Perspective on ice age Terminations from absolute chronologies provided by global speleothem records

Glacial Terminations represent the largest amplitude climate changes of the last several million years.  Over ~ 10 ky timescale, large northern hemisphere ice sheets retreat and sea level rises, and atmospheric CO2 and global temperatures make a full transition from glacial to interglacial levels.  Several possible orbital-insolation triggers have been described to initiate and sustain glacial Terminations, and feedbacks between ice sheet retreat, ocean circulation and ocean carbon storage are invoked to explain the unstoppable progression.  Because of the availability of radiocarbon dating, the most recent termination (TI) has been extensively characterized. Yet, it is widely discussed whether this sequence of feedbacks and millennial events, and rate of warming is recurrent over previous Terminations or is unique.  Beyond the limit of radiocarbon dating, the chronologies of climate records from ice and marine cores are often developed by tuning to orbital parameters which limits their use in understanding climate dynamics, particularly the response to orbital forcing. Speleothems provide absolute age control and high-resolution proxy measurements. This archive therefore provides unique records of climate change across Terminations, and additionally may provide the opportunity to tune ice and marine core archives.  However, speleothem climate signals are encoded in a number of proxies. Unlike proxies in other archives like ice or marine cores, the climatic interpretation of a given proxy can vary quite significantly among different regions. In this study, we synthesize the available speleothem records providing climate information for Terminations: TII, TIII, TIV and TV. present the records based on the aspect of climate encoded in the available records. examine the effects of different ice volume corrections on the final climate proxy record. evaluate whether there are leads and lags in the manifestation of Terminations across different aspects of the climate systems and different regions. we speculate on suitable tuning targets among marine and ice core proxies, and discuss what model outputs maybe most suitable for comparison.