So if we look at how the world is today, like the paragraph says, some things are very similar. Around 1.8 million years ago , there was a massive ice age that occurred . People in Central Asia migrated from that portion, up into Eastern Russia and because the ice was thick,
You could walk on it . From eastern Russia, from there people migrated into what is today , Alaska. The climate because of the ice age, helped both these civilizations . In Mesopotamia, because of the ice age, made the earth cooler, therefore rainfall in which is the Middle East. These two both have migration involved and the Ice Age . Please understand also that the "people" around this time were not Humans like today. These are a different species of humans . Hoped this helped!
