Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)

Abstract We use the coupled atmosphere‐ocean model MIROC4m to investigate the effect of mid‐Pliocene boundary conditions on the Atlantic Meridional Overturning Circulation (AMOC), studying the impact of increased CO2, reduced ice sheets and altered orography and vegetation. We find that a higher CO2...

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Main Authors: Julia E. Weiffenbach, Wing‐Le Chan, Ayako Abe‐Ouchi, Anna S. von derHeydt
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL113118
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author Julia E. Weiffenbach
Wing‐Le Chan
Ayako Abe‐Ouchi
Anna S. von derHeydt
author_facet Julia E. Weiffenbach
Wing‐Le Chan
Ayako Abe‐Ouchi
Anna S. von derHeydt
author_sort Julia E. Weiffenbach
collection DOAJ
description Abstract We use the coupled atmosphere‐ocean model MIROC4m to investigate the effect of mid‐Pliocene boundary conditions on the Atlantic Meridional Overturning Circulation (AMOC), studying the impact of increased CO2, reduced ice sheets and altered orography and vegetation. We find that a higher CO2 concentration and smaller ice sheets both weaken the AMOC with respect to the pre‐industrial. The stronger mid‐Pliocene AMOC is therefore a consequence of mid‐Pliocene orography and vegetation, where the closed Arctic gateways are responsible for approximately 80% of the AMOC strengthening. The main mechanism for mid‐Pliocene AMOC strengthening is reduced transport of freshwater from the Arctic into the North Atlantic, enhanced by a decrease of surface freshwater flux into the high‐latitude North Atlantic.
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series Geophysical Research Letters
spelling doaj-art-bb2684bc1ab9429bbd2f34f38b64dca12025-08-20T03:09:49ZengWileyGeophysical Research Letters0094-82761944-80072025-02-01524n/an/a10.1029/2024GL113118Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)Julia E. Weiffenbach0Wing‐Le Chan1Ayako Abe‐Ouchi2Anna S. von derHeydt3Institute for Marine and Atmospheric Research Utrecht Department of Physics Utrecht University Utrecht The NetherlandsAtmosphere and Ocean Research Institute University of Tokyo Kashiwa JapanAtmosphere and Ocean Research Institute University of Tokyo Kashiwa JapanInstitute for Marine and Atmospheric Research Utrecht Department of Physics Utrecht University Utrecht The NetherlandsAbstract We use the coupled atmosphere‐ocean model MIROC4m to investigate the effect of mid‐Pliocene boundary conditions on the Atlantic Meridional Overturning Circulation (AMOC), studying the impact of increased CO2, reduced ice sheets and altered orography and vegetation. We find that a higher CO2 concentration and smaller ice sheets both weaken the AMOC with respect to the pre‐industrial. The stronger mid‐Pliocene AMOC is therefore a consequence of mid‐Pliocene orography and vegetation, where the closed Arctic gateways are responsible for approximately 80% of the AMOC strengthening. The main mechanism for mid‐Pliocene AMOC strengthening is reduced transport of freshwater from the Arctic into the North Atlantic, enhanced by a decrease of surface freshwater flux into the high‐latitude North Atlantic.https://doi.org/10.1029/2024GL113118plioceneglobal climate modelatlantic meridional overturning circulationarctic gatewaysnorth atlantic
spellingShingle Julia E. Weiffenbach
Wing‐Le Chan
Ayako Abe‐Ouchi
Anna S. von derHeydt
Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)
Geophysical Research Letters
pliocene
global climate model
atlantic meridional overturning circulation
arctic gateways
north atlantic
title Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)
title_full Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)
title_fullStr Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)
title_full_unstemmed Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)
title_short Impact of Mid‐Pliocene Boundary Conditions on the Atlantic Meridional Overturning Circulation (AMOC)
title_sort impact of mid pliocene boundary conditions on the atlantic meridional overturning circulation amoc
topic pliocene
global climate model
atlantic meridional overturning circulation
arctic gateways
north atlantic
url https://doi.org/10.1029/2024GL113118
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AT ayakoabeouchi impactofmidplioceneboundaryconditionsontheatlanticmeridionaloverturningcirculationamoc
AT annasvonderheydt impactofmidplioceneboundaryconditionsontheatlanticmeridionaloverturningcirculationamoc