You mean I should copy and paste the wrong information like you do?
The new study is interesting and solid science. We know the AMOC did shutdown at the end of the last ice age and the shutdown had major climate impacts. AMOC shutdown is a climate tipping point and if it does happen it will be bad.
We’ve only had direct measurements of AMOC since 2004 when an array of moored instruments was spread across the Atlantic at 26ºN. This is too recent to conclude whether or not the AMOC is slowing from direct measurements.
Most of the more sensational papers use indirect evidence of the AMOC strength. Some studies indicate the AMOC is slowing, others say maybe not. The new paper falls on the side of the AMOC isn’t slowing.
One thing to note about this new study is it is based on climate models. They make synthetic measurements in climate models of the same indirect evidence used by others to infer the AMOC is slowing. They then ask if the indirect evidences is actually correlated with model AMOC strength and find the answer is no.
On the other hand, these same climate models do show the AMOC slowing by about 40% over the 21st century, regardless of the validity of the indirect evidence.
Here is a graph from the IPCC from 2019 showing AMOC slowing vs. warming. There’s lot’s of uncertainty. The 40% slowing the models project is not close to the collapse threshold in the figure, and the IPCC projects the AMOC will not collapse in the 21st century.
It’s interesting that some of the people here and across the internet who are most dismissive of climate models when they don’t like what models say, happily support them when they do like what models say.
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I agree in plain language.
It is nothing as a study in plain language.
It depends on the rate at which we heat the planet. The developing world is coming on line with more cars etc…AI is adding to the electricity demand. The developed world is making some progress but the US is not making enough progress in eliminating greenhouse gasses.
Those who use things it is par for the course. It truly does not matter to them. They don’t care. But they are angry enough to argue about it.
It is anger to get on here with half baked information and go on and on.
The models are like throwing in a diagram. They mean only so much. The take away we need to slow our production of green house gasses.
A capitalist can make money making rope and hiring a lawyer to avoid the execution.
We have in situ measurements going back to 1982 which is what the September Volkov paper was correcting:
“A unique, sustained observing system in the Florida Straits, consisting of voltage measurements recorded from a submarine telecommunication cable installed between Florida and Grand Bahama Island, paired with regular ship surveys in the Florida Straits at 27°N, was established in 1982.”
Spinning, as you know from our time on the Climate Change board I am not a big fan of models. (“All models are wrong.”) I present them for those who have more faith in them.
DB2
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I was thinking if I wanted to be more gracious, I would dismiss them all as well. By nature they are misinformation.
We need to produce less greenhouse gas.
Frankly I don’t think you understand what models are. The AMOC is complicated. We don’t fully understand it. But it is important so we have to find some way to estimate what might happen to the AMOC. So we make imperfect models with each using different assumptions that give different perspectives of how the AMOC works. We ask these models to project the AMOCs future and we look to see where the models say we should test to see if the projections are happening.
These tests are hard to do and need to measured over decades. What you have then is a lot of uncertainty and knowledge gaps. Some tests show a slowing AMOC. Some do not. The only way to get a sense of what might be happening is to look at the totality of results, not just one or two.
The majority of those who have and continue to look at the totality of the data are disturbed and concerned. So concerned that a large group of climate scientists sent a letter to the Nordic Council of Ministers:
> We, the undersigned, are scientists working in the field of climate research and feel it is urgent to draw the attention of the Nordic Council of Ministers to the serious risk of a major ocean circulation change in the Atlantic. A string of scientific studies in the past few years suggests that this risk has so far been greatly underestimated. Such an ocean circulation change would have devastating and irreversible impacts especially for Nordic countries, but also for other parts of the world.. https://en.vedur.is/media/ads_in_header/AMOC-letter_Final.pdf
But what is keeping scientists up at night is something more tangible than models. It is the “Cold Blob”. The AMOC moves warm water from the Southern Hemisphere into a particular area in the Arctic. Several models project that if the AMOC slows, the temperature in this area will decline.
The Cold Blob (the large blue patch) is one of the only areas in the world showing a declining temperature since 1900. It is located right where the AMOC dumps warm water into the Arctic.
