SETTLEMENT: Astrid Lyså in August 2007 in the ruined settlement left by the Independence I Culture in North Greenland. The first immigrants to these inhospitable regions succumbed to the elements nearly 4000 years ago, when the climate became colder again. (Click for a larger image) Photo: Eiliv Larsen, NGU
The various tribes/nations in Siberia and Central Asia are known to have moved North and South with the changes in the climates. Sometimes it was perfect for grass, and sometimes less so.
Nearer the coasts ~ e.g. the Scandinavian Peninsula or Kamchatka and Korea, the changes were moderated by the ocean, but they still happened.
We can dig up their stuff and see when they lived there ~ and sometimes we can actually tell who they were.
The Turkish speaking tribes of Central Asia regularly went as far South as India and as far North as the Arctic ocean. The spans of time for these moves are enormous, but they kept the memories alive so when conditions were right they could go where they needed to go. Sometimes they took over India. Other times they didn't.
In Eastern Asia just North of India's Ganges watershed only one Turkish speaking tribe is known to have gone North to Siberia, then South to India, then back North, and so forth.
Other groups would move East or West to take advantage of better grazing lands. Yet more groups would move up and down the coastlines to hunt seal, or to fish.
Based on what people were doing in Asia it looks like the major cycles last a thousand years or so, with the smaller cycles lasting a few hundred years.
The anthropogenic global warming crowd seem to want the rest of us to believe that these cycles have stopped!
