The Atlantic Meridional Circulation (AMOC) is a system of ocean currents in the Atlantic Ocean, which includes the well-known Gulf StreamWarm salt water flows near the surface from the tropics northward to Europe, where it As the water cools, its density increases and it sinks to the bottom. This creates a deep current of cold water heading back south. This ocean "heat carrier" ensures that northern and western Europe (e.g. the British Isles or Scandinavia) have much milder winters than they would without this warm current. To give you an idea – the climate of London is significantly warmer than the climate of cities at the same latitudes in Canada or Russia. The AMOC also affects precipitation zones and overall global weather; it is among key elements of Earth's climate, whose sudden shift would have global consequences.

Signals of slowdown and risk of AMOC collapse

Scientists have been observing signs for several years that the AMOC is weakensMeasurements and reconstructions indicate that the current strength of this circulation is probably the weakest in the last ~1600 years. In the North Atlantic, a so-called "warming hole" – the area south of Greenland where, unlike the rest of the world, the ocean is not warming, but cooling. This is one of "fingerprints" A weakening AMOC: slowed heat transport northwards is causing unusually cold water in the region, while unusually warm water is accumulating off the east coast of the US. These signs of circulation “detuning” are warning signs for climatologists.

Is it possible that we are approaching a tipping point? Several recent studies from 2021–2023 have suggested that the AMOC may be approaching a critical tipping point, after which the flow could stop completely or change significantly. For example, a team of Danish scientists led by Peter Ditlevsen analyzed long-term data on ocean temperatures and concluded that with continued greenhouse gas emissions, there is a risk AMOC collapse around the middle of the 21st century – most likely around 2050 (with an interval of 2025 to 2095). In other words, according to this study, there may be collapse within this century with a ~95% probability (assuming no action to reduce emissions). Ditlevsen warns that this is a potentially huge change: “I think we should be really careful… the AMOC hasn’t been turned off for 12,000 years.” This threat ranks it among the most serious climate threats tipping elements – critical points that we must try to avoid at all costs.

However, it should be added that not all experts agree with such an early date for the collapse. Other research suggests, on the contrary, that a complete shutdown of the AMOC in the 21st century is unlikelyA major study by British scientists from the Met Office and the University of Exeter (published in early 2025 in the journal Nature) found that the AMOC should be able to withstand even significant warming – at least until the end of this century. Model simulations in this work showed that even with extreme warming (a scenario with a fourfold CO₂ concentration), the flow would weaken significantly, but not to its complete extinctionLead author Dr. Jonathan Baker says their findings suggest that the AMOC “appears to be resilient to pressures” and, although it will weaken, a sudden collapse in the next 75 years is unlikelyThis conclusion is consistent with the latest assessment report of the Intergovernmental Panel on Climate Change (IPCC), which states: AMOC is unlikely to collapse sharply in the 21st century (statement with "medium certainty").

How is it possible that scientific studies have come to such different scenarios? The difference is partly in the methods: The "camps" of scientists are not yet unified. Some teams (such as Ditlevsen and colleagues in Copenhagen and a group from the Royal Netherlands Meteorological Institute KNMI) have used unconventional statistical analyses of historical data and highly detailed, fine-resolution models to suggest a possible near-break. Other teams (such as the aforementioned Met Office/Exeter) have compared dozens of global models and identified stabilizing influences that will keep some of the ocean circulation going even as it warms. Moreover, the definition "AMOC collapse" may vary: whether it is a complete stoppage of all branches of the circulation, or "only" a significant weakening of the density-driven (so-called thermohaline) component. The fact remains that almost all projections agree on continued weakening heat flow to the north. Debate so it's not about whether AMOC will change, but how much and how fastAs oceanographer Alessandro Silvano aptly summarized: “The question of whether the AMOC could collapse is one of the most burning in the scientific community – especially when it comes to the horizon of the next century. Some studies indicate the proximity of the tipping point, others indicate greater resilience of the system… So there is currently a debate about a possible collapse, while AMOC weakening is considered very likely".

Timeline: Even if a complete stoppage of circulation were to occur, It probably wouldn't happen overnight.The ocean reacts slowly, has great inertia. Experts warn that a complete shutdown would take decades, maybe centuries – not like a Hollywood movie script. The pace of warming and the supply of freshwater from melting ice will play an important role. Good news is that if we could significantly reduce emissions and slow down global warming, we could delay the AMOC tipping point or not cross it at all. In other words, future developments is not firmly linked – we can still influence it by meeting the goals of the Paris Agreement (which is emphasized by the authors of all studies, regardless of their results).

What would a collapse mean for Europe and the world?

