Humidification of Central Asia and equatorward shifts of westerly wind since the late Pliocene

The production, transport, and deposition of mineral dust have a major influence on climate change and Earth’s biogeochemical cycles. Furthermore, their imprint as recorded in pelagic sediments provides an avenue for determining past changes in terrestrial aridity and atmospheric circulation patterns, which have their global consequences. Here, by examining geochemical and magnetic data derived from a ferromanganese crust in the western Pacific Ocean, we resolve the relationship between eolian dust source region conditions, transport mechanisms, and fluxes from the Asian interior to the Pacific Ocean since the Pliocene. We identify a provenance change in the dust source regions, from a dominant Gobi Desert source during the early Pliocene to a mixed Gobi-Taklimakan Desert source during the late Pliocene and Pleistocene, alongside increasing chemical weathering in those source areas. Climate model simulations suggest that these changes were related to an equatorward shift of the westerly jet and humidification of Central Asia during the Plio-Pleistocene transition. Our results provide a palaeoclimate analogue suggesting that current anthropogenic warming could systematically increase aridity over Central Asia, a region already suffering water shortages