Critical Atlantic current significantly more likely to collapse than thought

[muriel_volestrangler]

Source: The Guardian

The critical Atlantic current system appears significantly more likely to collapse than previously thought after new research found that climate models predicting the biggest slowdown are the most realistic. Scientists called the new finding “very concerning” as a collapse would have catastrophic consequences for Europe, Africa and the Americas.

The Atlantic meridional overturning circulation (Amoc) is a major part of the global climate system and was already known to be at its weakest for 1,600 years as a result of the climate crisis. Scientists spotted warning signs of a tipping point in 2021 and know that the Amoc has collapsed in the Earth’s past.

Climate scientists use dozens of different computer models to assess the future climate. However, for the complex Amoc system, these produce widely varying results, ranging from some that indicate no further slowdown by 2100 to those suggesting a huge deceleration of about 65%, even when carbon emissions from fossil fuel burning are gradually cut to net zero.

The research combined real-world ocean observations with the models to determine the most reliable, and this hugely reduced the spread of uncertainty. They found an estimated slowdown of 42% to 58% in 2100, a level almost certain to end in collapse.

Read more: https://www.theguardian.com/environment/2026/apr/15/critical-atlantic-current-significantly-more-likely-to-collapse-than-thought

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The paper in Science Advances: https://www.science.org/doi/10.1126/sciadv.adx4298

Climate models show considerable discrepancies in their future projections around the Atlantic, mainly due to uncertainties in the fate of the Atlantic Meridional Overturning Circulation (AMOC). Climate models suggest a reduction in AMOC strength of 32 ± 37% by 2100 (90% probability, Shared Socioeconomic Pathways 2-4.5 scenario, Coupled Model Intercomparison Project Phase 6). To refine this estimate and reduce its uncertainty, we use four different observational constraint methods. The best one, which provides the lowest leave-one-out error, integrates a large set of observable variables using ridge-regularized linear regression—a method unusual in climate science. It gives an estimate of the AMOC slowdown of 51 ± 8% (90% probability), i.e., a weakening ∼ 60% stronger than suggested by the multimodel mean. This refinement mainly results from correcting a bias in South Atlantic surface salinity, consistent with recent studies emphasizing its role in the proximity to an AMOC tipping point. This more substantial AMOC weakening has key implications for future adaptation strategies.

The Guardian has comment from Prof Stefan Rahmstorf, at the Potsdam Institute for Climate Impact Research in Germany, who is a leading expert on AMOC, says "This is an important and very concerning result. It shows that the ‘pessimistic’ models, which show a strong weakening of the Amoc by 2100, are, unfortunately, the realistic ones, in that they agree better with observational data. ... I now am increasingly worried that we may well pass that Amoc shutdown tipping point, where it becomes inevitable, in the middle of this century, which is quite close. ... I argued [a collapse must be avoided at all costs] when we thought the chance of an Amoc shutdown was maybe 5%, and even then we were saying that risk is too high, given the massive impacts. Now it looks like it’s more than 50%. The most dramatic and drastic climate changes we see in the last 100,000 years of Earth history have been when the Amoc switched to a different state."

[FakeNoose]

1. We're already past the point of no return, folks

It's going to happen sooner rather than later, and it will be completely devastating to all life on earth.

[Boomerproud]

2. I wish I disagreed with you.

I really believe mankind in general has given up on even attempting to solve even the most solvable issues because of the reality of the situation.

[Cheezoholic]

3. Agree 100%. And when it comes to the oceans it's not just AMOC concerns. I think we've depleted fish

and other marine life to levels that may not recover or at least not fully recover for centuries, already also not just from treating the Oceans like they are endless producers of these but also from treating them as dumping ground no different than we did 500 years ago We've been crapping and pissing in them forever and have never learned.

It's a scary future our kids and grandkids. We can only try and help put the right people in the positions of power that can change the course and more importantly prepare for these eventualities.

[Javaman]

4. I wonder what happens to the oceans carbon sink when the AMOC goes? nt

[wolfie001]

5. I live in the mid-Atlantic and nor'easters are becoming quite rare

Not getting hardly any moisture from the ocean. Not many backdoor fronts with the fine and steady rain. Very dry. For the past 3 years or so? Not good.

[chowder66]

6. We are such a parasitic species. We are killing our host.