Role of land-ocean interaction on stepwise Northern Hemisphere Glaciation

Investigation of triggers causing the onset and intensification of Northern Hemisphere Glaciation (NHG) during the late Pliocene, is essential to understand the global climate system, with important implication for projecting future climate changes. Despite their critical roles in the global climate system, influences of land-ocean interactions over high-latitude ice-sheet dynamics remain largely under explored. Here, we present a new high-resolution Asian dust record for Ocean Drilling Program Site 1208 in the North Pacific along the main route of the westerlies. Our data indicate that atmosphere-land-ocean interactions affected aeolian dust emissions through modulating moisture and vegetation in dust source regions, highlighting a critical role of terrestrial systems in initiating NHG as early as 3.6 Myr ago. Combined with additional multi-proxy and model results, we show that westerly wind strength typically in the low-to-middle troposphere, was enhanced during the major glacial events (ca. 3.3 and 2.7 Myr ago). This coupled response of Earth’s surface dynamics and atmospheric circulation to climatic changes of the Plio-Pleistocene in the Northern Hemisphere probably led to terrestrial feedbacks that affected ocean circulation and to gradual long-term global cooling.