[TigersEye]

I know and the glacial period of an ice age (actually we’re in an ice age now it’s just the inter-glacial period) typically lasts about 90k years. Where I sit now had a three mile thick cap of ice on it during the last glacial period.

[Paul R.]

Exactly! I wish I could recall where I first saw the tagline "'Normal' is Chicago under a mile of ice."

I've posted these many times, but I suppose there's always a chance someone new to FR will come along:

That last dip (on the right, blue or green) nearly did humankind in.

Another chart:

And for a little longer perspective: