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

Sauermilch, I.; Whittaker, J.M.; Klocker, A.; Munday, D.R. ORCID: https://orcid.org/0000-0003-1920-708X; Hochmuth, K.; Bijl, P.K.; LaCasce, J.H.. 2021 Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling. Nature Communications, 12, 6465. 8, pp. 10.1038/s41467-021-26658-1

Before downloading, please read NORA policies.

Preview

Text (Open Access) Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, 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. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. s41467-021-26658-1.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (3MB) | Preview

Abstract/Summary

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 °C, up to 5 °C) 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 Type:	Publication - Article
Digital Object Identifier (DOI):	10.1038/s41467-021-26658-1
ISSN:	20411723
Date made live:	15 Nov 2021 12:18 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/531383

Actions (login required)

View Item

Document Downloads

More statistics for this item...