Multidecadal warming of Antarctic waters
Bringing up the problem of ice shelf melting
Warm water intruding from below is heating up the ocean that covers the continental shelf of Antarctica. Schmidtko et al. report that Circumpolar Deep Water has been warming and moving further up onto the shelf around Antarctica for the past 40 years, causing higher rates of ice sheet melting (see the Perspective by Gille). These observations need to be taken into account when considering the potential for irreversible retreat of parts of the West Antarctic Ice Sheet.
Abstract
Decadal trends in the properties of seawater adjacent to Antarctica are poorly known, and the mechanisms responsible for such changes are uncertain. Antarctic ice sheet mass loss is largely driven by ice shelf basal melt, which is influenced by ocean-ice interactions and has been correlated with Antarctic Continental Shelf Bottom Water (ASBW) temperature. We document the spatial distribution of long-term large-scale trends in temperature, salinity, and core depth over the Antarctic continental shelf and slope. Warming at the seabed in the Bellingshausen and Amundsen seas is linked to increased heat content and to a shoaling of the mid-depth temperature maximum over the continental slope, allowing warmer, saltier water greater access to the shelf in recent years. Regions of ASBW warming are those exhibiting increased ice shelf melt.
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Supplementary Material
Summary
Materials and Methods
Figs. S1 to S11
Table S1
Resources
File (schmidtko.sm.pdf)
References and Notes
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Published In
Science
Volume 346 | Issue 6214
5 December 2014
5 December 2014
Copyright
Copyright © 2014, American Association for the Advancement of Science.
Submission history
Received: 15 May 2014
Accepted: 27 October 2014
Published in print: 5 December 2014
Acknowledgments
All data used in this manuscript are publicly available; data sources are detailed in the supplementary materials. We thank all officers, crews, and scientists involved in collecting and calibrating the data in the often harsh Southern Ocean environment, as well as everyone involved in making the data publicly available. We thank three anonymous reviewers for helpful discussions and feedback. Supported by the German Federal Ministry for Education and Research (BMBF) project MiKlip (S.S.); NERC Antarctic Funding Initiative research grant GENTOO NE/H01439X/1 (S.S. and K.J.H.); a Grant-in-Aid for Scientific Research of the Ministry of Education, Culture, Sports, Science and Technology, Japan, and a Daiwa Foundation Small Grant (S.A.); and NSF award OPP-1246460 (A.F.T.).
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