4 Likes
Iām not a climate scientist, butā¦
The cycle that drives the Gulf Stream takes decades to go from beginning at the arctic to N. Europe at the tail end. We would know if the North Atlantic Bottom Current has stopped already.
9 Likes
Could you flesh that out a bit? Iām not following, and Iād like to understand better.
5 Likes
Sure. The currents of the North Atlantic are a big conveyor belt. You could start following the conveyor belt at any point, really, but the āengineā as such is the North Atlantic Bottom Current. The NABC is caused when saltwater reaches the deep arctic, gets really, really cold and very salty as ice precipitates out of the saltwater. That water is very dense and drops fast to the bottom, which is a south-facing slope. The momentum causes a strong current of salty, cold water south along the bottom of the ocean. Eventually, that current pushes up against the slope of the coasts while warming and diluting, and becomes warm surface currents near the equator. Those currents flow north and replenish the water that forms the NABC. One of the warm currents is the Gulf Stream, that runs northwest from ~ The Bahamas towards the British Isles and Northern Europe. The effect of the Gulf Stream is to warm N. Europe to a much higher temperature than it would be without. If the Gulf Stream collapses, N. Europe is going to get much colder.
10 Likes
Thanks! I got that part, but then you said:
We would know if the North Atlantic Bottom Current has stopped already.
But it seems to me there might be a delay in us realizing how bad it is because of the time factor in getting it to the surface edges. Itās not the Gulf Stream.
5 Likes
7 Likes
Hopefully they wonāt be launched on a Musk rocket.
3 Likes
Speaking of Musk ie Teslaā¦
Reliable Robotics, a Silicon Valley startup aiming to automate conventional fixed-wing planes, has received approval from the Federal Aviation Administration to proceed with its plan to test and certify fully automated aircraft systems
āWe want to be on multiple aircraft frames (and) sell into multiple markets,ā including cargo and military applications, said Rose, a former executive with Tesla(TSLA.O) and SpaceX.
Againā¦
4 Likes
Definitely. I know scientists monitor the deep ocean currents directly with sensors, so they would know if there were issues there (which there are, but not āimminent collapseā issues). And it looks like the understanding of world ocean currents has improved since my oceanography class in college [mumblemumble] years ago! Itās more complex than what I had learned.
The instability of the driver for the ocean conveyor belt is a big concern. But the articles Iāve seen on it say this prediction of collapse of the Gulf Stream is based on modeling, not on direct measurements. The direct measurements are holding (for now). But whether the collapse happens in 2025 (which is highly unlikely, out at the edge of the predictive model) or a century from now, it is still something that should be lighting a fire under policy makers to address climate change.
13 Likes
12 Likes
All the same system, isnāt it? Like a conveyor belt? The top and the bottom move at the same speed?
Thereās nowhere to put the extra water if part of it stops ā it all moves together, or it all stops at once
2 Likes
Itās not all a single loop though. Like for instance if something below stops, well, there are other directions for the water to circulate on the surface.
Honestly I had kind of thought that was the origin of the Gulf Stream, the North Atlantic gyre, although it definitely forms part of the thermohaline circulation driven by the ice caps too. 
5 Likes
Yes, it is at the edge of the scatter-plot. Or whatever data viz is being used here.
Amazingly (in a bad way), lots of climate breakdown events are happening āsooner than we thoughtā and sooner than models have led us to believe. So yeah I am tracking these edge cases and Black Swan events because dammit they suck when they do happen and they seem (ok ok confirmation bias here maybe) to be escalating in frequency and duration.
Agreed.
The Intergovernmental Panel on Climate Change (IPCC) says a full AMOC collapse is unlikely in the current century, based on climate modelling.
In their new study, siblings Peter and Susanne Ditlevsen, both at the University of Copenhagen, Denmark, used sea surface temperature data from the sub-polar North Atlantic ā which dates back to 1870 ā as a proxy for the stability of the AMOC.
Btw, 10 points awarded for Atlantic Meridional Overturning Circulation getting the acronym AMOC (which is soooo close to AMOKā¦). O the gods do love irony.
Need something to nerd out to, fundamentally? Hereās the IPCC report:
https://www.ipcc.ch/srocc/chapter/chapter-6/
Iāll download the PDF of it for later. It certainly looks thorough, at my first glimpse 'n gallop.
@chgoliz
A simplified fact-based explainer by reputable humans, and not crafted by twitchy hyped up doomer-preppers, here:
A more general overview re ocean currents (not just the Gulf Stream)ā¦ a TEDx so it canāt be entirely fact-free:
ETA:
typo
11 Likes
4 Likes
Oh hey, Beau did a thing yesterday on the Atlantic Meridional Overturning Circulation.
He does clarify a few things and he also mentions that movie (which I have not seen).
7 Likes
And scientists (well, geeks in general) love a good backronym. 
Written a few myself. Had a trader up in arms when I suggested the software I was writing for him be named āVolatility Model Investigation Toolā (VoMIT).
11 Likes
Regarding
The Nature paper is an interesting one, I gave it a first read through, and Iāll see if I can summarize.
The authors start with a bunch of simulations that were done for the IPCC which used first principles, the basic math models of how water moves in the ocean, and Very Big Computers. Each of these āfirst principlesā studies point to a collapse of AMOC: enough fresh water pours off Greenland and out of the Arctic and it stops, fairly abruptly. They disagree fairly widely, however, about how much fresh water is āenoughā (just like you get slightly different weather forecasts depending on who computes them).
When the IPCC originally analyzed the āfirst principlesā results, they fit an average and looked at the variation. It was fairly simple, but didnāt capture much information.
The new paper uses the same āfirst principlesā models, and summarizes those using the idea that there really is a tipping point. They use a standard equation for tipping points in a noisy environment (think: things falling over around stampeding toddlers); itās a fairly simple, one line equation, but it captures a little bit more action. The new paper fits the āfirst principlesā simulations to this equation, and maps it to the available observations of the AMOC.
The result is better statistics that teases out what the āfirst principlesā models might be saying. The new paper shows a driving process with a tipping point is justified by the observations and the models, then shows that the original IPCC calculations are telling us more than was initially realized.
That āmoreā is a tighter, sooner estimate of when the tip might occur.
My initial searches for RAPID-MOC brought up programs that had finished a few years ago 
but the sensor network continues to operate.
The latest data appears to be from 2020. They have a Twitter X account.
7 Likes
Sharks being cool and all isnāt getting me in Cape waters anytime soon!
Ohh hellz no!
4 Likes
3 Likes
6 Likes
