Climate change as a draw bridge between Africa and the Middle East

Since the very beginning of the human race, the Middle East served as a bridge between Africa–where our species first evolved–and the rest of the world. The passage over this bridge opened and closed with the global fluctuations of climate. The first glacial periods at the beginning of the Quaternary caused the greenhouse of equatorial Africa to become less hospitable, while making the desert belt of the Middle East more humid, green, and thus passable. Flint tools found along the shores of dried up lakes and swamps in the Negev Desert provide evidence that members of the first wave, Homo erectus, as well as the last wave, Homo sapiens, camped there en route to all the other continents.