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 šØš¦ refreezes
14.2 ky WAIS air temperature drops
14 ky Scotland refreezes.
With the exception of WAIS air Ā°C, the time resolution isn't definitive enough to answer this question ā 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? š š„
Antarctic circumpolar current is part of the AMOC ā or vice versa. Antarctic bottom water formation is part of the AMOC. And they influence each other. So...
