thereafter in all high-emission scenarios. That shows the shutdown risk is more serious than many people realize.”
The Ocean Conveyor Belt
To grasp what is at stake, we need to understand what the AMOC actually does. Imagine the ocean as a giant conveyor belt. Warm, salty waters flow northward near the surface, releasing heat into the atmosphere. This is part of what keeps European winters milder than those at similar latitudes in Canada. Once the water cools and becomes denser, it sinks into the depths and flows southward, completing the loop.
This circulation not only moderates Europe’s climate but also shapes rainfall patterns across the tropics, influences monsoons, and plays a role in regulating the entire planet’s climate engine. It is as if the Earth’s climate has a hidden heartbeat—and the AMOC is that pulse.
But this pulse depends on a delicate balance between heat and salt. And climate change is disturbing both.
The Tipping Point in the North Atlantic
The new study highlights the trigger point: a collapse of deep convection in winter in the Labrador, Irminger, and Nordic seas. Under normal conditions, winter cold draws heat from the surface of the ocean, making water dense enough to sink. This sinking drives the circulation. But as the atmosphere warms, it steals less heat from the sea. The surface water stays warmer and lighter, resisting the plunge downward.
Meanwhile, melting ice from Greenland and increasing rainfall are freshening the surface waters, making them even less salty and less dense. The combination creates a dangerous feedback loop. The surface refuses to sink, deep convection stalls, and the conveyor belt weakens further. Once that process crosses a critical threshold, the AMOC does not simply slow—it collapses.
Stefan Rahmstorf, a leading climate scientist from PIK, describes it bluntly: “In the simulations, the tipping point in key North Atlantic seas typically occurs in the next few decades, which is very concerning.”
What Collapse Would Mean
If the AMOC were to shut down, Europe would no longer be cushioned by warm ocean currents. Summers could grow hotter and drier, while winters might become bitterly cold and extreme. Weather across the Atlantic basin would destabilize. The tropical rain belts could shift, causing devastating droughts in some regions and flooding in others. Croplands that billions rely on could fail, fueling hunger and migration.
The global consequences extend beyond weather. Ocean ecosystems depend on the steady churning of nutrients carried by currents. Without the overturning circulation, fisheries could collapse, threatening food security. The entire planet’s carbon cycle could be disrupted, worsening climate change rather than easing it.
Already Seeing the Signs
For many years, the collapse of the AMOC was considered a possibility far on the horizon, perhaps thousands of years away. But the new simulations, backed by recent observations, tell a different story. Measurements in the North Atlantic already show a downward trend in deep convection over the past decade. It could be natural variability. Or it could be the first tremors of a system approaching its tipping point.
If the latter is true, then the window to prevent collapse is narrowing. As Drijfhout warns, “It could be variability, but it is consistent with the models’ projections.”
Why This Matters Beyond Europe
It might be tempting to view the AMOC as a regional concern—a problem mainly for Europe. But the truth is, no one is beyond its reach. The AMOC is part of a global network of currents that regulate climate across the planet. Its collapse would alter monsoon systems that feed billions in Asia and Africa. It would destabilize the Amazon rainforest, one of Earth’s great carbon sinks. It would amplify the already mounting risks of sea-level rise along North America’s Atlantic coast.
In short, a shutdown of this current would not just reshape Europe’s winters. It would redraw the map of global climate, in ways that human civilization is not prepared for.
Cutting Emissions: The Only Lifeline
The message from scientists is clear: the risk is real, the consequences are dire, and the path we choose now will shape the outcome. Every ton of carbon dioxide emitted into the atmosphere pushes the climate system closer to thresholds it may not recover from.
The simulations analyzed extend as far as the years 2300 to 2500. In all nine high-emission scenarios, the AMOC shuts down. Even in some intermediate and low-emission pathways, collapse still occurs. The models may even underestimate the danger, because they do not fully account for Greenland’s accelerating ice melt, which is pouring additional freshwater into the North Atlantic.
That is why scientists emphasize urgency. As Rahmstorf puts it: “A drastic weakening and shutdown of this ocean current system would have severe consequences worldwide. Cutting emissions fast would greatly reduce the risk of an AMOC shutdown, even though it is too late to eliminate it completely.”
A Choice for Humanity
Science does not often deal in apocalyptic warnings. It is cautious, conservative, and precise. But when a system as vast as the AMOC is at risk of collapse, caution becomes urgency. The oceans are telling us something, and the models are translating that message with stark clarity: business as usual could dismantle the very currents that cradle our climate.
And yet, the future is not written. The tipping point may be close, but it has not yet been crossed. Each year that emissions are reduced, each step toward renewable energy, each forest protected and each ton of carbon kept underground, pushes the odds back in our favor.
The AMOC’s fate is not just a scientific puzzle. It is a story about our choices, our courage, and our willingness to listen to warnings before it is too late. If the ocean is the heartbeat of the planet, then saving the AMOC is nothing less than keeping that heart alive.
More information: Sybren Drijfhout et al, Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections, Environmental Research Letters (2025). DOI: 10.1088/1748-9326/adfa3b
