Atmospheric connections with the North Atlantic enhanced the deglacial warming in northeast China

Variations in atmospheric circulation across the last deglaciation in the northernmost monsoon-influenced regions of Asia are not well constrained, highlighting a fundamental gap in our understanding of Asian climate. Here we reconstruct continental air temperatures for northeast China across the last deglaciation (past 16 k. y.), based on the distribution of bacterial branched glycerol dialkyl glycerol tetraethers in a sequence of the Hani peat (Jilin Province, northeast China). Our results indicate large (as much as 10 degrees C) oscillations in temperature in northeast China across the deglaciation, oscillations significantly larger than observed in other temperature records from low-latitude or same-latitude East Asia, but consistent with climate model simulations. This enhanced magnitude, as well as the timing of temperature variations, provides evidence for atmospheric teleconnections with high latitudes; in particular, we suggest that highlatitude cooling associated with Arctic ice expansion and changes in Atlantic Meridional Overturning Circulation enhanced the intensity and lowered the temperature of Eurasian mid-latitude westerlies and northwesterly winds over East Asia during the last glacial, delivering cold air masses to northeast China. During the deglaciation the westerlies and therefore delivery of cold air masses weakened, amplifying the deglacial warming in this region. We conclude that changes in North Atlantic climate had a particularly strong impact on the northernmost parts of the East Asian monsoon-influenced area.