OK, so the Sahara has been an impediment to migration for seven million years, less occasional, geologically brief wet periods.
Did you actually read my links? It swung back and forth regularly between wet and dry, it was not “occasional” anomalous periods.
The current state and extent of the Sahara is partly an anthropogenic phenomenon - global warming and overgrazing aren’t helping.
But the point is that the Sahara is much more of a barrier to migration and trade than the Mediterranean. The Mediterranean isn’t a barrier to migration and trade, it promotes migration and trade.
And so in the classical era North Africa wasn’t isolated, it was just the southern shore of the pan-Mediterranean world.
Yep. In a sense it was as if the Mediterranean was center of the world!
I read the last three and skimmed (a bit too quickly, I suppose) the first. I suppose my mistake was in thinking that your list of events was meant to be exhaustive.