Abstract

Past Interglacials – in opposition to glacial periods – are associated to global warm climatic conditions that can be compared to the ones of the current interglacial period: the Holocene. Free from any anthropogenic interference, they are expected to bring useful information about natural climate variability during warm periods and help at the same time to better understand our present climate evolution.

The EPICA Dome C (EDC) ice core, by providing multi-proxy records of climate variations over the last 800 000 years (800 kyr), has documented in details the orbital-scale variability of 9 interglacial periods, from the Holocene or MIS (Marine Isotopic Stage) 1 to the late MIS 19 . If their shape, intensity and duration have been more precisely characterized, the high frequency variability during interglacial periods remains poorly explored, because of a lack of sufficient temporal resolution. Based on new high resolution isotopic measurements conducted on the EDC core, we here highlight new features of climate variability during interglacial periods at millennial to sub-millennial scale.

Because of climatic features of interest for a comparison with the Holocene, we specifically focus on MIS 19 , 11 and 5. Despite a temporal resolution improved by a factor of 5, our results do not reveal any added climatic information during MIS 19 . The impact of an enhanced isotopic diffusion at the bottom part of the EDC core is here evidenced. Albeit frustratring, these results are of prime importance for future projects, which aim to find the best Antarctic site to go further than 1 million years ago. The added value of measuring high resolution EDC samples for characterizing sub-millennial climate variability during past interglacials is then confirmed regarding MIS 11 and 5 results. The newly revealed climatic information is characterized in terms of (i) level of variability and (ii) distribution of changes over the course of the two interglacials. Our results lead us to analyze the links between long-term trends and high frequency variability and compare our findings with the Holocene features.