Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions

Abstract During each of the dramatic global warmings that ended the Pleistocene ice ages, the Atlantic Meridional Overturning Circulation (AMOC) was disrupted. It is not clear whether this was a contributing cause or simply an effect of deglaciation. Here we show that in an ensemble of simulations w...

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Main Authors: Eric D. Galbraith, Timothy M. Merlis, Jaime B. Palter
Format: Article
Language:English
Published: Wiley 2016-08-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL069846
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author Eric D. Galbraith
Timothy M. Merlis
Jaime B. Palter
author_facet Eric D. Galbraith
Timothy M. Merlis
Jaime B. Palter
author_sort Eric D. Galbraith
collection DOAJ
description Abstract During each of the dramatic global warmings that ended the Pleistocene ice ages, the Atlantic Meridional Overturning Circulation (AMOC) was disrupted. It is not clear whether this was a contributing cause or simply an effect of deglaciation. Here we show that in an ensemble of simulations with a global climate model, AMOC disruption causes a consistent and sustained positive radiative imbalance of ~0.4 W m−2. The imbalance is accommodated by heat accumulation in the ocean interior, representing an overall planetary warming, subsequently released by deep convection in the North Atlantic when the AMOC resumes. The results suggest a means by which AMOC disruptions could have helped to tip the planet out of stable glaciated states. However, the fact that AMOC disruptions occurred during prior Heinrich Stadials without causing deglaciation shows that other factors, such as ice sheet dynamics, or controls on CO2, were also key for deglaciation.
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spelling doaj-art-bead1c396e324ba4839f110b958a3ac92025-08-20T02:31:39ZengWileyGeophysical Research Letters0094-82761944-80072016-08-0143158214822110.1002/2016GL069846Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptionsEric D. Galbraith0Timothy M. Merlis1Jaime B. Palter2ICREA Barcelona SpainAtmospheric and Oceanic Science McGill University Montreal Quebec CanadaAtmospheric and Oceanic Science McGill University Montreal Quebec CanadaAbstract During each of the dramatic global warmings that ended the Pleistocene ice ages, the Atlantic Meridional Overturning Circulation (AMOC) was disrupted. It is not clear whether this was a contributing cause or simply an effect of deglaciation. Here we show that in an ensemble of simulations with a global climate model, AMOC disruption causes a consistent and sustained positive radiative imbalance of ~0.4 W m−2. The imbalance is accommodated by heat accumulation in the ocean interior, representing an overall planetary warming, subsequently released by deep convection in the North Atlantic when the AMOC resumes. The results suggest a means by which AMOC disruptions could have helped to tip the planet out of stable glaciated states. However, the fact that AMOC disruptions occurred during prior Heinrich Stadials without causing deglaciation shows that other factors, such as ice sheet dynamics, or controls on CO2, were also key for deglaciation.https://doi.org/10.1002/2016GL069846radiative balanceclimate modeldeglaciationocean circulationice agesbipolar seesaw
spellingShingle Eric D. Galbraith
Timothy M. Merlis
Jaime B. Palter
Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions
Geophysical Research Letters
radiative balance
climate model
deglaciation
ocean circulation
ice ages
bipolar seesaw
title Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions
title_full Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions
title_fullStr Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions
title_full_unstemmed Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions
title_short Destabilization of glacial climate by the radiative impact of Atlantic Meridional Overturning Circulation disruptions
title_sort destabilization of glacial climate by the radiative impact of atlantic meridional overturning circulation disruptions
topic radiative balance
climate model
deglaciation
ocean circulation
ice ages
bipolar seesaw
url https://doi.org/10.1002/2016GL069846
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AT jaimebpalter destabilizationofglacialclimatebytheradiativeimpactofatlanticmeridionaloverturningcirculationdisruptions