East Asian climate evolution during the Cenozoic: A review from the modeling perspective

The East Asian climate evolution during the Cenozoic era is of great importance in paleoclimate research, a fascinating topic for paleoclimatologists with efforts in both geological reconstructions and modeling studies. However, the origin of the Cenozoic East Asian monsoon climate is still debated, and the associated dynamic mechanisms remain to be elucidated. Here, we review East Asian climate evolution during the Cenozoic from the modeling perspective. Model results forced by paleogeography show that central Asian drylands existed and extended eastward to the edge of the Asian continent during the early Cenozoic. This arid climate likely retreated westward to inland Asia, and eastern China was generally wet by the late Eocene. Comparatively, the simulated East Asian summer monsoon was strong, and the winter monsoon was relatively weak during the early Eocene, partly related to the higher atmospheric CO₂ concentrations. Global cooling has caused long-term aridification and strengthened the seasonalities of the wind and precipitation in eastern China since the late Eocene. The paleogeographical evolution from the Eocene to the Miocene, particularly Tibetan Plateau growth, was likely the key factor for excessive precipitation in eastern China by strengthening the East Asian summer monsoon and central Asian aridification by blocking the water vapor supply. Together, these processes ultimately resulted in the occurrence of the modern-like East Asian monsoon climate and central Asian drylands by the early Miocene. Afterward, global cooling overrode the effect of paleogeography and mainly contributed to aridification in eastern China during the late Miocene.