Elizabeth Childs wrote:
> It's worth noting that human beings were around for hundreds of
> thousands of years without advancing past the stone age. Then, the ice
> age ended, only 11,000 years ago and very shortly thereafter, enormous
> advances occurred in a relatively short time.
>
> Apparently, the earth has for a very long time gone through long ice
> ages broken up by brief warm periods, lasting about 10,000 years. We're
> overdue for another one.
Some claim that it started early in the christian era and only modern pollution is holding it off. The "Little Ice Age" is well documented in terms of its weather patterns, but not the causes of its rise and fall.
Chatting with my cousin, the ice age geologist, he said the last interglacial period was 36,000 years ago, which meant there was plenty of time then for a human civilization to arise. Unfortunately there is little evidence from that far back that has been preserved beyond bones. Of course, the areas where civilizations have arisen in this interglacial period have actually not seen polar ice sheets for millions, if not hundreds of millions of years, when those contenents were near or on a polar cap.