Orbital modulation of an intensified hydrological cycle during the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM, -56 Ma) was an abrupt global warming event linked to massive carbon release into the ocean-atmosphere system. As such, it is considered a potentially useful analogue for present and future climate change. Consequently, deciphering its impact on the hydroclimate is important for predicting future changes under high p CO 2 and temperature conditions, especially in East Asia where more than a quarter of the world 's population lives. Here, we use magnetic and geochemical data obtained through a thick lacustrine record of the PETM from China to demonstrate a large-scale increase in weathering and precipitation coeval with the PETM. Moreover, we show that precipitation variations through the PETM were strongly controlled by eccentricity, precession and half-precession climate cycles. Our results show that orbital forcing of low-latitude insolation played a key role in driving hydroclimate fluctuations and multi -phase changes in precipitation during the PETM, emphasizing the sensitivity of East Asian hydroclimate to subtle changes in insolation under conditions of high temperature and p CO 2 , perhaps similar to those expected in the future.