Physics-based early warning signal shows that AMOC is on tipping course
"One of the most prominent climate tipping elements is the Atlantic meridional overturning circulation (AMOC), which can potentially collapse because of the input of fresh water in the North Atlantic. Although AMOC collapses have been induced in complex global climate models by strong freshwater forcing, the processes of an AMOC tipping event have so far not been investigated. Here, we show results of the first tipping event in the Community Earth System Model, including the large climate impacts of the collapse. Using these results, we develop a physics-based and observable early warning signal of AMOC tipping: the minimum of the AMOC-induced freshwater transport at the southern boundary of the Atlantic. Reanalysis products indicate that the present-day AMOC is on route to tipping. The early warning signal is a useful alternative to classical statistical ones, which, when applied to our simulated tipping event, turn out to be sensitive to the analyzed time interval before tipping."
...
"AMOC collapse
To develop such an early warning indicator, we performed a targeted simulation to find an AMOC tipping event in the Community Earth System Model (CESM; version 1.0.5). This CESM version, which has been used in the Coupled Model Intercomparison Project (CMIP), phase 5, has horizontal resolutions of 1° for the ocean/sea ice and 2° for the atmosphere/land components (see Materials and Methods)."



https://www.science.org/doi/10.1126/sciadv.adk1189#body-ref-R2

So model based rather than physics based.
The tipping point is model year 1758 or 3782AD (or CE if you are so inclined).
I will let Willis Eschenbach continue, he does it so well.


"Now if you follow my work, you’ll know that I often ask the most impertinent questions. So I got to thinking about something they didn’t mention in their study … just how much modeled fresh water have they added?"

"Now, a Sverdrup is a million cubic meters per second. So over the 1,758 model years from the start up to the tipping point, they’ve added a total of:

0.264 Sv * 106 cubic meters per second/Sv * 1758 years * 31,556,926 seconds per year / 109 cubic meters per cubic kilometer =

14,629,305 cubic kilometers of modeled fresh water added.

Now, fourteen million cubic kilometers of water, that’s a very big number. So let’s compare it to something that’s also very big … say the total volume of water in the entire Greenland Ice Cap. Here’s that comparison."



https://wattsupwiththat.com/2024/02/11/tipping-is-optional/

So that's all the Greenland ice sheet and half the Antarctic ice sheet.

I've known about that for over 30 years -

it's the famous collapse of the Gulf stream
which would plunge Europe into an ice age.

Jasin wrote on Feb 12^th, 2024 at 5:42pm:



A lot of Europe is at a similar latitude to Canada so it
would get much colder without the Gulf steam.

Jasin wrote on Feb 12^th, 2024 at 5:50pm:



The Panama and Suez represent a drop in the oceans.