Recent weeks have seen a wave of public commentary on the risk of AMOC collapse, most visibly through the People's Emergency Briefing; a documentary drawing on expert testimony delivered to UK politicians and civic leaders, and through widely shared online content drawing on the same underlying science.
The Atlantic Meridional Overturning Circulation (AMOC) has returned to the public spotlight, as it periodically does when a single study finds its way into headlines or film. We addressed the 2024 van Westen et al. study in a previous Spotlight article, and it is that study, and the projections it contains, that continues to anchor the most dramatic claims now in circulation.
Specifically, the People’s Emergency Briefing features Tipping Point projections of severe cooling across northwest Europe in the event of a full AMOC collapse, including winter temperature anomalies approaching −20°C in London and −30°C in Edinburgh. Public engagement with the risks posed by AMOC change is something EPOC researchers actively welcome. The reach of films, briefings and online content into communities, parliaments and civic institutions represents exactly the kind of public conversation that climate science needs to support. But it is precisely because that conversation matters that the scientific framing within it needs to be accurate.
Whether the AMOC is currently approaching a tipping point remains an open and actively contested question in the scientific literature.[1] The temperature projections cited in the briefing derive from modelling work by van Westen and Baatsen (2025).[2] Those projections represent equilibrium states expected to emerge well beyond 2200, under a single climate model and a highly idealised freshwater forcing scenario. They are not near-term projections, and the study itself has attracted careful expert commentary noting that warm summer extremes would continue to worsen under global heating even in a collapsed-AMOC world, meaning the full picture is considerably more complex.[3] Unfortunately, this crucial context was largely absent from the briefing.
The IPCC 6th Assessment Report concluded that an AMOC weakening through the 21st century is very likely, but assessed with medium confidence that an abrupt, full collapse will not occur before 2100.[4] Direct observations from the RAPID mooring array show a weakening trend of approximately 1 Sverdrup per decade since 2004, consistent with model projections, yet small relative to shorter-timescale variability and only marginally statistically significant.[4]
There is, thus, significant uncertainty in predicting the magnitude and timing of AMOC change. This matters because the risks associated with a sustained, gradual AMOC weakening are real and significant in their own right. McCarthy and Pörtner (2026)[5] revisit the landmark 2015 Rahmstorf study[6] which used a persistent cooling anomaly in the subpolar North Atlantic (observed while virtually every other ocean region warmed) as evidence that the AMOC had weakened during the twentieth century earlier than climate models had projected. That study was influential precisely because it pointed to a critical and unresolved uncertainty in the climate system. McCarthy and Pörtner assess what a decade of subsequent research has revealed about that finding, and highlight the genuine consequences of AMOC weakening: relative cooling in the North Atlantic, shifting precipitation patterns across the Atlantic-Europe sector, increased mid-latitude storminess, and sea level rise along European and North American coastlines.[5] McCarthy has noted publicly that single-study headlines on imminent AMOC collapse generate “seesawing” narratives that concern and confuse policymakers rather than equipping them to act, and has called for a broader, consolidated scientific voice to guide the public discourse.[7]
Iceland declared AMOC weakening an existential security threat in 2025.[8] The Nordic Council published a policy-relevant assessment of AMOC tipping risks in February 2026, calling for strengthened mitigation, long-term observational funding, and increased societal preparedness.[9] The AMOC in Focus initiative, a 60-scientist, 14-country assessment convened under JPI Oceans, is working to produce authoritative guidance for policymakers that draws on the full breadth of the literature rather than any single study.[10] A CLIVAR workshop later this year will bring the international research community together specifically to assess the plausibility and likely timescales of an AMOC collapse.[11]
EPOC’s contribution to resolving these uncertainties spans observations, proxies and modelling. The project’s work on AMOC transport variability, the mechanisms responsible for past circulation changes, and the conditions under which abrupt transitions might occur directly addresses the scientific gaps that make extreme scenarios both conceivable and difficult to constrain. Until those gaps are narrowed, placing dramatic projections from individual studies into their proper context is not an act of complacency. It is a precondition for the kind of credible, sustained policy engagement that AMOC science demands.
The risks are very real. Communicating them accurately is the most effective thing scientists can do.
[1] Hirschi, J. et al. (2026). Is the AMOC on course for shutdown? EPOC Spotlight. https://epoc-eu.org/is-the-amoc-on-course-for-shutdown/
[2] van Westen, R.M. & Baatsen, M.L.J. (2025). European temperature extremes under different AMOC scenarios in the Community Earth System Model. Geophysical Research Letters. https://doi.org/10.1029/2025GL114611
[3] Science Media Centre (2025). Expert reaction to modelling study on the impact of a weakened AMOC on the European climate. https://www.sciencemediacentre.org/expert-reaction-to-modelling-study-on-the-impact-of-a-weakened-amoc-on-the-european-climate/
[4] McCarthy, G.D. et al. (2025). Climate change impacts on ocean circulation relevant to the UK and Ireland. MCCIP Science Review 2025. https://doi.org/10.14465/2025.reu05.cir
[5] McCarthy, G.D. & Pörtner, H.-O. (2026). Atlantic exceptionalism in the twentieth century. Nature Climate Change, 16, 391–392. https://doi.org/10.1038/s41558-026-02608-x
[6] Rahmstorf, S. et al. (2015). Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation. Nature Climate Change. https://doi.org/10.1038/nclimate2554
[7] McCarthy, G.D. (2026). Exaggerated AMOC collapse headlines may cloud Ireland’s real storm and rain risks. Phys.org, 10 April 2026. https://phys.org/news/2026-04-exaggerated-amoc-collapse-headlines-cloud.html
[8] Reuters (2025). Iceland sees security risk, existential threat from Atlantic ocean currents, 12 November 2025. https://www.reuters.com/sustainability/cop/iceland-sees-security-risk-existential-threat-atlantic-ocean-currents-possible-2025-11-12/
[9] Nordic Council of Ministers (2026). A Nordic Perspective on AMOC Tipping. TemanNord 2026:504. https://pub.norden.org/temanord2026-504
[10] JPI Oceans & JPI Climate (2025). Shedding light on AMOC. https://www.jpi-oceans.eu/en/atlantic-meridional-overturning-circulation
[11] CLIVAR (2026). Workshop: Collapse of the Atlantic Ocean Circulation — Can it? Has it? Will it? https://www.clivar.org/events/workshop-collapse-atlantic-ocean-circulation-can-it-has-it-will-it