Tectonically Controlled Establishment of Modern‐Like Precipitation Patterns in East and Central Asia During the Early Late Miocene

Deciphering how modern precipitation patterns became established in monsoon‐dominated East Asia and the arid interior Asia is crucial for predicting future precipitation trends under accelerated global warming and increased climate extremes. However, this effort is hindered by a scarcity of quantitative paleo‐precipitation data in this region. Here we reconstruct the pattern of Middle to Late Miocene paleo‐precipitation across an east‐to‐west transect from the summer monsoon‐dominated East Asian region through the transition zone and into interior Asia. Our work is based on a newly established precipitation calculation equation and quantitative pollen‐based precipitation conversion. Analysis indicates a common trend of precipitation across the studied region prior to ca, 11 Ma, followed by a clear divergence of precipitation variations between East and interior Asia since at least 11–9 Ma. This divergence is characterized by increasing precipitation in East Asia, but a coeval decrease in rainfall in the transition zone and interior Asia. The timing of this precipitation divergence was contemporaneous with intense tectonic activity in the northern Tibetan Plateau, which differentially affected the efficacy of water vapor transport into East and interior Asia. Modeling work using different topographic settings corroborates this tectonic influence. Our study demonstrates the early establishment of modern‐like precipitation patterns in East‐interior Asia at least in the early Late Miocene. Plain Language Summary The present Asian climate consists of a monsoon‐dominated East Asia, and arid interior Asia. Increasing catastrophic flooding and storm events in monsoon region and an increasing dust storm events within interior Asia in recent years indicate an accelerated divergence in the climate conditions of these two regions. As such, deciphering how modern precipitation patterns became established in East‐interior Asia is crucial for understanding their future climate trends and mitigating possible damaging consequences. Here we developed a quantitative proxy for paleo‐precipitation and reconstruct the Middle to Late Miocene paleo‐precipitation pattern across an east‐to‐west transect from the summer‐monsoonal transition zone to interior Asia. We find that the modern precipitation pattern was established across East to interior Asia during ∼11–9 Ma, distinct with their parallel precipitation variations before this interval. We link the timing of this precipitatio