In climate science (and science in general), there is a phenomenon called feedback loops. These are processes through which the climate crisis intensifies itself. For example, Arctic ice melt. Rising surface temperatures are melting the Arctic glaciers at an unprecedented rate, releasing cold freshwater into the North Atlantic. The Atlantic Ocean houses a current that is the backbone of several important global weather patterns, essentially making agriculture viable for many places. This is called the Atlantic meridional overturning circulation or the AMOC. Scientists have been studying the AMOC for decades, and while the AMOC has been slowing down steadily over the last few decades, a recent study shows that the weakening may be worse than previously projected, which has led to many scientists worrying about a potential collapse.
Even as the AMOC slows, global weather patterns will change dramatically. In the event of a collapse, South Asia and Africa will experience a monsoon disruption, which will endanger food production and water supply for billions of people, in turn causing internal sociopolitical and economic turmoil. The eastern coast of the US will experience rapid sea level rise, the Amazon rainforest’s wet and dry seasons will flip, and Europe will experience a plunge in temperature which will impact agricultural production.
According to the current consensus as per the 6th Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC), projections indicate medium confidence that an abrupt AMOC collapse will not occur before 2100, though it cannot be ruled out with high confidence. The IPCC projects the AMOC will weaken by about 24% (range 4-46%) under low-emissions scenarios and 39% (range 17-55%) under very high-emissions scenarios by 2100.
The AR6 was released in 2023 and relies on the Coupled Model Intercomparison Project (CMIP) to assess the strength of AMOC, which shows weakening but the quantitative rate of weakening is not projected with high confidence. A 2026 study used four different observational constraint methods to reduce this uncertainty and found 51 ± 8% (90% probability) in the estimated AMOC slowdown, which means that the current is weakening at a rate that is ∼60% stronger than previously believed.
The collapse of AMOC is by no means a binary possibility but there is serious cause for concern. A 2025 paper highlighted a precursor event to the collapse where transition to the weakening of AMOC is preceded by “a mid-21st century collapse of maximum mixed-layer depth in Labrador, Irminger and Nordic Seas.” According to the findings, convection is currently transitioning from natural variability to terminal decline. The observational data shows downward trends in mixing depths over the last 5-10 years in all deep convection regions, which could be variability, but is consistent with model predictions.
To simplify, this is what the potential trigger could look like: in this decade, Arctic and Greenland melt accelerates, causing freshwater to enter the North Atlantic. The ocean surface gets less salty and the warming atmosphere means less winter cooling. By mid-century, the “engine” of the AMOC, i.e. deep convection, stops.
Every winter, cold air cools the ocean surface, making the cold surface water dense and heavy. It sinks down and pulls warm water north from the tropics (that’s the AMOC). This cycle maintains many global weather patterns. In the case that ice melt continues, surface water will no longer be salty enough to sink, even when it is cold. Water will only mix in the shallows, and deep convection will stop. The AMOC will continue to weaken through the next century, until it shuts down and the heat transport to Europe is essentially gone.
The implication of AMOC collapse is highly controversial in climate circles, but deep convection is a different story. It is worth noting that some scientists and climate change communicators are already ringing the alarm, and among them is an expert reviewer of the IPCC’s 5th Assessment Synthesis Reports and 1.5ºC Special Report, Dr. Peter Carter. In a recent episode of the Climate Emergency Forum on YouTube, Dr. Carter highlighted that IPCC models don’t include several major Earth feedback systems that could dramatically accelerate warming once triggered.
“The AMOC is one of these abrupt climate changes which has a dramatic tipping point. And unfortunately, and very oddly, none of these are included in the IPCC’s projection of global temperature increase and projection of impacts … they say we don’t know what’s going to happen. But even more importantly, thawing permafrost, which is emitting all three greenhouse gases, CO2, methane and nitrous oxide, that’s not included in the projections. There are warming peatlands [which produce] as much carbon as the permafrost and they are also emitting methane and also nitrous oxide, that’s not included. Also, the collapse of the Amazon rainforest, which is very, very close [because] the Amazon rainforest is now not acting as carbon sink. That’s not included.”
George Monbiot, an easily recognizable figure in climate journalism, criticized the lack of media coverage on the AMOC issue in a recent Guardian article, and summed up potential impacts to the United Kingdom in the event of a collapse:
“… the net impact in northern Europe would be periods of extreme cold – including events in which temperatures in London fall to -19C, in Edinburgh to -30C and in Oslo to -48C. Sea ice in February would extend as far as Lincolnshire. Our climate would change drastically, with the likelihood of far greater extremes, such as massive winter storms. Rain-fed arable agriculture would become impossible almost everywhere in the UK. This shift, on any realistic human scale, would be irreversible. Its speed is likely to outrun our ability to adapt.”
At this point in time, we must not let ourselves forget human patterns and how we ended up in the climate crisis in the first place. It was not incorrect scientific projections that led us to this reality, but rather the intentional diversion of attention from fossil fuel energy as the Exxon case revealed.
Disagreements around the quantitative probability of collapse and the potential implications distract from accounting for the conditions that may allow the conditions for collapse earlier than projected. The AMOC collapse can be triggered earlier than anyone imagined because of political choices that serve existing power structures even as they destroy habitability. One such example is the threat of industrialization of the Arctic under authoritarian regimes. As the US lifts Arctic drilling restrictions, or if Russia accelerates its Northern Sea Route development, the combined effect could result in massive black carbon deposition on Arctic ice from shipping and/or drilling operations. Black carbon darkens ice and accelerates melting, which in turn will impact freshwater flow and change the albedo, which reflects heat from the Earth.
Hypothetically, In a different scenario, given the precarious nature of international climate cooperation, solar geoengineering could be a potential threat to global climate stability. Without coordination, suppose a country conducts solar radiation management and ends up changing monsoons, and the affected country responds with counter-geoengineering. This could lead to a cascading effect of atmospheric circulation changes with altered precipitation patterns, causing salinity disruption over the Atlantic among several other issues. Although this is purely hypothetical, and perhaps not at all likely to happen, the UK has been conducting outdoor geoengineering experiments, and a private Israeli startup has garnered support worth $60 million.
Another what-if lies in keystone species. Antarctic krill populations are already declining, and they are crucial for transporting carbon to the deep ocean. In the event of their collapse, there will be reduced ocean carbon uptake leading to greater atmospheric warming and ice sheet instability. This could lead to a freshwater pulse into the Southern Ocean, which can affect the AMOC via global thermohaline circulation. Phytoplankton could similarly cause a massive reduction in ocean carbon uptake in the scenario that they are unable to access nutrients any longer because of ocean warming and stratification, leading to a runaway warming scenario.
Several more what-ifs lie in AI growth, agricultural collapse, continued conflict, or Arctic mineral extraction. The idea is to understand that our perils emerge almost exclusively from the system that we keep feeding and the information that we keep missing because of intentional redirection of our attention. It is now clearer than ever that human survival depends on the restructuring of the economic system, away from growth and towards regeneration. It is now more important than ever that we push against authoritarian regimes and global corporations who maintain the status quo to continue accumulating wealth at the expense of our literal future.
We are quite literally the last generation that can define the future of all humanity to come.
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