Less Dryland Aridity During Pliocene Warmth

Because of the potential similarities of the climate in the mid-Pliocene to the projected conditions in the near future, studying mid-Pliocene dryland aridity can advance our future projections. In this study, we used climate modeling to investigate mid-Pliocene dryland aridity. Our results indicated that, in the mid-Pliocene compared to the preindustrial period, the simulated dryland was substantially less arid in North Africa, the Arabian Peninsula, Australia and Central Asia and more arid in North and South America and Southern Africa. The combined topography, vegetation and lakes (TVL) and atmospheric CO2 concentrations markedly modified this large-scale dryland aridity, mainly by modulating precipitation and potential evapotranspiration, respectively. Moreover, the dryland aridity during the mid-Pliocene varied under different orbital parameter intervals, mainly through precipitation changes. Our results show the important effect of vegetation on dryland aridity in a previous warm period and imply the potential effect of vegetation on future dryland aridity.