Pleistocene Global Cooling Did Not Weaken the East Asian Summer Monsoon

Abstract The response of the East Asian summer monsoon (EASM) precipitation to Pleistocene global cooling is crucial for understanding Earth's climate and hydrological cycles. The long‐term trend of the EASM precipitation during the Pleistocene remains hotly debated with two main hypotheses: one suggesting a gradually weakening EASM driven by global cooling, whereas the other proposing a gradually intensifying EASM influenced by the uplift of the Tibetan Plateau or strengthening Pacific Walker Circulation. The primary challenge in resolving this debate lies in disentangling the temperature effects from existing monsoon precipitation proxies, which complicates the interpretation of past climate records. Here, we present a new record of Pleistocene EASM precipitation change from North China, based on soil dolomite and calcite contents that are independent of temperature. Our results indicate increased interglacial EASM precipitation but near‐constant glacial EASM precipitation in the long‐term trend. This finding challenges the conventional view that global cooling weakened monsoon precipitation. We propose that Pleistocene EASM long‐term evolution is controlled by the competition between the monsoon‐weakening effects of global cooling and the monsoon‐enhancing effects of the strengthening Walker Circulation, suggesting that even a cooling climate could strengthen monsoon precipitation. Our results hold profound implications for assessing the complex relationship between hydroclimatic cycles and global temperatures during the late Cenozoic.