Centennial-scale Holocene climate variations amplified by An

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TitleCentennial-scale Holocene climate variations amplified by Antarctic Ice Sheet dischargeAbstractProxy-based indicators of past climate change show that current global climate models systematically underestimate Holocene-epoch climate variability on centennial to multi-millennial timescales, with the mismatch increasing for longer periods. Proposed explanations for the discrepancy include ocean-atmosphere coupling that is too weak in models, insufficient energy cascades from smaller to larger spatial and temporal scales, or that global climate models do not consider slow climate feedbacks related to the carbon cycle or interactions between ice sheets and climate. Such interactions, however, are known to have strongly affected centennial- to orbital-scale climate variability during past glaciations, and are likely to be important in future climate change. Here we show that fluctuations in Antarctic Ice Sheet discharge caused by relatively small changes in subsurface ocean temperature can amplify multi-centennial climate variability regionally and globally, suggesting that a dynamic Antarctic Ice Sheet may have driven climate fluctuations during the Holocene. We analysed high-temporal-resolution records of iceberg-rafted debris derived from the Antarctic Ice Sheet, and performed both high-spatial-resolution ice-sheet modelling of the Antarctic Ice Sheet and multi-millennial global climate model simulations. Ice-sheet responses to decadal-scale ocean forcing appear to be less important, possibly indicating that the future response of the Antarctic Ice Sheet will be governed more by long-term anthropogenic warming combined with multi-centennial natural variability than by annual or decadal climate oscillations. Copyright 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.AcknowledgementsThis work was supported by a grant from the National Oceanographic and Atmospheric Administration (award number NA15OAR4310239 to P.B. and A.S.), the Antarctic Glaciology Program of the National Science Foundation (grant number 1043517 to P.U.C.), the Royal Society of New ZealandÅ› Marsden Fund (grant number VUW1203 to N.R.G.) and the Deutsche Forschungsgemeinschaft (DFG grant number We2039/8-1 to M.E.W.). We thank L. Menviel for providing us with the LOVECLIM-based Southern Ocean subsurface temperature data. Development of PISM is supported by NASA grants NNX13AM16G and NNX13AK27G.Funding Details1043517, NSF, National Science Foundation; NNX13AK27G, NASA, National Aeronautics and Space Administration; NNX13AM16G, NASA, National Aeronautics and Space Administration; We2039/8-1, DFG, Deutsche Forschungsgemeinschaft

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1st AuthorBakker, P.AuthorBakker, P.Clark, P.Golledge, N.Schmittner, A.Weber, M.Year2017JournalNatureVolume541Number7635Pages72-76DOI10.1038/nature20582URLhttps://www.scopus.com/inward/recor.....c33018d9c6874061a25a2adef

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TypeArticleCitationBakker, P., Clark, P., Golledge, N., Schmittner, A. and Weber, M. (2017). Centennial-scale Holocene climate variations amplified by Antarctic Ice Sheet discharge. Nature, 541(7635): 72-76IdentifierBakker2017Antarctica NZ supported?YesNZARI?No