Whew! Glad I have already moved to Florida from Seattle!
They say the deal is snow covered land reflects light and cools even more and it keeps building upon itself until we have glaciers.
Suppose cheap-as-dirt salt fought it all back.
By then, food could be grown in warmer climes and indoors to feed most, I'd venture a guess. Especially if you knew it was coming. Last time during the Maunder minimum, society didn't have the technology, knowledge or means to survive, but they did. It'd be a lot easier today.
All this assumes a coming ice age is anything like the last. Fascinating. thank our lucky stars we lived in this almost ideal age.