Mastodawn

Mawbey et al 2026
https://www.nature.com/articles/s41467-026-68949-5
say that #WAIS retreat during the last deglaciation followed warmer seawater and not a warming air temperature.
On an unrelated matter, parts of their figure 3 caught my eye.
Especially the "ACR", Antarctic cold reversal pencilled in where it is.
For air temperature on the ice at WAIS, this cooling ACR began in 14.2ky BP (before present= before 1950).
But at that time, sea surface temperature had already cooled for 600 years or so.

Why did it catch my attention? Because this timing coincides nicely with the 2 locations I picked and plotted from Peltier's ice model https://www.atmosp.physics.utoronto.ca/~peltier/data.php

To investigate my idea of AMOC having two arms which do not stop at the same time, I picked a location in East Canada, Ungave Bay, and #Scotland on the other side of the #Atlantic.
What I found was indeed: East Canada experienced the cooling from the halted AMOC first and it took Scotland 1 time step longer to start regrowing its ice shield, suggesting that the Eastern arm of the #AMOC continued for quite a while longer when the Western arm had already stopped.

Timing:
14.8 ky
Sea surface temperature drops in Amundsen Sea
14.5 ky
Ungave Bay 🇨🇦 refreezes
14.2 ky WAIS air temperature drops
14 ky Scotland refreezes.

With the exception of WAIS air °C, the time resolution isn't definitive enough to answer this question – but it is an intriguing one:
what really came first? The warming of the Antarctic (lower ocean level) waters? Or the AMOC stop in its Eastern arm? 🐓 🥚
Antarctic circumpolar current is part of the AMOC – or vice versa. Antarctic bottom water formation is part of the AMOC. And they influence each other. So...

#paleoclimate #ocean #ice #climatechange

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gary Dec 2

@juliusgoat.bsky.social hey you can't take it like that! #wais

Wolfgang Stief Jun 3, 2025

Some of you probably remember WAIS. An Internet search engine from the Gopher era (more specific: a search protocol). TIL: Thinking Machines (those with the massive red blinkenlights servers) were the main driver and developer of WAIS: https://en.wikipedia.org/wiki/Wide_area_information_server #vintagecomputing #techhistory #wais #thinkingmachines #connectionmachine

Wide area information server - Wikipedia

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Tim Chase Jan 20, 2025

@nixCraft

Efficiency & accessibility.

You'd anonymously visit a site (whether web, #Gopher, #WAIS, FTP), get just the raw content and could read it perfectly fine over a 1200 baud dial-up modem on a 286 running DOS.

Nowadays you need a web-browser that consumes GB of RAM when idle, a multi-core CPU clocked at GHz speeds, connected via an always-on 5G or fiber connection, and you get umptybajillion privacy-invading adverts and auto-playing videos in the process distracting you from the content you're trying to obtain.

Is it prettier? Maybe

Is it better? Hardly

Julius Garbe Aug 22, 2024

Thwaites Glacier won’t collapse like dominoes as feared, study finds, but that doesn’t mean the ‘Doomsday Glacier’ is stable
https://theconversation.com/thwaites-glacier-wont-collapse-like-dominoes-as-feared-study-finds-but-that-doesnt-mean-the-doomsday-glacier-is-stable-236480 via @TheConversationClimate

#Antarctica #Ice #SeaLevel #Thwaites #DoomsdayGlacier #AntarcticIceSheet #WAIS 🇦🇶🧊🌊

Thwaites Glacier won’t collapse like dominoes as feared, study finds, but that doesn’t mean the ‘Doomsday Glacier’ is stable

Antarctica’s riskiest glacier is a disaster in slow motion, a polar scientist writes. But in a rare bit of good news, the worst-case scenario may be off the table.

The Conversation

anlomedad Jul 29, 2024

" Also, we find that rate-induced effects tend to allow a stabilization of the #AMOC in cases where the peak of the West Antarctica Ice Sheet meltwater flux occurs before the peak of the Greenland Ice Sheet meltwater flux."

Ah great. So we should pray for the #WAIS reaching its tipping point before #Greenland 's ice shield melts down to its point of no return? 😁
https://esd.copernicus.org/articles/15/859/2024/esd-15-859-2024.html Sacha #Sinet et al, 2024

It's not what they mean, I know. What I actually wanted to highlight is the circumstance that AMOC is also sensitive to the rate or speed in which freshwater is added, not only to the final amount of it. And this was also found in their study.

