Distinct effects of Tibetan Plateau growth and global cooling on the eastern and central Asian climates during the Cenozoic

Abstract

The evolution of the climate in eastern and central Asia during the Cenozoic was affected by regional paleogeographic developments and global climate change. Previous studies have mainly investigated the effects of Tibetan Plateau (TP) growth and global cooling for specific time periods. However, the respective contributions of these two factors over time are still poorly understood. In this study, we comprehensively compared the effects of TP growth and secular climate change by integrating existing paleobotanical records and model results across a total of 67 experiments. Our results demonstrate that the effects of TP growth and global cooling on the eastern and central Asian climates differed. During the early Eocene, high atmospheric CO2 concentrations contributed greatly to the relatively wet conditions in eastern and central Asia. Subsequent global cooling tended to cause long-term aridification in eastern Asia. By comparison, TP growth was the key factor for the increasing precipitation in eastern Asia and the decreasing precipitation in central Asia between the late Oligocene and the early Miocene. High atmospheric CO2 concentrations contributed to the increased wetness in eastern Asia in the geological past, and this fact has far-reaching implications for future wetter conditions in this region under anthropogenic forcing.