Recent research indicates the AMOC has been stable for the last 40-60 years, and paleo data takes that further back.
New modeling by Baker et al. shows that Atlantic circulation is hard to change. The researchers simulated a sudden 4x increase in carbon dioxide levels and let the models run for a century. They write that “it [the AMOC] does not collapse in the model experiments considered here.”
That depends on how you define stable. The paper says
a few global climate models suggest that the AMOC could collapse (that is, weaken to zero or reverse)
So they equate “collapse” with weaken to zero. The models show AMOC weakening, but no complete collapse. Would you say your income is stable if it drops in half but doesn’t go to zero?
The conclusion that there wasn’t a complete collapse in the past and there wont be one in the future isn’t really good news. Paleo data shows that AMOC changes in the past had large climate impacts. If future weakening is like past weakening, we can expect future climate impacts to also have large impacts. Good news would be a collapse in the past but not in the future. Unfortunately, that’s not what they’re saying.
The authors conclude
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.
Here’s their graph of model AMOC weakening. Each curve is a different climate model. None go to zero and the authors conclude there will be no complete collapse. Roughly, the models show AMOC weakening by about half.
Consensus is not proof. The scientific method tests hypothesis against reality. All consensus says is that many think the hypothesis is valid while few doubt it. That’s not proof. I love the way Richard Feynman started one of his lectures, “You start with a guess. All it is is a guess.”
Some parts of Europe might see temperatures plunge by up to 30 degrees Celsius over a century, the study finds,
“might see temperatures plunge” is not proof, it’s a hypothesis, a guess. This hypothesis suggests that global warming with rearrange temperatures, some higher, some lower.
Stefan Rahmstorf, a physical oceanographer at Potsdam University in Germany, who was not involved with the study, said it was “a major advance in AMOC stability science.”
I was thinking of the Volkov paper that came out in September:
Florida Current transport observations reveal four decades of steady state https://www.nature.com/articles/s41467-024-51879-5 The results of this study indicate that, if climate models are correct that the AMOC is slowing or will soon slow down, this slowdown has not yet been reflected in the FC [Florida Current] and the AMOC transports, or the observational records [since 1982] are still too short to detect it with confidence. This is in accord with other observation-based studies.
Absolutely. If you want proof go to math. The square root of 2 is irrational, prime numbers go on forever, the Pythagorean theorem. All rigorously proven.
Science is not math. Science gives evidence, not proof. If the evidence is strong you get consensus. There’s no proof that apples fall from trees, the Sun will rise tomorrow, microbes cause disease, smoking causes cancer, or humans are changing the climate. It’s all evidence and consensus.
