Exit From Africa

 From Haaretz:

Arabia isn't what it used to be. Long ago, that barren peninsula was lush, crossed by rivers and dotted with lakes. In fact, it turns out the Sahara and Arabia have a history of swinging between aridity and abundance for millions of years.

How many millions of years? When were the Sahara and by extension– the Arabian Desert – created, forming a barrier to the terrestrial movement of species between Africa and Eurasia? Different studies suggested wildly different answers for the giant desert's inception, from 2.6 million years to 7 million years. In 2022 a paper proposed that the Sahara barrier developed as much as 11 million years ago, but added that the region had experienced wet-dry cycles. (Read more.)