2/
That the two AMOC branches collapse at different times can be seen in this image.
The lines in the chart are a few proxy time series in 100 year resolution from 90ka to 300 years ago. The background shapes are Milancovic cycles.
#AMOC stopped and restarted multiple times, best seen in the white line which is a proxy for local Greenland temperature.
About 14.5ka, 14.5 on the x-axis, #Greenland temperature stops its upward race and drops very quickly. I think, this is the convection collapse in the Subpolar Gyre they talk about in the video.
It's when, from top to bottom in the chart: the bright red Andes Glacier index halts its downward slope and plateaus for the whole period of the collapsing and restarting AMOC;
the tentative Sahara greening is halted, blue line;
while noticeably, the dark red Asian monsoon and the pink CH4 methane line still increase.
These two only crash when Greenland feels the last dramatic, rapid temperature drop.
This last bottoming out takes 100 years, and lasts for 1200 years, from 12.8ka to 11.6ka.
Then it takes less than 100 years for temperature, methane and monsoon to climb back up to previous levels.
The bright red tropical Andes Glacier Index and the blue Sahara proxy stay unfazed throughout. But in the aftermath of all this atmospheric re-arranging, the Sahara proxy suddenly flickers, then it tipps – into a lush green Sahara!
(So when the blue line drops, it means that it rains a lot in the Sahara.)
On the side:
4,200 years ago, something called the 4.2ky event happens. The Sahara flickers. The red Glacier Index records a regrowth.
And from 2.9ka, the Sahara tipps. And dries out rapidly. And the glacier has another short, larger growth period.
The Asian monsoon also experienced a hickup 4,200 years ago.
Maybe that was a global event. Maybe. Although methane did not flicker – but this might an artefact of low time step resolution.
Anyway. That's how the last AMOC collapse went. In an Earth System that was crawling out of the last ice age.
It collapsed in 2 stages, first the Subpolar Gyre and Labrador Sea convection stopped. And much later, the European branch stopped too.
Again: In an Earth System that was crawling out of the last ice age. So not to be taken as blueprint for what we're setting into motion this time round.
#PaleoClimate #ClimateChange
This week I am visiting the IBS Center for Climate Physics at Pusan National University in Busan, South Korea. I decided to add the paleo sea level data from Busan to GAPSLIP for the occasion. It is one of the nicest Holocene sea level curves in the world!
The modelled sea level from my ice sheet reconstruction does not work so well here in the Middle Holocene, which might be because there are sediment loading impacts at play, which I don't account for.
I worked with a great team of collaborators to produce a uniquely long #paleoclimate record from #caves in northern #utah. We dated stalagmites to show that mountain #permafrost repeatedly expanded during glacial periods and disappeared during interglacials in sync with orbital climate cycles over the past ~600,000 years. These results provide rare long-term constraints on alpine permafrost sensitivity and help place modern permafost thaw into a deeper climatic context. The paper was published in Quaternary Research; if you do not have access and wish to get a copy, feel free to send me a private request.
https://doi.org/10.1017/qua.2026.10076
#geology #climate #cave #caves #mountain #mountains #quaternary
New 46000-year record of the southern margin of the Indo-Australian Summer Monsoon just dropped from deadset legend Teresa Dixon at UQ.
#AusQuaternary #Monsoon #paleoclimate
https://www.sciencedirect.com/science/article/pii/S0031018226001410?via%3Dihub
Toll!
7.2mio Jahre alter Oberschenkel einer "Frau" wurde in Bulgarien gefunden. Der Oberschenkelhals und die Ansätze von schweren Gesäßmuskeln lassen auf den aufrechten Gang schließen.
Erwähnt außerdem: den 11mio Jahre alten Schwaben Udo, ein Danuvius guggenmosi , der auch schon aufrecht gehen konnte, und stellt die Bulgarin als Bindeglied zwischen Udo und den ersten, sehr viel jüngeren Funden aus Ostafrika dar.
Auch Klima wird erwähnt. Die große Abkühlung, die vor 15mio losging, hat Bulgarien vor ca 6mio Jahren regelrecht verwüstet und so migrierten Säugetiere, auch diese Oberschenkel... ^^, nach Süden, nach Afrika.
Meine Ergänzung:
in Schwaben war es da schon nicht mehr warm genug. Udo hatte vor 11mio Jahren zwar noch in Afrikanischer Pflanzenwelt gelebt, aber vor 6mio Jahren war es in Schwaben lokal halt schon ca. 20Grad kälter und auch die Alpen wölbten sich nach oben, was den Einfluss vom tropischem Mittelmeer/Afrika senkte.
hach.
Jetzt hätt ich gern noch die Einordnung, dass Afrika von 11 bis 7mio Jahre sowieso viel zu heiß gewesen ist, um große Säugetiere und aufrechtgehende Oberschenkel ^^ einen Lebensraum zu bieten.
Und dass nämlich darum die Wiege der Menschheit gerade nicht in Süd oder Ostafrika stand, sondern in Schwaben!!
https://nachrichten.idw-online.de/2026/03/04/stammt-der-aelteste-vorfahr-des-menschen-vom-balkan-ein-neues-fossil-schliesst-eine-luecke
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...
RE: https://aus.social/@Andbaker/115851475839893821
A reminder, American Geophysical Union honours nominations are open at the moment! The AGU Paleoceanography and Paleoclimatology section have three Honours available, for all career stages. Do you know of any AGU paleoclimate section members who could be nominated? Please share... #geology #Earthscience #paleoclimate #Paleoceanography
A new web interface for Berger et al's insolation calculator has been released. Check it out!
anlomedad
Dr. Evan J. Gowan
Jeff Munroe
Dr Micha Campbell
Vráble Neolithic Bodies
The-14
Andy Baker