During the Pleistocene, glacial-interglacial periods have occurred regularly. Glacial ice sheet advances occur at intervals of approximately 40,000 to 100,000 years. These glacial-interglacial cycles also coincide with orbital changes of the earth which also dramatically affect volcanism, earth crustal displacement and upheavels, and other powerful natural phenomena. During interglacial periods, sea levels rise and many coastal and low lying areas around the globe flood.
We know that the last glacial period (known as the Würm glaciation) can be dated to the time about 115,000 to 11,700 years ago, We are currently living in an interglacial period (since about 11,700 years ago). Prior to the Würm glacial period, the previous interglacial period known as the Riss-Würm interglacial period reigned upon the earth, beginning around 130,000 years ago and ending around 115,000 years ago.
This glacial-interglacial cycle, where during the interglacial period there would be massive melting of ice sheets, volcanism, earth crust displacements and flooding, fits nicely with the timeline of the emergence of Homo sapiens around 200,000 years ago, followed by the first genetic split (which may have occurred around 150,000-130,00 as the previous Riss glaciation peaked and may have been a major impetus for the first migration of a population of Homo sapiens out of Eurasia and into Africa).
The Riss-Würm interglacial period (spanning 130,000 to 115,000 years ago) may have been the driving impetus moving the Homo sapiens who had remained in Eurasia during the Riss glaciation to finally begin to migrate north, which was now warmer than it had been during the Würm glacial period. During this northward migration of this population of Homo sapiens, differentiation into the three major non-African genetic clusters began to emerge. These three emergent genetic clusters bloomed into beautifully differentiating genetic clusters as they migrated further north, between 115,000 to 50,000 years ago, finally taking different paths through Eurasia.
Taking all of this together, my previous post regarding my theory of pre-human to human origins fits my own genetic data, what is known scientifically about population genetic clusters, the Chinese "Out of Asia" theory of human origins, and the folk memory of many traditions and mythologies.
(I originally published this in 2017 as a webpage.)