Heather Stoll

Abrupt climate changes during Termination III in Southern Europe

Significance We present an outstanding speleothem record that reconstructs the vegetation activity and hydrological availability during Termination III (T-III) in Southern Europe throughout δ13C, δ18O, and Mg/Ca variations. The results reveal for the North Atlantic region the sequence of abrupt stadial events during T-III, in close analogy to the Asian Monsoon changes reconstructed from Chinese speleothems. The two stadials identified in this record (S8.1 and S8.2) have similarities with Heinrich 1 and Heinrich 2 events in Termination I in terms of changes in the phasing of benthic δ18O, rise of semidesert pollen taxa, and ice-rafted debris release. The Late Quaternary glacial–interglacial transitions represent the highest amplitude climate changes over the last million years. Unraveling the sequence of events and feedbacks at Termination III (T-III), including potential abrupt climate reversals similar to those of the last Termination, has been particularly challenging due to the scarcity of well-dated records worldwide. Here, we present speleothem data from southern Europe covering the interval from 262.7 to 217.9 kyBP, including the transition from marine isotope stage (MIS) 8 to MIS 7e. High-resolution δ13C, δ18O, and Mg/Ca profiles reveal major millennial-scale changes in aridity manifested in changing water availability and vegetation productivity. uranium–thorium dates provide a solid chronology for two millennial-scale events (S8.1 and S8.2) which, compared with the last two terminations, has some common features with Heinrich 1 and Heinrich 2 in Termination I (T-I).