Paper: Weakening Atlantic overturning South Atlantic salinity pile-up

[donsutherland1]

A newly published paper revealed new evidence of a slowing of the Atlantic Meridional Overturning Circulation (AMOC) in response anthropogenic warming. The paper can found here.

[forkyfork]

here's a new paper on the subject: link

[LibertyBell]

16 hours ago, forkyfork said:

here's a new paper on the subject: link

weenies are cheering because they think this will result in colder and snowier winters

[etudiant]

21 hours ago, forkyfork said:

here's a new paper on the subject: link

As Mark Twain said: "That's the wonderful thing about science, you get such a wholesale return in conjecture on such a trifling investment of facts'.

[forkyfork]

i guess it's easier to cut and paste mark twain instead of reading the paper

[etudiant]

2 hours ago, forkyfork said:

i guess it's easier to cut and paste mark twain instead of read the paper

I actually did read the paper and was tempted but refrained from quoting HL Menken:  The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary.

I believe it to be quite apposite in this case, grant seeking researchers are no different from politicians, they make their case on the 'if it bleeds, it leads' principle.

[forkyfork]

you didn't read it

[etudiant]

1 hour ago, forkyfork said:

you didn't read it

Just the non paywalled section.   

The punch line:  These results reveal spatially consistent empirical evidence that, in the course of the last century, the AMOC may have evolved from relatively stable conditions to a point close to a critical transition.

Sounds like a plausible hobgoblin to me.

[LibertyBell]

6 hours ago, etudiant said:

Just the non paywalled section.   

The punch line:  These results reveal spatially consistent empirical evidence that, in the course of the last century, the AMOC may have evolved from relatively stable conditions to a point close to a critical transition.

Sounds like a plausible hobgoblin to me.

It makes sense because the flow of weather systems themselves have slowed down, and the prime evidence of that are these high precip total "bombs" we're getting on a regular basis.  And there is a verified feedback mechanism between the atmosphere and the oceans, so it would be logical to expect the ocean currents to slow down and weaken too.

[LibertyBell]

11 hours ago, forkyfork said:

i guess it's easier to cut and paste mark twain instead of read the paper

If there's going to be a paste, might as well paste from the summary of the paper itself

The Atlantic Meridional Overturning Circulation (AMOC), a major ocean current system transporting warm surface waters toward the northern Atlantic, has been suggested to exhibit two distinct modes of operation. A collapse from the currently attained strong to the weak mode would have severe impacts on the global climate system and further multi-stable Earth system components. Observations and recently suggested fingerprints of AMOC variability indicate a gradual weakening during the last decades, but estimates of the critical transition point remain uncertain. Here, a robust and general early-warning indicator for forthcoming critical transitions is introduced. Significant early-warning signals are found in eight independent AMOC indices, based on observational sea-surface temperature and salinity data from across the Atlantic Ocean basin. These results reveal spatially consistent empirical evidence that, in the course of the last century, the AMOC may have evolved from relatively stable conditions to a point close to a critical transition.

[LibertyBell]

conclusion is interesting

 

At a confidence level of 0.05, one would expect to obtain an apparently significant positive trend in only 1 out of 20 test realizations by chance, if there were in fact no underlying trend. Although higher numbers of significant EWS are obtained for the CMIP models, these findings still raise concern regarding whether state-of-the-art climate models would be skilful in predicting a forthcoming AMOC collapse. This is in agreement with previous results showing that the present AMOC mode is too stable in state-of-the-art models9, most likely due to an underestimation of the freshwater export from the northern Atlantic Ocean, caused by errors in the salinity fields and insufficient model resolution12. The high-resolution, eddy-permitting HadGEM3-GC2 model, which was used to establish the suitability of the SST-based AMOC indices employed here51, constitutes a major step forward concerning a more accurate representation of the AMOC and its stability12,14. A continuous evaluation of new model versions in terms of AMOC indices and their EWS will be subject to future research. In particular, for models with excessively stable AMOC, one would not expect to observe EWS, and the results presented here could therefore be used to identify observational constraints for climate models. In simulations with a coupled AOGCM with hosing-enforced AMOC collapse, EWS in terms of rising variance and AC1 have been revealed41. The evolution of the AC1 prior to AMOC collapse in the simulations of the latter study (see fig. 4c there) is very similar to the evolution of the AC1 of the observation-based indices investigated here (Figs. 3g,h and 4c and Extended Data Figs. 3g,h, 4g,h, 5g,h, 7g,h and 8g,h). The EWS revealed here for observation-based AMOC indices thus behave exactly like corresponding signals in comprehensive model simulations prior to an AMOC collapse. Note that, in the model hosing experiment41, the AMOC collapses even before the AC1 reaches the critical value AC1c = 1 (corresponding to λc = 0; Methods) because the fluctuations push the AMOC out of the weakly stable state already before it ceases to exist. Similar observations have been made also in more recent hosing experiments53. The results presented here hence show that the recently discovered AMOC decline during the last decades is not just a fluctuation related to low-frequency climate variability or a linear response to increasing temperatures. Rather, the presented findings suggest that this decline may be associated with an almost complete loss of stability of the AMOC over the course of the last century, and that the AMOC could be close to a critical transition to its weak circulation mode.

