My girlie chart with 490ky years of #Milankovic cycles, CO2, sea level, and the top line is d18O of a sediment core from within the #ColdBlob, see map. I think, it records AMOC shutdowns in the past.

Would be intriguing to know why it shut down. Eg, 427ka, "just" before the interglacial MIS11.
And why it not shut down during that very long interglacial which was ~as warm as the Holocene,
and had an ice-free West #Greenland (with a leaf found just 2 years ago at rock-bottom of an ice core from there),

and why AMOC instead collapsed in the middle of the following #iceage.

The very long interglacial MIS11 with its ice-free West Greenland and stable AMOC throughout tells me that the amount of freshwater input from melting ice on its own isn't the trigger for a collapse. But instead, the speed at which freshwater is added: very slowly like during #MIS11 won't do it.

Also intriguing: why the stuttering motor during the last glacial before the #Holocene?

#d18O from sediment cores at other locations strictly follow the ups and downs of #sealevel and #CO2. This one site #IODP #U1308 is exceptional.
#paleoclimate #AMOC

Weird. Maybe, I've got a logical mistake in my thinking

Will #Steffen et al 2018 https://www.pnas.org/doi/10.1073/pnas.1810141115 warned in "Trajectories of the Earth System in the Anthropocene" of a "Hot House Earth" .
A term that got negative press all over and the paper is still discredited in public opinion among the non-scientific community, at least.
A Hot House Age is merely the term for an ice-less age in which the poles are not covered by kilometres of ice. That is called an Ice House Age.

#Talento et al 2021 https://esd.copernicus.org/articles/12/1275/2021/ modelled what happens to ice ages #glacial |s in several emission scenarios.
Today's CO2 concentration is already moving the next #iceage to later than what the #Milankovic cycles would dictate.
Scenarios for (in my opinion fictitious, unachievable) emissions of 1000 or 3000 Pg C move the next fullblown ice age to 600ky and 900ky from now.
Almost a million years. No ice age.

But the #AMOC is going to collapse: the convection in the Subpolar Gyre in the 2030s; the Northern branch of AMOC might tip before 2050 to later inevitably collapse, too.

Certainly that increases ice mass in Greenland, Europe, and Eurasia, and Arctic Sea Ice grows back, too. And all this AMOC-related ice grows and grows, each year puts more snow on the ever increasing ice layer.
I don't know how much ice is needed to meet criteria for a glacial definition.
But all that Eurasian ice also buries the boreal forests under it, ie removes their carbon from the cycle. And puts an ice plug on leaking methane from #permafrost in that area. (Tho not the permafrost in the far East. I gather, that area is not prone to ice sheets from Atlantic influences and needs other triggers to form? It wasn't covered by ice in #MIS11, 420ky ago. )

Weird isn't it, that ice mass models like Talento's don't factor in ever-increasing ice mass in low-to medium emission scenarios. Hm.

@DrEvanGowan
I went looking and found one from 673.3ky to 240ky. It's #KerstinBraun et al 2023, data https://doi.pangaea.de/10.1594/PANGAEA.957457
5 stalagmites from the same cave – and look, how very different their d18O and 13C are. The ups and downs are sometimes congruent and sometimes a thousand years apart?!
The top 2 charts only show the 2 longest records.

But #MIS11 is covered in full and their location is important for #AMOC research:
33.73S°, 19.77E°
💃

Just remembered having read a paper this year where a team had drilled an #IceCore in the West of #Greenland and at the bottom of the core, where the drill had literally hit rock bottom, they ... found a plant leaf.
Indicating that West Greenland was not only ice free but ice free for long enough so soil for plant growth had existed.
The plant grew 400 thousand years ago in #MIS11 and the climate was 1.2C over pre industrial.

When I remembered, this paper just now, a plot occurred to me for a future novel on paleo climate scientists who look at West Greenland again. Like, maybe 400 thousand years into the future, when there will have been 3 more glacials with Greenland fully covered in ice. What will they find when their drill hits rock bottom?

We should place a #Tesla at the site where they found that plant leaf this year. Just put it on top of the still existing ice. It's heavy enough so it'll just sink lower and lower and also stay put once all ice has washed to the sea...

The #USArmy planned to hide #nuclearweapons in ice tunnels in north-west #Greenland in the 1960s.

An #icecore taken during the operation was rediscovered in 2018.

Analysis of the core shows north-west Greenland was ice free during Marine #isotope Stage 11 (#MIS11 ), which occurred between 426,000 and 396,000 years ago, when #temperatures were similar to today.

#climate #paleoclimate #icesheet #glaciology

https://www.abc.net.au/news/science/2023-07-21/greenland-ice-core-secret-us-army-base-reveals-dramatic-melting/102609654?utm_source=abc_news_web&utm_medium=content_shared&utm_campaign=abc_news_web