Identification

Title

A weakened AMOC could cause Southern Ocean temperature and seaâ€ice change on multidecadal timescales

Abstract

We present the first CMIP6‐era multi‐model intercomparison of the Southern Ocean (SO) temperature and sea‐ice response to substantial Atlantic meridional overturning circulation (AMOC) weakening. Results are based on analysis of the North Atlantic Hosing Model Intercomparison Project, involving eight CMIP6 models under identical North Atlantic freshwater hosing. On multidecadal timescales, we find that southwards ocean heat transport into the SO increases, causing surface warming and sea‐ice loss. Additionally, an atmospheric tropical‐Antarctic teleconnection, identified here for the first time, causes regional temperature and sea‐ice changes in the SO. Unlike previous studies, we find that the Amundsen Sea Low deepens for only some models. Overall, in the multi‐model ensemble mean (multi‐model range in brackets), over years 50–100 after AMOC weakening: SO surface air temperature warms by 0.3 (0.1–0.7)°C, sea level pressure (SLP) decreases by 30 (10–70) Pa, and sea‐ice area decreases by 0.4 (−0.2–1.3) Mkm 2 . The teleconnection leads to regional differences between the response in the Indian sector and the Weddell Sea of 180 (80–320) Pa in SLP, 0.6 (0.5–1.4)°C in surface air temperature, and 0.1 (0.1–0.2) Mkm 2 in sea‐ice area. These SO heat transport, temperature, pressure, and sea‐ice changes are small relative to the changes expected under future anthropogenic warming, despite the large and idealized 0.3 Sv hosing used to weaken the AMOC.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.net/ark:/85065/d72f7sw2

codeSpace

Dataset language

eng

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Topic category

geoscientificInformation

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Text

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title

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reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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publication

effective date

2025-07-01T00:00:00Z

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<span style="font-family:Arial;font-size:10pt;font-style:normal;" data-sheets-root="1">Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</span>

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None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

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pointOfContact

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