[PatrickHenry]

Where in the world would there be a sure supply of food for 2-5 years? The polar regions.

Don't overlook the obvious -- canibalism.

[blam]

"Mountains would work in that respect. Thinking of 5 or so bands of humans, separated by entire continents for a few 1000 years."

You understand it. My son (visiting from LA) said cannabilism...probably some of that too.