Modelling climate tipping-point cascade: the interlinked evolution of ocean circulation and Greenland ice sheet

Diplôme Master Modelling climate tipping-point cascade: the interlinked evolution of ocean circulation and Greenland ice sheet eng 2026-04-17 author Lucet Thomas Vitalis 409361 director Brunetti Maura 0000-0001-8199-223X 649277 Serv com physique appliquée (FIGCO) director Kasparian Jérôme 0000-0003-2398-3882 662563 Serv com physique appliquée (FIGCO) director Moinat Laure Agnès Liliane 0000-0002-4831-731X 889095 Serv com physique appliquée (FIGCO) 62 <p>Anthropogenic climate change threatens to destabilize several key components of the Earth's climate system, known as tipping elements, which may cross critical thresholds and undergo abrupt, potentially irreversible transitions. Among these, the Atlantic Meridional Overturning Circulation (AMOC) and the Greenland Ice Sheet (GrIS) represent two of the most vulnerable and interconnected subsystems. This thesis investigates the susceptibility of both elements to tipping behavior within an asynchronously coupled climate modeling framework, and examines the extent to which their interactions may trigger cascading tipping-point events at the global scale. The methodological approach relies on the MIT General Circulation Model (MITgcm), asynchronously coupled to the BIOME4 vegetation model and the MITgcmIS ice sheet model. Two slightly different control configurations were defined at a fixed atmospheric CO₂ concentration of 360 ppm, corresponding to a climate state approximately +2°C warmer than preindustrial levels in our simulations. Starting from these stable states, destabilization protocols were applied as instantaneous perturbations representing different levels of GrIS melt as well as freshwater hosing experiments in the North Atlantic. Results show that the AMOC behaves as a sensitive and influential component of the climate system. Depending on the magnitude of imposed perturbations and the background state of the system, the AMOC can either exhibit resilience and recover toward its reference state, or undergo a tipping event characterized by a collapse of the overturning circulation. When tipping occurs, the reduction in northward oceanic heat transport induces pronounced cooling across the Northern Hemisphere — particularly over Greenland, the North Atlantic, and Europe, with anomalies reaching up to −6°C. In response, the Southern Hemisphere, and Antarctica in particular, experiences substantial warming of +6 to +8°C, consistent with the bipolar thermal seesaw mechanism.</p> Dewey 500.2 Dewey 333.7-333.9 Master Universitaire des Sciences de l’Environnement (MUSE) 18 Institut des sciences de l'environnement 0DB 35 Groupe de physique appliquée 135 false 803 Groupe Kasparian 938 ISE Pôle Sciences 943 ISE Climat b7aa3b99-84ba-4ac6-a555-0ba4e4a5fe27 Master thesis Restricted Memoire_Lucet_MUSE.pdf 17477815 application/pdf 92c006026526ea0bcd9b246b81e07d6bf1029f52f961efb74f552248c5c692fc restrictedAccess Centres et instituts / Institut des sciences de l'environnement Faculté des sciences / Section de physique / Groupe de physique appliquée

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Modelling climate tipping-point cascade: the interlinked evolution of ocean circulation and Greenland ice sheet				2026	17	2

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Lucet, Thomas Vitalis

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