More New Science Undercuts the Hot and Chilly Narrative Around a Looming Atlantic Current Collapse

Stop running AMOC, but do still work hard to cut heat-trapping gases and community climate risk.

A study published this week in Nature, building on other recent research, shows the hollow nature of the much-hyped messaging around an impending shutdown of the Atlantic Ocean circulatory system for heat that helps temper Europe’s climate.

Here’s the core finding about the Atlantic Meridional Overturning Circulation (a k a AMOC):

[W]e show that the AMOC is resilient to extreme greenhouse gas and North Atlantic freshwater forcings across 34 climate models.

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.

The study, Continued Atlantic overturning circulation even under climate extremes, was done by researchers from Britain’s Met Office and the University of Exeter.

As I’ve warned for nearly two decades, hot narratives that fit existing frames (e.g., climate emergency) capture attention and headlines, but can hide what the broad body of climate science says and doesn’t say about current and future threats. Human-driven gobal warming is plenty serious enough to justify aggressive steps to cut heating emissions and societal vulnerability. Hashtag #realityisbadenough.

Here’s a summary posted on LinkedIn by the lead author, senior Met Office climate scientist Jon Baker:

Our new research challenges recent alarming predictions of an imminent collapse of the Atlantic overturning circulation (AMOC). We find that strong Southern Ocean winds keep this vital ocean “heat engine” running throughout this century in CMIP6 climate models, even under extreme climate change scenarios. Our findings suggest a catastrophic AMOC collapse before 2100 is unlikely – but the risks are real.

🌍 Why this matters:

🔹 A sudden “big freeze” in Europe probably isn’t imminent.

🔹 But the stakes remain high: Even an expected partial AMOC weakening could disrupt global rainfall patterns, alter ocean carbon storage, accelerate sea level rise along the US East coast, and disrupt marine ecosystems. Cutting greenhouse gas emissions is essential to reduce these risks and limit global warming.

🔹 New insights: The Pacific and Southern Ocean’s role in the AMOC’s decline is more important than previously recognised. This highlights the urgent need to improve observations and modelling of the Pacific and Southern Ocean circulations to refine AMOC projections. The impacts of potential changes in the Pacific circulation on marine ecosystems, ocean carbon storage and global weather needs further research.

📖 Read the full study: https://lnkd.in/e8dDEAg3

Thanks to my fantastic coauthors, Mike Bell, Laura Jackson, Geoff Vallis, Andy Watson, and Richard Wood for their invaluable contributions to this research.

There’s been prompt pushback on the valuable Realclimate blog from Stefan Rahmstorf, the German ocean and climate scientist who has been studying the overturning circulation for decades and, in recent years, has been a prominent campaigner for climate action based on the threat of an ocean current collapse and European chill.

Read his discussion of the study, which concludes with this trenchant line:

It does not change the assessment of the risk and impact of future AMOC changes in response to human-caused global warming.

If there were more time, I’d organize a Sustain What discussion with everyone. But I think it’s clear that this is an area of science you can basically chill out about - even as you don’t chill out about the need to stem warming and vulnerability to impacts.

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There was a bit of a hashout around the AMOC hosted by David Wallace-Wells of The New York Times last year, in which Rahmstorf and longtime climate scientist Michael Oppenheimer offered distinct views on the Atlantic Ocean current question. If you have time, watch it: Michael Oppenheimer and Stefan Rahmstorf | How Close is Climate to a Tipping Point? Oppenheimer noted that the actions that are needed don’t change no matter what the AMOC may do later in the century.

Also read this January Realclimate post by Rahmstorf, which cautioned against “media whiplash” - a syndrome I first warned about in 2008 in the New York Times - facing the herky-jerky flow of evolving science digging in on consequential questions.

Here’s a link and excerpt from my 2008 Times story: Climate Experts Tussle Over Details. Public Gets Whiplash.

When science is testing new ideas, the result is often a two-papers-forward-one-paper-back intellectual tussle among competing research teams.

When the work touches on issues that worry the public, affect the economy or polarize politics, the news media and advocates of all stripes dive in. Under nonstop scrutiny, conflicting findings can make news coverage veer from one extreme to another, resulting in a kind of journalistic whiplash for the public.

This has been true for decades in health coverage. But lately the phenomenon has been glaringly apparent on the global warming beat….

Scientists see persistent disputes as the normal stuttering journey toward improved understanding of how the world works. But many fear that the herky-jerky trajectory is distracting the public from the undisputed basics and blocking change. “One of the things that troubles me most is that the rapid-fire publication of unsettled results in highly visible venues creates the impression that the scientific community has no idea what’s going on,” said W. Tad Pfeffer, an expert on Greenland’s ice sheets at the University of Colorado.

“Each new paper negates or repudiates something emphatically asserted in a previous paper,” Dr. Pfeffer said. “The public is obviously picking up on this not as an evolution of objective scientific understanding but as a proliferation of contradictory opinions.”

Several experts on the media and risk said that one result could be public disengagement with the climate issue just as experts are saying ever more forcefully that sustained attention and action are needed to limit the worst risks.

Parting graphic from my #Watchwords series.