I first came across it in a 2021 paper by #Lohmann #Ditlevsen "Abrupt climate change as a rate-dependent cascading tipping point" https://esd.copernicus.org/articles/12/819/2021/esd-12-819-2021.html ,
Peter Ditlevsen being the brother in the sibling duo who in 2023 found a cool way to analyse noisy data in search for impending tipping behaviour and said, AMOC tips 2025-2097.

AMOC stability amid tipping ice sheets: the crucial role of rate and noise

Abstract. The Atlantic Meridional Overturning Circulation (AMOC) has recently been categorized as a core tipping element as, under climate change, it is believed to be prone to critical transition implying drastic consequences on a planetary scale. Moreover, the AMOC is strongly coupled to polar ice sheets via meltwater fluxes. On the one hand, most studies agree on the fact that a collapse of the Greenland Ice Sheet would result in a weakening of AMOC. On the other hand, the consequences of a collapse of the West Antarctica Ice Sheet are less well understood. However, some studies suggest that meltwater originating from the Southern Hemisphere is able to stabilize the AMOC. Using a conceptual model of the AMOC and a minimal parameterization of ice sheet collapse, we investigate the origin and relevance of this stabilization effect in both the deterministic and stochastic cases. While a substantial stabilization is found in both cases, we find that rate- and noise-induced effects have substantial impact on the AMOC stability, as those imply that leaving the AMOC bistable regime is neither necessary nor sufficient for the AMOC to tip. Also, we find that rate-induced effects tend to allow a stabilization of the AMOC in cases where the peak of the West Antarctica Ice Sheet meltwater flux occurs before the peak of the Greenland Ice Sheet meltwater flux.

Susanne Mullis-Pum Dec 24, 2023

„A study of octopus DNA may have solved an enduring mystery about when the rapidly melting West Antarctic ice sheet #WAIS last collapsed, unlocking valuable information about how much future sea levels may rise in a warming climate.“

https://www.cnn.com/2023/12/21/world/octopus-dna-west-antarctic-ice-sheet-climate-scn/index.html

anlomedad Dec 23, 2023

Kurioses.
1) An einer Sprache das #Klima erkennen, aus dem sie ursprünglich kam? Geht. Man zählt Konsonanten und Vokale in Wörtern und bei den Konsonanten guckt man nach Sonorität vs Zisch- und Kehllaute. Je mehr Zisch desto kalt. Nicht intuitiv, was? Liegt am Kehlkopf und an °C der Luft als Übertragungsmedium, sagen die Forscher bei Wichmann et al und
https://www.br.de/radio/bayern2/sendungen/sozusagen/je-waermer-desto-lauter-wie-das-klima-die-sprache-beeinflusst-100.html Nur 9min, viel zu kurz! Wichmann meint, Azteken könnten ihre Sprache mit den vielen X T K-Lauten von Migranten aus dem kühlen Norden gehabt haben. https://academic.oup.com/pnasnexus/article/2/12/pgad384/7457938?login=false und https://www.nature.com/articles/s41599-023-01969-4
Die Leute in der Kalahari kommen dann wohl auch aus Grönland ^^
2) Am Genom von antarktischen Oktopussen erkennen, ob #WAIS in den Warmzeiten vor 1.1mio Jahren, vor 420tsd Jahren und vor 120tausend Jahren kollabierte, als es +0.5-1.5°C ggü vorindustriell war?
War WAIS weg, konnten die Populationen aus der atlantischen #WedellSea und der pazifischen #RossSea hin und her sexeln. Sonst kein vielarmiger inter-population Sex.
https://www.science.org/doi/10.1126/science.ade0664 € preprint: https://www.biorxiv.org/content/10.1101/2023.01.29.525778v1.full

Sozusagen: Je wärmer, desto lauter: Wie das Klima die Sprache beeinflusst | BR.de

Natur bestimmt Kultur? Klima und Sprache hängen zusammen, behauptet der Linguist Søren Wichmann, der an der Universität in Kiel forscht. In einer neuen Studie hat er gezeigt, dass Sprachen umso "sonorer" werden, je näher man dem Äquator kommt. Was das genau meint und wieso das so ist, erklärt er im Interview.