Specifically, out of 32 climate models, 11 accurately simulated the Cold Blob in the observed location. Four gave a slowing AMOC as the cause. Four others identified changes in heat radiation unrelated to current. The remaining three showed a combination of the two. Disagreement on the North Atlantic Cold Blob Formation Mechanisms among Climate Models in: Journal of Climate Volume 37 Issue 16 (2024)
Certainly not conclusive evidence for a slowing AMOC. Seems pretty concerning to me though given the likely consequences of an AMOC collapse.
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Forecasts matter but should not be believed.
Our problem is with rising temperatures. The takeaway we are at risk.
The scientific debate continues with a new study.
“The idea of a universal early warning sign for climate tipping points is very appealing,” says Clark Zimmerman, lead author of the new study and graduate student at the UW–Madison Department of Atmospheric and Oceanic Sciences (AOS). “However, you have to be careful when you apply a statistical technique that assumes a simple dynamical structure to a system as complex as the AMOC.”
Elizabeth Maroon, also a co-author and UW–Madison AOS professor concludes, “The climate is changing rapidly, and the AMOC will be impacted. Our study, however, is arguing that we should be cautious about jumping to conclusions regarding the AMOC’s future trajectory, as tempting as that may be.”
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Thanks for the article, spinning. Toward the end of the paper the authors "compare AMOC stability in two climate states: “pre-industrial” (1 × CO2) and “global warming” (2 × CO2). In the global warming scenario the ΔH space contains a larger monostable regime than the pre-industrial scenario…
This suggests that in a warmer background climate, the AMOC’s steady state may be more stable and less likely to feature a critical transition under hosing than in a colder climate.
Slowed Response of Atlantic Meridional Overturning Circulation Not a Robust Signal of Collapse
Zimmerman et al.
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL112415
DB2
You are determined to muddy the waters.
I doubt anyone is buying it.
I didn’t muddy the waters. I just read the paper all the way to the end.
Do you not like positive news?
DB2
I am not that into fiction.
AMOC is complicated and perilous and we do not know what will happen. That is the MAIN GCC risk — we are messing around with an extremely complicated set of intertangled systems upon which we depend for survival, it is the nature of complicated stuff to be unpredictable, and that is dangerous for humans with our huge demands on the biosphere.
AMOC going weird at some possible point is (using old North American Aviation parlance mangled and made famous by Rumsfeld) a “known unknown” of GCC. There are almost certainly a bunch of unknown unknowns that (duh!) we do not know about that could wipe us out.
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Does it bother you that hard coral cover of the Great Barrier Reef is at the highest since monitoring began 38 years ago?
DB2
No, thank you for asking.
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You’re welcome, ML. Leap seems to have trouble accepting information he disagrees with, but I suppose that’s not uncommon.
DB2
It was not information. It was biased speculation.
Well, there you go again.
Upthread bt referenced a paper that said that a signal (reduced variability) was a sign of impending AMOC collapse. Later, spinning presented research that showed that signal didn’t really show that. In fact, a warmer ocean was less likely to collapse (‘feature a critical transition’).
Science is messy, but saying it is not information is not correct.
DB2
Bull
And the Reagan quote means you ducked reality.
Not sure why I come into this. I had two posts on this thread and neither were about a tipping point.
Now in different thread I did bring up the van Westen paper that developed a new metric for identifying a tipping point and indicated that we were on track for an AMOC collapse based on that metric. https://www.science.org/doi/10.1126/sciadv.adk1189
The link from Spinning does not apply to the van Westen paper. I won’t go into the technical weeds but will note a statement made in the conclusion of Spinning’s link.
Our results show that in an idealized AMOC model CSD cannot readily distinguish between bistable and monostable regimes. It is therefore not obvious how CSD indicators could be used to reliably predict the approach of a critical transition in this case, even when the necessary time series conditions are met…On the other hand, in models, the sensitivity to model complexity, parameterization, and biases present additional challenges to the use of CSD. Aside from better constraining models, there is a need for strategies that can be applied to observational time series without a priori knowledge of the system dynamics. One option is to consider system-specific physically-based indicators (e.g., van Westen et al., [2024]…
In short, the van Westen et al (2024) tipping point conclusion is based on an analysis methodology that is not critiqued by Spinning’s link.
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