[aerohead]

Originally Posted by freebeard

I said possibly because there may be some way of teasing out a result from isotopes and such.

I entertain the possibility that there may have been permafrost thaws at the end of each ice age.

skepticalscience.com: We've been through climate changes before

It's called 'permafrost' due to the fact that until recently it was permanently frozen.
I suppose 'relativifrost' could take it's place now. It will remain frost as a function of how warming accelerates.
We've been through climate change before, but never anthropogenically-driven climate change.
As I keep repeating, when you start a fire larger than a planet, and keep it burning from year to year, it should be no surprise when the planet turns around and bites you on the ---.