Modeling the evolution of central Asian drylands during the Cenozoic

The evolution of central Asian drylands during the Cenozoic is a hot topic in paleoclimate research, but the underlying mechanism remains unclear. Here, we investigate this topic with climate modeling based on six key geological periods. Our results indicate that central Asian drylands have existed since the early Eocene, after which they move northward and become narrower. Although changed land–sea distribution and decreased atmospheric CO2 concentration promote the aridification of drylands, they only slightly affect the latitudinal distribution of drylands. By comparison, the growth of Asian high-topography areas, especially the Tibetan Plateau (TP), makes central Asian drylands move northward, concentrate in narrow latitudinal bands, and increase in intensity. Good model-data qualitative agreement is obtained for stepwise aridification in midlatitude inland Asia north of ~40°N, and the uplifted main and northern TP by the early Miocene likely forced drylands to change in this region.