Arabian hydroclimate and hominin population dynamics over the last 500,000 years

Despite the discovery of a rich Palaeolithic archaeological record in Arabia over the last decade, the environmental context of hominin occupations and dispersals remains poorly understood owing to the paucity of Pleistocene palaeoenvironmental records. Here we show a multi-proxy, high-resolution dust record from the western equatorial Indian Ocean spanning the last 500,000 years, which enables evaluation of the influence of orbital-scale hydrological variations on hominin populations in Arabia. The dust evidence reinforces the view that hominin presence in Arabia was driven by enhanced monsoon precipitation during so-called Green Arabia periods. These results, coupled with hunter-gatherer demographic data, point to marked hominin population expansions during prolonged wetter periods. Hominin occupation, however, was not linked exclusively to traditional humid periods. Brief phases of high-intensity rainfall within some glacial periods, manifested by transient high dust contents associated with enhanced terrestrial moisture availability and increased supply of wind-erodible particles, also favoured hominin expansions.