A glaciation would present a serious problem for survival of our present civilization, akin to a nuclear winter that many worried about 30 years ago.

Nuclear winter is all fantasy, of course; but ice ages are for real.

Natural warming of the Earth reached a peak 65 million years ago. The climate has been generally cooling ever since. Antarctic ice sheets started growing 25 million years ago. In the last 2.5 million years, the Earth entered the period of Ice Ages [the geological name is The Pleistocene] and has been experiencing periodic glaciations where much of the land was covered by miles-thick ice sheets.

There have been about 17 glaciations, each lasting approx. 100,000 years, separated by short inter-glacials lasting about 10,000 years.

We are approaching the likely end of the present warm inter-glacial, called The Holocene. It's time to prepare for the next glaciation to see how we can overcome it – or at least postpone its onset.