Another team asked whether #AMOC collapse is at all possible in #IPCC #climate models bc those models are apparently known to have strong bias toward keeping a stable AMOC. (I can relate😁 )
The team ran an experiment in which they took a pre-industrial Earth without climate change,
and every model year added a little bit more freshwater to it. This was just to prove that even those unrealistically stable model types can produce a tipped and collapsed AMOC with a certain AMOUNT of freshwater. (As opposed to making AMOC tipsy by the speed of adding smaller amounts of freshwater. See above post.)

#vanWesten etal 2024 "Physics-based early warning signal shows that AMOC is on tipping course"
https://www.science.org/doi/abs/10.1126/sciadv.adk1189
The paper also describes in vivid colour the impacts a tipped AMOC has (in a pre-industrial world). Immediately. Even tho the time from tipping to collapse or OFF might be 100 years: dramatic changes all over the world start from the first decade of a tipped system.

Have a look at all the diagrams and maps in the paper and in the supplement to feed your nightmares with gory details.

In a bi-monthly rhythm, this team of 4 scientists feeds us more details on their findings.

In this preprint, they project the tipping schedule: "The collapse time is estimated between 2037-2064 (10-90% CI) with a mean of 2050 and the probability of an AMOC collapse before the year 2050 is estimated to be 59 +/- 17%." https://arxiv.org/abs/2406.11738 #Smolders 2024 "Probability Estimates of a 21st Century AMOC Collapse"

Don't confuse it with #Ditlevsen 2023 who also put that year in our calendar, but arriving at it using a different method .

I don't know what they mean with "collapse". Do they mean the moment of tipping, the period of unstoppable slowdown? Or the actual off-state, the collapsED AMOC?

Anyway. What the study also looks at are locations of Early Warning Signals, EWS. And unfortunately, the 2 regions where "we" are actively monitoring the AMOC strength are not early-warning-regions at all. Nor is the Cold Blob.
Bummer. (The installations are called RAPID and OSNAP if you want to look them up.)

Where we should have set up monitoring installations 20 years ago was near South Africa's coast in a depth of 500m, where salinity transport changes before tipping occurs 4000km further North...

I do recall reading just this in their already published paper, too. Latitude 34°S is where all the action is, according to the team in Utrecht, Netherlands.

In the next post I'll show a heatmap of salinity at 32 to 36°S in depths of 150 to 700m. Brace yourselves...