Antarctic ice-sheet sensitivity to obliquity forcing enhanced through ocean connections

ABSTRACT Deep sea geological records indicate that Antarctic ice-sheet growth and decay is strongly influenced by the Earth’s astronomical variations (known as Milankovitch cycles), and that

the frequency of the glacial–interglacial cycles changes through time. Here we examine the emergence of a strong obliquity (axial tilt) control on Antarctic ice-sheet evolution during the

Miocene by correlating the Antarctic margin geological records from 34 to 5 million years ago with a measure of obliquity sensitivity that compares the variance in deep sea sediment core

oxygen-isotope data at obliquity timescales with variance of the calculated obliquity forcing. Our analysis reveals distinct phases of ice-sheet evolution and suggests the sensitivity to

obliquity forcing increases when ice-sheet margins extend into marine environments. We propose that this occurs because obliquity-driven changes in the meridional temperature gradient affect

the position and strength of the circum-Antarctic easterly flow and enhance (or reduce) ocean heat transport across the Antarctic continental margin. The influence of obliquity-driven

changes in ocean dynamics is amplified when marine ice sheets are extensive, and sea ice is limited. Our reconstruction of the Antarctic ice-sheet history suggests that if sea-ice cover

decreases in the coming decades, ocean-driven melting at the ice-sheet margin will be amplified. Access through your institution Buy or subscribe This is a preview of subscription content,

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institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS THE ROLE OF OCEAN AND ATMOSPHERIC DYNAMICS IN THE MARINE-BASED COLLAPSE OF THE

LAST EURASIAN ICE SHEET Article Open access 19 May 2022 HYDROLOGICAL IMPACT OF MIDDLE MIOCENE ANTARCTIC ICE-FREE AREAS COUPLED TO DEEP OCEAN TEMPERATURES Article 13 May 2021 ANTARCTIC

ICEBERGS REORGANIZE OCEAN CIRCULATION DURING PLEISTOCENE GLACIALS Article 13 January 2021 DATA AVAILABILITY Data sets generated during and/or analysed during the current study are available

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by the New Zealand Ministry of Business Innovation and Employment contract C05X1001 (R.H.L., T.R.N., N.R.G. and R.M.M.) and by NSF grant EAR-1151438 (S.R.M.). A sabbatical leave from the

University of Wisconsin—Madison supported S.R.M to conduct research at the Institute of Geological and Nuclear Science. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * GNS Science, Lower Hutt,

New Zealand R. H. Levy, N. R. Golledge, J. S. Crampton & C. Clowes * Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand R. H. Levy, T. R. Naish, N. R.

Golledge & R. M. McKay * Department of Geoscience, University of Wisconsin—Madison, Madison, WI, USA S. R. Meyers * School of Geography, Environment and Earth Science, Victoria

University of Wellington, Wellington, New Zealand J. S. Crampton * Department of Geosciences, University of Massachusetts, Amherst, MA, USA R. M. DeConto * Istituto Nazionale di Oceanografia

e di Geofisica Sperimentale (OGS), Sgonico, Trieste, Italy L. De Santis * Istituto Nazionale di Geofisica e Vulcanologia (INGV), Roma, Italy F. Florindo * School of Geographical Sciences,

University of Bristol, Bristol, UK E. G. W. Gasson * Earth & Atmospheric Sciences, University of Nebraska, Lincoln, Lincoln, NE, USA D. M. Harwood * Earth Science Department, University

of California, Santa Barbara, Santa Barbara, CA, USA B. P. Luyendyk * Department of Geology and Environmental Geosciences, Northern Illinois University, DeKalb, IL, USA R. D. Powell *

International Ocean Discovery Program, Texas A&M University, College Station, TX, USA D. K. Kulhanek Authors * R. H. Levy View author publications You can also search for this author

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publications You can also search for this author inPubMed Google Scholar * E. G. W. Gasson View author publications You can also search for this author inPubMed Google Scholar * D. M.

Harwood View author publications You can also search for this author inPubMed Google Scholar * B. P. Luyendyk View author publications You can also search for this author inPubMed Google

Scholar * R. D. Powell View author publications You can also search for this author inPubMed Google Scholar * C. Clowes View author publications You can also search for this author inPubMed 

Google Scholar * D. K. Kulhanek View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS R.H.L. and S.R.M. conceived the project. R.H.L., T.R.N. and

R.M.M. performed the stratigraphic and proxy synthesis, and S.R.M. conducted the time series analyses. R.H.L. and S.R.M. wrote the first draft of the manuscript, in consultation with

T.R.N., N.R.G., J.S.C. and R.M.M. All the authors contributed to the interpretations and major findings of this work. CORRESPONDING AUTHOR Correspondence to R. H. Levy. ETHICS DECLARATIONS

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ice-sheet sensitivity to obliquity forcing enhanced through ocean connections. _Nature Geosci_ 12, 132–137 (2019). https://doi.org/10.1038/s41561-018-0284-4 Download citation * Received: 02

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