the migration to the north is always clima based and never ideology based.
back when africa started desertifying people already migrated to the north, the whole middleeast is the biggest genetic mix pool in the world. within Palestinian/israelis/persians/turks/arabs you find the biggest mix of african/asian/european/rus genetics in human evolution history.
that place is the true center of humanity, and it will always be kinda aslong as it connects 3 continental plates that are the main parts of human evolution together. since millenias that region is known as humanity's maintrading hub, and tbh that is kinda the sole reason for why wars started there and how wars continued into modern times.
my point is, migrations happened before, wars just intensified those tho. so I cut a slack there.