Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 12, 1919-1932, 2016
https://doi.org/10.5194/cp-12-1919-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
29 Sep 2016
Impact of meltwater on high-latitude early Last Interglacial climate
Emma J. Stone1, Emilie Capron2,3, Daniel J. Lunt1, Antony J. Payne1, Joy S. Singarayer4, Paul J. Valdes1, and Eric W. Wolff5 1BRIDGE, School of Geographical Sciences, University of Bristol, Bristol, UK
2British Antarctic Survey, Cambridge, UK
3Centre for ice and Climate, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
4Department of Meteorology, University of Reading, Reading, UK
5Department of Earth Sciences, University of Cambridge, Cambridge, UK
Abstract. Recent data compilations of the early Last Interglacial period have indicated a bipolar temperature response at 130 ka, with colder-than-present temperatures in the North Atlantic and warmer-than-present temperatures in the Southern Ocean and over Antarctica. However, climate model simulations of this period have been unable to reproduce this response, when only orbital and greenhouse gas forcings are considered in a climate model framework. Using a full-complexity general circulation model we perform climate model simulations representative of 130 ka conditions which include a magnitude of freshwater forcing derived from data at this time. We show that this meltwater from the remnant Northern Hemisphere ice sheets during the glacial–interglacial transition produces a modelled climate response similar to the observed colder-than-present temperatures in the North Atlantic at 130 ka and also results in warmer-than-present temperatures in the Southern Ocean via the bipolar seesaw mechanism. Further simulations in which the West Antarctic Ice Sheet is also removed lead to warming in East Antarctica and the Southern Ocean but do not appreciably improve the model–data comparison. This integrated model–data approach provides evidence that Northern Hemisphere freshwater forcing is an important player in the evolution of early Last Interglacial climate.

Citation: Stone, E. J., Capron, E., Lunt, D. J., Payne, A. J., Singarayer, J. S., Valdes, P. J., and Wolff, E. W.: Impact of meltwater on high-latitude early Last Interglacial climate, Clim. Past, 12, 1919-1932, https://doi.org/10.5194/cp-12-1919-2016, 2016.
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Short summary
Climate models forced only with greenhouse gas concentrations and orbital parameters representative of the early Last Interglacial are unable to reproduce the observed colder-than-present temperatures in the North Atlantic and the warmer-than-present temperatures in the Southern Hemisphere. Using a climate model forced also with a freshwater amount derived from data representing melting from the remnant Northern Hemisphere ice sheets accounts for this response via the bipolar seesaw mechanism.
Climate models forced only with greenhouse gas concentrations and orbital parameters...
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