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Ocean-driven thinning enhances iceberg calving and retreat of Antarctic ice shelves

journal contribution
posted on 2023-05-18, 09:18 authored by Liu, Y, Moore, JC, Cheng, X, Gladstone, RM, Bassis, JN, Liu, H, Wen, J, Hui, F
Iceberg calving from all Antarctic ice shelves has never been directly measured, despite playing a crucial role in ice sheet mass balance. Rapid changes to iceberg calving naturally arise from the sporadic detachment of large tabular bergs but can also be triggered by climate forcing. Here we provide a direct empirical estimate of mass loss due to iceberg calving and melting from Antarctic ice shelves. We find that between 2005 and 2011, the total mass loss due to iceberg calving of 755 ± 24 gigatonnes per year (Gt/y) is only half the total loss due to basal melt of 1516 ± 106 Gt/y. However, we observe widespread retreat of ice shelves that are currently thinning. Net mass loss due to iceberg calving for these ice shelves (302 ± 27 Gt/y) is comparable in magnitude to net mass loss due to basal melt (312 ± 14 Gt/y). Moreover, we find that iceberg calving from these decaying ice shelves is dominated by frequent calving events, which are distinct from the less frequent detachment of isolated tabular icebergs associated with ice shelves in neutral or positive mass balance regimes. Our results suggest that thinning associated with ocean-driven increased basal melt can trigger increased iceberg calving, implying that iceberg calving may play an overlooked role in the demise of shrinking ice shelves, and is more sensitive to ocean forcing than expected from steady state calving estimates.

History

Publication title

Proceedings of the National Academy of Sciences of the United States of America

Volume

112

Issue

11

Pagination

3263-3268

ISSN

0027-8424

Department/School

Institute for Marine and Antarctic Studies

Publisher

Natl Acad Sciences

Place of publication

2101 Constitution Ave Nw, Washington, USA, Dc, 20418

Rights statement

Copyright 2015 PNAS

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the earth sciences

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