Climate and Ice during the Last Interglacial

During the Last Interglacial (129-116 thousand years ago, ka) CO₂ and global temperature were both higher than they were before human industrialisation. By examining Last Interglacial climate, we thus gain insights into climate processes and feedbacks close to those expected by the end of the 21^st century. For example, if we understand Last Interglacial changes in the Greenland and Antarctic ice sheets, this helps constrain the likelihood of future Greenland and Antarctic ice sheet melt – and their subsequent contribution to global sea level rise.

The research of the BAS Paleoclimate Group follows an integrative approach. The combination of paleodata with climate modelling develops our understanding of the Last Interglacial climate and of why the climate and ice sheets changed during this time. We focus on the evolution of the climate and environment over the polar ice sheets and polar oceans. For this we use paleoclimatic archives, particularly polar ice and marine sediment cores. For example, whilst stable water isotopes and impurity content of ice cores can tell us about atmospheric temperature and circulation, stable isotope ratios of foraminifera in marine cores provide invaluable information about change in the oceans.

Alongside the interpretation of the measurements, a major challenge is to define robust chronologies for these different ice and marine archives. Recently we made significant progress on this challenge, when we produced the first data synthesis covering the Last Interglacial with updated and coherent ice-marine age models. As a result we have now identified the temporal and spatial imprint of Last Interglacial changes across high-latitudes regions (Figure). This new data synthesis allows models to be tested, helping us determine whether they can accurately predict environmental and climate changes in our warming world.