My thanks to Jaime Jessop for returning my attention to the subject of this piece, and my apologies to her for going over ground that she has already covered so well.

I first became aware of the return of the Atlantic Meridional Overturning Circulation (AMOC) scare story a few weeks ago when the You Tube algorithm pushed a Sabine Hossfelder video at me. In this she sought to worry viewers about the possibility of temperatures in north west Europe dropping by 5C or even 10C should AMOC shut down.

Around the same time the BBC website published an article with the heading “Could the UK actually get colder with global warming?” That in turn followed hard on the heels of another BBC article which appeared just a few weeks before that, headed “The ocean current vital to regulating our weather”. It’s almost as though the earlier article was setting the scene for the second article, and softening the public up for it.

It’s all rather odd, since it’s seven years or so since a study by Caesar, Rahmstorf, Robinson, Feulner and Saba put the cat among the pigeons. It was titled “Observed fingerprint of a weakening Atlantic Ocean overturning circulation” and it offered evidence of a weakening of AMOC by around 15% since the mid twentieth century. Why, seven or so years later, is the possibility of an AMOC shutdown suddenly once more in the news? This is where it gets even stranger. The renewed interest and claims seem to have been triggered by a study by Terhaar, Vogt and Foukal, which appeared in Nature on 15^th January 2025, yet the study headline (“Atlantic overturning inferred from air-sea heat fluxes indicates no decline since the 1960s”) ought on the face of it to defuse, rather than ignite, AMOC scare stories. The core conclusion from the abstract was as follows:

Based on the here identified relationship and observation-based estimates of the past air-sea heat flux in the North Atlantic from reanalysis products, the decadal averaged AMOC at 26.5°N has not weakened from 1963 to 2017 although substantial variability exists at all latitudes.

One might have expected that the BBC article that followed the publication of last month’s study (and to my mind might have been triggered by it), should have talked about its results, and offered a cautious degree of optimism for its readers on the back of the study’s results. Not a bit of it. Instead we were presented with a scare story, which ignored the study altogether, and appeared to cite the results of the 2017 study instead (while not actually referring to the study or its date of publication). The BBC chose to offer us this partial (and not terribly up-to-date) analysis:

But Amoc appears to be getting weaker...

…indirect evidence suggests it could have already slowed by around 15% over the last couple of centuries, although not all scientists agree.

A slowdown in Amoc – meaning less warmer water would be transported to this region – is seen as a possible culprit.

This is “a very clear signature and footprint of a classic Amoc slowdown” says Matthew England, professor of oceanography at the University of New South Wales….

…In 2021, the IPCC said it had “medium confidence” that Amoc would not collapse abruptly this century, although it expected it to weaken.

But some more recent studies have pointed to a growing possibility of Amoc passing a tipping point in the coming decades, beyond which full collapse would be inevitable….

…But many scientists are growing increasingly concerned. Prof Thornalley argues that, whatever the imperfections of individual studies, taken together they “lead to a conclusion that we maybe need to be worried”….

The BBC would no doubt argue that it has presented a report about AMOC which contains a number of appropriate scientific caveats, and that it can’t be criticised for it. Yet, the report is undoubtedly on the alarmist side of things, and a fully balanced report would have included the results of the most recent study. It didn’t, and I find that inexcusable. BBC Science editors will surely be aware of it (it was all over the internet in the few days after its publication) and failure to mention it seems like an unacceptable oversight.

I am still mystified as to why they have suddenly decided to scare us with the prospect of freezing instead of boiling. Is it because although we are bombarded almost daily with stories of a heating world, we in the UK have seen precious little sign of warmer weather over the last few years? Did they need to suggest that January 2025 in the UK, being 0.9C cooler than the long-term average, ushered in a new and scarier climate? Is it because in 2024 Iceland experienced its coldest year since 1998? Is it because in January 2024 Oslo experienced the coldest temperature ever recorded there? Or is it just because we have to be kept in a constant state of fear about climate change?