Arctic Warming Suppressed by Remnant Glacial Ice Sheets in Past Interglacials

Abstract

Time slice experiments for past interglacial climates of Marine Isotope Stage (MIS)1, MIS5e, and MIS11 are simulated using an atmosphere-ocean-vegetation coupled general circulation model with prescribed remnant ice sheet distributions. We examine Arctic climate responses to insolation intensity as well as remnant ice sheets through atmosphere-ocean-vegetation feedback quantitatively. During periods when Northern Hemisphere ice sheets remain, Arctic sea ice maintains a large extent in summer, and annual mean surface air temperatures are low enough to outweigh the warming expected from summer insolation intensity and greenhouse gases alone. This indicates that glacial ice sheets, due to their high albedo and their role as a heat sink, suppress the accumulation of heat in the Arctic Ocean in summer and the associated warming feedback. The results suggest a need to consider the history of remnant ice sheets and the duration of ice-free periods to explain different Arctic climate responses within and between interglacials.