Since AMOC distributes heat to Europe, its significant weakening or cessation would bring significant cooling of the climate in Europe, especially in the northern and western partsAccording to climatologist Stefan Rahmstorf, Europe would find itself in a situation similar to Younger Dryas – the period ~12,000 years ago, when, due to the interruption of ocean circulation, they suddenly returned icy conditions in parts of the Northern Hemisphere. Records from that time show decreases in average temperatures of ~10 °C over several decades. Modern high-resolution model simulations recently conducted by scientists similarly suggest that without AMOC, northern Europe would cool radically – within a few decades, winter temperatures would drop by 10 to 30°C and the climate would change completely. It is figuratively stated that London would have a climate like today's Stockholm, and Stockholm like SiberiaIn addition to a bitter winter, Europe would likely see new weather extremes: for example, even stronger windstorms (as the greater temperature difference between the cooling Atlantic and the warmer south would drive more violent storms) and, conversely, possible droughts in some areas in the summer. Simulations suggest that, for example, Ireland and Britain could experience a decrease in average temperature of ~2–4°C (mainly in winter) following a significant weakening of the AMOC, drier summers and, conversely, wetter winters on the west coast (due to more frequent storms from the Atlantic). In in the extreme case of complete collapse The cooling and changing weather patterns would seriously disrupt agriculture – crops in Britain and across northern Europe would be threatened by crop failure and frost.

Some global impacts would also be felt by the rest of the world. Models show that a cooler North Atlantic would shift the tropical rain belt (the so-called intertropical convergence zone) further south. This would likely disrupted the monsoons in areas such as West Africa, India or Amazonia – it would rain elsewhere and at different times than the ecosystems and agriculture there are used to. Scientists estimate that, for example, The monsoon in the Sahel would weaken for a whole century forward. Furthermore, a decrease in ocean temperature could affect polar vortex over the Arctic, which would indirectly affect the weather in North America. And last but not least, sea level would change regionally by the rearrangement of ocean currents – it would increase off the east coast of the USA (because today a strong current there "sucks" some of the water north). In short, the collapse of the AMOC would a domino effect affected the entire climate of the planet – that's why it's referred to as one of the most critical climate tipping points.

Will this be a new ice age?

When reading the above scenarios, many people may imagine disaster movies as The day after that and the question arises: Are we facing a new ice age in Europe? The experts' answer is: probably not in the true sense of an "ice age", although regional cooling would be drastic. Under the term ice age usually refers to a global glaciation lasting for millennia. That doesn't seem to be happening – the global climate will continue to be dominated by a warming trend due to greenhouse gases. The cooling caused by the AMOC outage would locally It has counteracted global warming, but it doesn't mean the whole Earth will freeze. Even in Europe, it would look more like a conflict of two processes: temperatures would fall compared to today, but at the same time other effects of global climate change (e.g. weather extremes) would still be present. Some models even suggest that the decrease in flow could just slow down the warming of Europe, not completely reverse the trend – the impact of global warming could still prevail, especially in the summer months. Climatologist Richard Marsh warns that The cooling of the North Atlantic would partially offset global warming, but it doesn't mean anything good. – it would disrupt the established climate and bring unpredictable phenomena. In short, don't expect Bratislava or Paris to fall into eternal winter like during the continental ice ageRather, northern Europe would have acquired the climate that the far northeast has today – winters would have been harsher, summers perhaps colder and drier, but snow and glaciers would not have covered Europe year-round as they did 20,000 years ago.

At the same time the pace of change would not be immediateIf the AMOC were to stop, it would happen gradually over many years. Experts say it would take at least several decades, if not centuries. That's still extremely fast by geological standards, but still slower than in a Hollywood movie where everything freezes in a week. Society would have some (albeit short) time to adapt – but only if we are prepared for such a scenario. Scientists emphasize that already partial weakening flow can mean chaos for human systems (agriculture, energy, infrastructure), so there is no need to wait for a complete collapse for problems to arise. Therefore, it is important to monitor the development of the AMOCCurrently, intensive measurements of currents in the Atlantic are underway (the RAPID buoy system has been running since 2004) and scientists are looking for the so-called early warning signs Several independent indicators are warning that "Maybe we're not far from it"At the same time, however, new knowledge about ocean mechanisms (e.g. the role of winds in the Southern Ocean) gives hope that the system could be a little more durablethan we thought. Conclusion? Climatologists agree that Atlantic circulation will weaken – and probably already in this century – what mitigate the warming of Europe, but will not turn it into a new ice age. A complete cessation of flow is, although unlikely scenario, well not excluded – and given its consequences, we must take it seriously. Experts therefore appeal that the most sensible thing to do is precautionary measure: keep global warming as low as possible so that we can avoid, by a large margin, the wobble of this oceanic heart of our climate.

AMOC weakening likely won't literally trigger a new ice age, but could bring a "little ice age" for northern and western EuropeThe chances of a complete collapse in the 21st century are estimated differently by different studies – from a real threat in the coming decades to a scenario of “not earlier than in a hundred years or not at all”. However, they all agree that The Atlantic is already showing worrying changes a preventive emission reduction is the best strategy to prevent worst-case scenarios. So instead of panicking about an immediate ice apocalypse, we should focus on closely monitoring ocean trends and quickly addressing the causes – so that Europe does not have to face an unexpected climate cooling in the midst of global warming. Spring

Sources used: Ditlevsen et al. (2023, Nature Comm.); Baker et al. (2025, Nature); statements by experts (Rahmstorf, van Westen, Silvano, Marsh) from the Science Media Centre; news The Guardian, bne IntelliNews, Live Science; Met Office/Exeter and IPCC scenarios. (All citations in square brackets refer directly to these sources.)