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Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion

Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion
Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion
Changes in sea ice significantly modulate climate change because of its high reflective and strong insulating nature. In contrast to Arctic sea ice, sea ice surrounding Antarctica has expanded1, with record extent2 in 2010. This ice expansion has previously been attributed to dynamical atmospheric changes that induce atmospheric cooling3. Here we show that accelerated basal melting of Antarctic ice shelves is likely to have contributed significantly to sea-ice expansion. Specifically, we present observations indicating that melt water from Antarctica’s ice shelves accumulates in a cool and fresh surface layer that shields the surface ocean from the warmer deeper waters that are melting the ice shelves. Simulating these processes in a coupled climate model we find that cool and fresh surface water from ice-shelf melt indeed leads to expanding sea ice in austral autumn and winter. This powerful negative feedback counteracts Southern Hemispheric atmospheric warming. Although changes in atmospheric dynamics most likely govern regional sea-ice trends4, our analyses indicate that the overall sea-ice trend is dominated by increased ice-shelf melt. We suggest that cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise.
1752-0894
376-379
Bintanja, R.
c3a0a54d-e7bb-4f39-a4db-b95092cf3bb2
van Oldenborgh, G.J.
bfed2684-7bc6-4711-b0a1-6953fd1090cb
Drijfhout, S.S.
a5c76079-179b-490c-93fe-fc0391aacf13
Wouters, B.
05ac65e0-35f5-43ae-8e80-a6ff13c1c2ef
Katsman, C.A.
12afa51e-d40c-43ce-917f-1bc7f4c7d4fb
Bintanja, R.
c3a0a54d-e7bb-4f39-a4db-b95092cf3bb2
van Oldenborgh, G.J.
bfed2684-7bc6-4711-b0a1-6953fd1090cb
Drijfhout, S.S.
a5c76079-179b-490c-93fe-fc0391aacf13
Wouters, B.
05ac65e0-35f5-43ae-8e80-a6ff13c1c2ef
Katsman, C.A.
12afa51e-d40c-43ce-917f-1bc7f4c7d4fb

Bintanja, R., van Oldenborgh, G.J., Drijfhout, S.S., Wouters, B. and Katsman, C.A. (2013) Important role for ocean warming and increased ice-shelf melt in Antarctic sea-ice expansion. Nature Geoscience, 6 (5), 376-379. (doi:10.1038/ngeo1767).

Record type: Article

Abstract

Changes in sea ice significantly modulate climate change because of its high reflective and strong insulating nature. In contrast to Arctic sea ice, sea ice surrounding Antarctica has expanded1, with record extent2 in 2010. This ice expansion has previously been attributed to dynamical atmospheric changes that induce atmospheric cooling3. Here we show that accelerated basal melting of Antarctic ice shelves is likely to have contributed significantly to sea-ice expansion. Specifically, we present observations indicating that melt water from Antarctica’s ice shelves accumulates in a cool and fresh surface layer that shields the surface ocean from the warmer deeper waters that are melting the ice shelves. Simulating these processes in a coupled climate model we find that cool and fresh surface water from ice-shelf melt indeed leads to expanding sea ice in austral autumn and winter. This powerful negative feedback counteracts Southern Hemispheric atmospheric warming. Although changes in atmospheric dynamics most likely govern regional sea-ice trends4, our analyses indicate that the overall sea-ice trend is dominated by increased ice-shelf melt. We suggest that cool sea surface temperatures around Antarctica could offset projected snowfall increases in Antarctica, with implications for estimates of future sea-level rise.

Full text not available from this repository.

More information

Published date: 31 March 2013
Organisations: Physical Oceanography

Identifiers

Local EPrints ID: 352578
URI: https://eprints.soton.ac.uk/id/eprint/352578
ISSN: 1752-0894
PURE UUID: 597a0ee8-ca12-449d-bd96-b3eb2a614d10

Catalogue record

Date deposited: 15 May 2013 14:08
Last modified: 18 Jul 2017 04:12

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