Coincidental with the runup to Halloween, climate alarmists are again filling the media with warnings about Atlantic Meridional Ocean Circulation (AMOC) collapsing and giving rise to an ice age.  They blame this on radiative forcing from increasing CO2 levels by humans using hydrocarbon fuels.  Some examples that may have caught your attemtion.

Satellites show some of the strongest evidence the AMOC is weakening, New Scientist, 26 October 2026

Key Atlantic currents could collapse this century, but the risk is missing from almost all national climate plans, The Conversation, 28 October 2026

AMOC collapse: The major climate threat missing from almost every country’s adaptation plans, MSN 2 November 2026

‘Too late to act’: Scientists warn critical Atlantic and Antarctic Ocean currents are collapsing, news.com.au 2 November 2026

AMOC: How the changing Atlantic could reshape our world, BBC 1 November 2026

Iceland Is War-Gaming an Ocean Current Collapse, Gizmodo 2 November 2026

Etc., Etc., Etc.

As readers may suspect, much of this bandwagon is triggered by a new paper from the alarmists at Potsdam led by Rahmsdorf.  And also unsurprisingly, it all depends on projections from climate models rather than observed realities.  The post provides a fact check from the real world by means of a peer-reviewed paper at Nature by A.J. Baker et al. (2026)  Continued Atlantic overturning circulation even under climate extremes.  Excerpts in italics with my bolds and added images.

Abstract

The Atlantic Meridional Overturning Circulation (AMOC), vital for northwards heat transport in the Atlantic Ocean, is projected to weaken owing to global warming, with significant global climate impacts. However, the extent of AMOC weakening is uncertain with wide variation across climate models and some statistical indicators suggesting an imminent collapse. Here we show that the AMOC is resilient to extreme greenhouse gas and North Atlantic freshwater forcings across 34 climate models.

Upwelling in the Southern Ocean, driven by persistent Southern Ocean winds, sustains a weakened AMOC in all cases, preventing its complete collapse. As Southern Ocean upwelling must be balanced by downwelling in the Atlantic or Pacific, the AMOC can only collapse if a compensating Pacific Meridional Overturning Circulation (PMOC) develops. Remarkably, a PMOC does emerge in almost all models, but it is too weak to balance all of the Southern Ocean upwelling, suggesting that an AMOC collapse is unlikely this century.

Our findings reveal AMOC-stabilizing mechanisms with implications for past and future AMOC changes, and hence for ecosystems and ocean biogeochemistry. They suggest that better understanding and estimates of the Southern Ocean and Indo-Pacific circulations are urgently needed to accurately predict future AMOC change.

Discussion

To understand how the AMOC is sustained under extreme climate forcing, and what causes differences in its weakened state across models and forcings, we quantify the AMOC’s upwelling pathways, which return deep North Atlantic waters to the surface either through Southern Ocean (SO) wind-driven upwelling or diffusion in the Atlantic and Indo-Pacific oceans. The SO wind-driven upwelling rate depends on the SO westerly wind strength that drives SO upwelling and on the opposing SO mesoscale eddy response, referred to as eddy compensation.

Our approach, which focuses on AMOC upwelling pathways rather than the mean state of the North Atlantic, offers fresh perspectives on the AMOC response. Although the AMOC’s Indo-Pacific upwelling pathway largely controls intermodel variations in AMOC decline in realistic scenarios, the impact of extreme forcing on upwelling pathway changes and thereby potentially AMOC resilience has not been explored. Here we assess how ocean circulation changes remote from the Atlantic affect the AMOC and its upwelling pathways in climate models.

Fig. 1 | Schematic and analysis method for AMOC upwelling pathways. a,b, Meridional overturning streamfunction in sverdrups (Sv (106 m3 s−1), with 2-Sv contour intervals) from the CMCC-ESM2 pre-industrial control simulation, highlighting the methodology for separating the AMOC’s upwelling pathways.

