A failed human expansion out of Africa 100,000 years ago

Early modern humans expanded out of Africa multiple times before 70,000 years ago, yet noneof these populations are ancestral to living non-Africans. What caused these dispersals to fail?Here we investigate one such expansion using new evidence from southern Arabia. We presentrobust chronologies from four stratified sites in Dhofar, Oman, associated with NubianLevallois technology—a distinctive stone tool tradition of African origin. The ages constrainthis industry to 109-95 thousand years ago, synchronous with Nubian occurrences in the easternMediterranean and coinciding with the estimated timing of early modern human gene flow intoNeanderthals. Integrating our chronology with palaeoenvironmental records, we show that thesouthern Arabian population disappeared abruptly with the onset of aridification 95 thousandyears ago, with no technological continuity into later industries. These results demonstrate thatearly human expansions beyond Africa were climate-dependent and demographically fragile,and that the global establishment of our species was preceded by repeated failures.