http://www.esd.ornl.gov/projects/qen/nerc.html
There's a link about halfway down the page that is titled " A Quick Background to the Last Ice Age " which deals with the climatic conditions prevailing in various time periods leading to the present...
It gives a good background on what sort of living conditions ancient man had to endure, and some insights into climatic changes and cycles that hint at good times among the bad..
I found it interesting that during the last 17,000 years or so, there have been several warm and cold periods, wet and dry periods, etc..
Change of climate could on occasion occur over a period of less than 100 years...
Imagine listening to your grandfather complain about how bad he had it as a kid, when it was really cold and dry, and everywhere one went was always uphill..
Oh.. Also a little lower down is a link to an article about a siberian glacial mega lake.. Much like Lake Agassi here in the northern midwest..
Given the time period, such flooding could drive some people to emigrate to relatively "safer" territory in the "new world"..
Thanks.