Intensified Central Asian aridification accompanied with strengthened Asian summer monsoons at the 400-kyr band during 4–2 Ma

Central Asian wetting has been accompanied with East Asian precipitation decrease in recent decades, but whether this is the case on longer timescales is not entirely clear. Here we present new and compiled available evidence from the Qaidam Basin of Central Asia, which shows that Central Asian aridification intensification was accompanied with Asian summer monsoon intensification at 400-kyr band during 4–2 Ma. We attribute the observed intensified Central Asian aridification to increased evaporation during increased Northern Hemisphere summer insolation associated with high eccentricity, which overpowered the impact of potential moisture increase. This result indicates that the Central Asia-East Asia dry-wet out-of-phase pattern likely persists across different timescales prior to a world dominated by 100-kyr glacial cycles. •Central Asia-East Asia dry-wet variations exhibit out-of-phase pattern at 400-kyr timescale during 4–2 Ma.•Central Asia aridification intensified at high orbital eccentricity during the late Pliocene-early Pleistocene.•The intensified aridification in Central Asia was mainly caused by increased evaporation at high orbital eccentricity.