Cooler and drier climate in the South Central Pacific during the last glacial period

In the South-East Pacific, understanding how precipitation will respond to changes in temperature is crucial in anticipating future climate changes. However, our understanding of the regional climate temperature sensitivity is limited by a lack of any long-term paleoclimate reconstructions which extend before the climatically stable Holocene. To address this knowledge gap,we reconstruct temperature and precipitation using biomarker and pollen proxies sampled from a 50\,ka year-long sediment core located in Nuku Hiva (French Polynesia). The hydrogen isotopic composition of plant waxes is more positive during the last glacial period indicating drier conditions. Pollen analysis indicates that allwetter cloud forest species decreased in abundance in the glacial period, whilst drier-adapted herbaceous taxa increased. Temperature-sensitive bacterial lipids indicate much cooler conditions in the glacial period than in the Holocene. Crucially, changes in reconstructed temperature and precipitation are highly correlated over this time period, which is at odds with state-of-the-art modelling studies. These results willaid models in predicting future changes in precipitation in a region already experiencing the devastating effects of anthropogenic climate change.