I found it curious that this research only went back 450 years or so, since that takes you back to just before the Little Ice Age, a time of unusually cold temperatures, at least in the Northern Hemisphere. One wonders what they would have found had they kept going further back in time.

BTW, they already know that a lot of the melting in Greenland is from the bottom up (geothermal) rather than from the top down. But of course you don't hear too much about that, do you?

https://www.newsweek.com/puzzling-heat-deep-inside-earth-mel...