[LibertyBell]

7 hours ago, etudiant said:

Just the non paywalled section.   

The punch line:  These results reveal spatially consistent empirical evidence that, in the course of the last century, the AMOC may have evolved from relatively stable conditions to a point close to a critical transition.

Sounds like a plausible hobgoblin to me.

it's 8 pages and includes a bunch of graphs and maps, so it's plenty.

[etudiant]

4 hours ago, LibertyBell said:

it's 8 pages and includes a bunch of graphs and maps, so it's plenty.

Is there access outside of the paywall? I could not find it.

 

4 hours ago, LibertyBell said:

If there's going to be a paste, might as well paste from the summary of the paper itself

The Atlantic Meridional Overturning Circulation (AMOC), a major ocean current system transporting warm surface waters toward the northern Atlantic, has been suggested to exhibit two distinct modes of operation. A collapse from the currently attained strong to the weak mode would have severe impacts on the global climate system and further multi-stable Earth system components. Observations and recently suggested fingerprints of AMOC variability indicate a gradual weakening during the last decades, but estimates of the critical transition point remain uncertain. Here, a robust and general early-warning indicator for forthcoming critical transitions is introduced. Significant early-warning signals are found in eight independent AMOC indices, based on observational sea-surface temperature and salinity data from across the Atlantic Ocean basin. These results reveal spatially consistent empirical evidence that, in the course of the last century, the AMOC may have evolved from relatively stable conditions to a point close to a critical transition.

I did just that, quoting the last sentence of the summary, which you've helpfully added in full.

[LibertyBell]

2 hours ago, etudiant said:

Is there access outside of the paywall? I could not find it.

 

I did just that, quoting the last sentence of the summary, which you've helpfully added in full.

it's 8 pages here at the link Forky posted

https://www.nature.com/articles/s41558-021-01097-4.epdf?sharing_token=qWMQcnRcVRZQmZ_yahYbd9RgN0jAjWel9jnR3ZoTv0ODQw4Na6S4LwvIIwjZ_S3NdBoG6pi8c5NBfIwoUKp1VK_OHHszXMnB3OMoyz8L8emOhG-hoDsJyn1YMubz_IampYbIRg_8P9vjnfIPPzRQwm6m9BfwEGfoLu0JsB4E2trSfyu4r947mOz1oZQlyxQxZLxaMkEINR4Wt7XEIrPrRkahci-lKgCSTZahFzlH7wM%3D&tracking_referrer=www.washingtonpost.com

 

It says 21 pages, but after page 8 there's a long list of sources and other research listed, the actual paper is the first 8 pages of the PDF file.

Also, I just heard that there's new research coming out of the IPCC tomorrow that convincingly connects excessive wild fires to climate change.  I mean we all knew this is the case, but it's nice to have it in print.

 

[chubbs]

Per this study, AMOC collapse promotes La Nina.

https://phys.org/news/2022-06-huge-atlantic-ocean-current-downif.html

https://www.nature.com/articles/s41558-022-01380-y

[A-L-E-K]

hate it

[Vice-Regent]

On 6/9/2022 at 7:32 AM, A-L-E-K said:

hate it

It's eating my coastline bro. Getting sea level rises that are 30 years ahead of predictions because some aspects were not considered. Prior to 2000s it was not even known that sea level was lower on the windward side of ocean currents therefore creating the illusion that our coastlines are more resilient or stable than they are.