There have also been suggestions that during ice ages the ice cap of permanently frozen sea ice might have dipped far enough south for ancient humans to have walked across the Atlantic to America. And some of the earlier tools found in US resemble Western European tools from the same timescale.
Geologist have found river beds in the Sahara, that the Mediterranean Sea at one point had pretty much dried up and CO2 was so high ferns were as tall as trees.
This planet’s climate is not dependent on man.
The Mal’ta boy, ancient boy found buried near lake Baykal in the middle of Siberia was found to be related to both Europeans and American Indians, but not to the Mongols, Chinese or other people living nearby now.