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Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling

Citation

Sauermilch, I and Whittaker, JM and Klocker, A and Munday, DR and Hochmuth, K and Bijl, PK and LaCasce, JH, Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling, Nature Communications, 12, (1) Article 6465. ISSN 2041-1723 (2021) [Refereed Article]


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Copyright Statement

The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) License, http://creativecommons.org/licenses/by/4.0/. which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

DOI: doi:10.1038/s41467-021-26658-1

Abstract

Declining atmospheric CO2 concentrations are considered the primary driver for the Cenozoic Greenhouse-Icehouse transition, ~34 million years ago. A role for tectonically opening Southern Ocean gateways, initiating the onset of a thermally isolating Antarctic Circumpolar Current, has been disputed as ocean models have not reproduced expected heat transport to the Antarctic coast. Here we use high-resolution ocean simulations with detailed paleobathymetry to demonstrate that tectonics did play a fundamental role in reorganising Southern Ocean circulation patterns and heat transport, consistent with available proxy data. When at least one gateway (Tasmanian or Drake) is shallow (300 m), gyres transport warm waters towards Antarctica. When the second gateway subsides below 300 m, these gyres weaken and cause a dramatic cooling (average of 2-4 Celsius degree, up to 5 Celsius degree) of Antarctic surface waters whilst the ACC remains weak. Our results demonstrate that tectonic changes are crucial for Southern Ocean climate change and should be carefully considered in constraining long-term climate sensitivity to CO2.

Item Details

Item Type:Refereed Article
Keywords:ocean gyres; Southern Ocean;CO2; climate change
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:Sauermilch, I (Miss Isabel Sauermilch)
UTAS Author:Whittaker, JM (Associate Professor Jo Whittaker)
UTAS Author:Klocker, A (Dr Andreas Klocker)
ID Code:152782
Year Published:2021
Web of Science® Times Cited:6
Deposited By:Oceans and Cryosphere
Deposited On:2022-08-24
Last Modified:2022-09-14
Downloads:0

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