“Examination of several proxy records (e.g., sediment cores) of sea ice indicate ice-free or near ice-free summer conditions for at least some time during the period of 15,000 to 5,000 years ago”
The Polar Bears must have gone extinct. And the Walruses. I’ll bet the Penguins died off in Antarctica too.
According to John Holdren and James Hansen, an ice free Arctic would also make the planet uninhabitable by humans.
“If you find yourself alone, riding in green fields with the sun on your face, do not be troubled. For you are in Elysium and you are already dead!”