Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole

Abstract Most oceans over the globe have experienced surface warming during the past century, but the subpolar Atlantic is quite otherwise. The sea surface temperature cooling trend to the south of Greenland, known as the North Atlantic Warming Hole, has raised debate over whether it is driven by th...

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Main Authors: Kai-Yuan Li, Wei Liu
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Communications Earth & Environment
Online Access:https://doi.org/10.1038/s43247-025-02403-0
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author Kai-Yuan Li
Wei Liu
author_facet Kai-Yuan Li
Wei Liu
author_sort Kai-Yuan Li
collection DOAJ
description Abstract Most oceans over the globe have experienced surface warming during the past century, but the subpolar Atlantic is quite otherwise. The sea surface temperature cooling trend to the south of Greenland, known as the North Atlantic Warming Hole, has raised debate over whether it is driven by the slowing of the Atlantic Meridional Overturning Circulation. Here we use observations as a benchmark and climate models as a tool to demonstrate that only models simulating a weakened historical Atlantic overturning can broadly reproduce the observed cooling and freshening in the warming hole region. This, in turn, indicates that the realistic Atlantic overturning slowed between 1900 and 2005, at a rate of −1.01 to −2.97 Sv century−1 (1 Sv = 106 m3 s−1), according to a sea-surface-temperature-based fingerprint index estimate. Particularly, the Atlantic overturning slowdown causes an oceanic heat transport divergence across the subpolar North Atlantic, which, while partially offset by enhanced ocean heat uptake, results in cooling over the warming hole region.
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spelling doaj-art-63d9abea354c45f787f7b1bddce241a72025-08-20T02:00:00ZengNature PortfolioCommunications Earth & Environment2662-44352025-05-016111010.1038/s43247-025-02403-0Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming HoleKai-Yuan Li0Wei Liu1Department of Earth and Planetary Sciences, University of California RiversideDepartment of Earth and Planetary Sciences, University of California RiversideAbstract Most oceans over the globe have experienced surface warming during the past century, but the subpolar Atlantic is quite otherwise. The sea surface temperature cooling trend to the south of Greenland, known as the North Atlantic Warming Hole, has raised debate over whether it is driven by the slowing of the Atlantic Meridional Overturning Circulation. Here we use observations as a benchmark and climate models as a tool to demonstrate that only models simulating a weakened historical Atlantic overturning can broadly reproduce the observed cooling and freshening in the warming hole region. This, in turn, indicates that the realistic Atlantic overturning slowed between 1900 and 2005, at a rate of −1.01 to −2.97 Sv century−1 (1 Sv = 106 m3 s−1), according to a sea-surface-temperature-based fingerprint index estimate. Particularly, the Atlantic overturning slowdown causes an oceanic heat transport divergence across the subpolar North Atlantic, which, while partially offset by enhanced ocean heat uptake, results in cooling over the warming hole region.https://doi.org/10.1038/s43247-025-02403-0
spellingShingle Kai-Yuan Li
Wei Liu
Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole
Communications Earth & Environment
title Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole
title_full Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole
title_fullStr Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole
title_full_unstemmed Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole
title_short Weakened Atlantic Meridional Overturning Circulation causes the historical North Atlantic Warming Hole
title_sort weakened atlantic meridional overturning circulation causes the historical north atlantic warming hole
url https://doi.org/10.1038/s43247-025-02403-0
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