[aerohead]

I watched a rebroadcast of this 2020 production Wednesday morning. I hadn't seen it.
Briefly,
They showed the paleoclimate profile over the last four ice -ages, interglacials, interstadials.
The 'warm' 'HOT-HOUSE' Earth episodes were much longer then the short, 'cooler' ' SNOWBALL ' Earth episodes, as we're presently living within.
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What stuck out from the program was that, you can't have sea ice without first having land ice ( this was new to me ).
Antarctica was easy: snow accumulated, compressed to firn ice, then ice, on the 'continent', then spread into the oceans surrounding it as ice-shelves, cut off from warm water by the Drake Passage and Antarctic Circumpolar Current.'
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In the Arctic, Ice only began on Greenland, Ellesmere Island etc., and from 'land' was finally able to take hold over the Arctic Ocean.
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As the land-based glaciers disappear, leaving exposed rock and soil, it appears that Earth will lose it's only mechanism for the creation of sea ice, Earth's enormous solar reflectors.