Timing and climate dynamics of centennial-scale abrupt climate change during early Marine Isotope Stage 3 inferred from the INTIMATE network

The study of centennial-scale events remains underdeveloped, with little knowledge of events timing, their inter-regional phasing, and the role played by the Atlantic Meridional Overturning Circulation (AMOC) during these events (1, 2). Here we present four high-precision speleothem δ18O records from Asian summer monsoon (ASM) and South American summer monsoon (SASM) domains, spanning a centennial-scale 55 ka event. These speleothem records are comparable to those previously published from Europe, indicates that the 55 ka event occurred simultaneously in the European and ASM domains. The synchronous timing during the centennial-sale events is consistent with what has previously been observed during millennial events (1). It is therefore likely that abrupt climate change teleconnections between North Atlantic and ASM hydroclimates would have pervasively persisted during the last glacial period. Additionally, the speleothem records were compared with the bipolar ice-core and marine sediment records of INTIMATE. The “monsoon seesaw” pattern between the ASM and SASM records over 55 ka event is consistent with a northward shift of the Intertropical Convergence Zone (ITCZ). Our study suggests that the 55 ka event was caused by AMOC reinvigoration.   Ref. (1) Corrick, E C. et al. Synchronous timing of abrupt climate changes during the last glacial period. Science 369,963-969 (2020). (2) Lynch-Stieglitz, J. The Atlantic Meridional Overturning Circulation and Abrupt Climate Change. Annual Review of Marine Science 9, 83-104 (2017).