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 none of 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 present robust chronologies from four stratified sites in Dhofar, Oman, associated with Nubian Levallois technology—a distinctive stone tool tradition of African origin. The ages constrain this industry to 109-95 thousand years ago, synchronous with Nubian occurrences in the eastern Mediterranean and coinciding with the estimated timing of early modern human gene flow into Neanderthals. Integrating our chronology with palaeoenvironmental records, we show that the southern Arabian population disappeared abruptly with the onset of aridification 95 thousand years ago, with no technological continuity into later industries. These results demonstrate that early human expansions beyond Africa were climate-dependent and demographically fragile, and that the global establishment of our species was preceded by repeated failures.