Ocean Response in Transient Simulations of the Last Deglaciation Dominated by Underlying Ice-Sheet Reconstruction and Method of Meltwater Distribution

The last deglaciation was characterized by drastic climate changes, most prominently melting ice sheets. Melting ice sheets have a significant impact on the atmospheric and oceanic circulation, due to changes in the topography and meltwater release into the ocean. In a set of transient simulations of the last deglaciation with the Max Planck Institute for Meteorology Earth System Model we explore differences in the climate response that arise from different boundary conditions and implementations suggested within the Paleoclimate Modeling Intercomparison Project - Phase 4 (PMIP4) deglaciation protocol. The underlying ice-sheet reconstruction dominates the simulated deglacial millennial-scale climate variability in terms of timing and occurrence of observed climate events. Sensitivity experiments indicate that the location and timing of meltwater release from the ice sheets into the ocean are crucial for the ocean response. The results will allow a better interpretation of inter-model differences that arise from different implementations proposed within the PMIP4 protocol.

Automated summary

The last deglaciation period was characterized by drastic climate changes, primarily due to melting ice sheets. This study investigates the climate response differences in simulations of the last deglaciation using different boundary conditions and implementations proposed within the PMIP4 deglaciation protocol. The results reveal that the underlying ice-sheet reconstruction dominates the millennial-scale climate variability, and the timing and occurrence of observed climate events during the simulated deglacial period. The experiments also highlight the crucial role of the location and timing of ice-sheet meltwater release into the ocean on the oceanic response.