In fact, the temperatures during the ice ages were only a few degree cooler than today in areas not covered by ice sheets. A wall of ice 2,000+ reached down to about Olympia in Washington state, but south of that the climate was temperate.
The Gulf Stream & its deep salt water return current may indeed shut down, but its not the trigger. The geologic record show ice ages occur in 11,000 year cycles or so, in lockstep with Sun cycles. We are, by most indications entering an ice age now. It's not us (human) warming things up & it's not the atmosphere that's warming. It's the oceans that are warming up & it's from underwater volcanoes. More ocean heat means more atmospheric water vapor & this is what is driving these "unusual" storms.
Every 1" of rain is about 10" of snow & this year we had storms in US in which 5 or more inches of rain fell in a few hours. Convert that to snow & add a 3 day storm & you have 150" of snow. No one's diggin out of that.