Streamfunctions are shown for the Atlantic (a) and Indo-Pacific (b) oceans north of 34.5° S (indicated by vertical dashed lines) and globally within the Southern Ocean (SO). The 0-Sv streamline is marked by a solid black line and the vertical green line at 34.5° S in b denotes the net volume transport from the Indo-Pacific to the Southern Ocean over the highlighted depth. The coloured circles highlight the meridional overturning circulation strength  at these locations. The term IndoPac_ResidualUp is calculated as a residual  by rearranging the equation shown below the panels. c,d, Schematic of the

AMOC’s upwelling pathways in the present day (c) and under scenarios of extreme GHG or North Atlantic freshwater forcing (d). Transport pathways are sketched, with increasing water mass density illustrated by a colour gradient  from yellow to dark green.

Our analysis reveals that SO wind-driven upwelling maintains a weakened AMOC under extreme forcing, overcoming the destabilizing effects of a developing Pacific Meridional Overturning Circulation (PMOC), with implications for understanding both past and future risks of AMOC collapse. We define the PMOC as a clockwise overturning cell in the Indo-Pacific Ocean (Methods), characterized by sinking and densification occurring in the subtropical North Pacific or more southerly latitudes, rather than the more commonly referenced northern latitudes.

Future fate of the AMOC

We have shown that SO wind-driven upwelling prevents an AMOC collapse under extreme climate forcing in CMIP6 climate models. The AMOC’s future strength depends not only on the future SO upper cell strength (which depends on its present-day strength and change) but also on the future PMOC strength (if it forms) (Fig. 4c,e; r = 0.90 (r = 0.98) for 4xCO2 (u03_hos), excluding anomalous models shaded in orange and purple). Previous studies have highlighted the role of SO wind-driven upwelling in sustaining an AMOC in simple models, but its importance in comprehensive global climate models under extreme forcing was unexplored. GHG forcing strengthens the SO westerly winds, strengthening the SO upper cell33. Thus, for an AMOC collapse or substantial AMOC weakening to occur, a strong PMOC that upwells in the SO (Fig. 1d) is essential because SO wind-driven upwelling must be balanced by downwelling in either the Atlantic or Indo-Pacific oceans to conserve volume.

An active PMOC associated with a weakened or collapsed AMOC was evident in past climates, including during the Last Glacial Maximum and its termination and the warm Pliocene when atmospheric CO2 levels were similar to present-day levels. Our findings suggest that PMOC formation may have facilitated AMOC collapses in past climates by reducing the SO upwelling of AMOC deep waters. The PMOC transports heat northwards, and affects ocean biogeochemistry and carbon uptake, highlighting the need to assess its impact on future climate in CMIP6 models.

Although SO upwelling sustains the AMOC under the extreme forcings considered here, increased forcings may further weaken the AMOC, but only if the SO upper cell weakens or the PMOC strengthens. AMOC weakening is therefore resisted through maintenance of the SO winds and freshwater input to the Indo-Pacific Ocean, implying that a large forcing is required for an AMOC collapse. Hence, we argue that changes in the hydrological cycle or changes in freshwater transport into the Indo-Pacific Ocean, in addition to the Atlantic Ocean, may be crucial for AMOC tipping by enabling formation of a strong PMOC. Although the models show a PMOC does not develop or remains generally weak in realistic future scenarios, if they underestimate the possibility of a strong PMOC forming, they may also underestimate the risk of a future AMOC collapse. Therefore, understanding model biases is essential.

The future extent of AMOC decline remains uncertain, despite its critical impact on heat, carbon and nutrient transport, and thus on global climate and ecosystems. We have shown that SO wind-driven upwelling prevents an AMOC collapse in CMIP6 climate models under extreme GHG and North Atlantic freshwater forcings. With predicted stronger SO winds and the present-day Bering Strait open, we conclude that a twenty-first century AMOC collapse (defined here as weakening to below 6 Sv) is unlikely. However, to refine AMOC projections, a greater focus on ocean circulation changes beyond the North Atlantic and their driving mechanisms is essential. Future changes in both the Atlantic and Pacific overturning would impact regional weather, climate, ecosystems and agriculture, so accurate projections of both are required to inform adaptation and resilience to climate change.