Collapse of the AMOC in a strongly eddying global ocean model

Grant Agreement Number: 101137601 Collapse of the AMOC in a strongly eddying global ocean model René van Westen, Michael Kliphuis and Henk Dijkstra TAOC ClimTip | Quantifying Climate Tipping Points and Their Impacts AMOC Model Hierarchy 2 ClimTip | Quantifying Climate Tipping Points and Their Impacts AMOC collapse in CESM (CMIP5) 3 Black: Forward Red: Backward Van Westen & Dijkstra (2023) Freshwater Forcing FH Ocean/Atmosphere model horizontal resolution: 10 / 20 Rate: 0.3 mSv/year ClimTip | Quantifying Climate Tipping Points and Their Impacts Does the AMOC also have a multi-stable regime in a model where ocean eddies are explicitly represented? 4 - Better representation of heat and freshwater transport - More realistic representation of boundary currents Horizontal resolution: 1.00 Horizontal resolution: 0.10 ClimTip | Quantifying Climate Tipping Points and Their Impacts Global ocean model (POP) 5 HR-POP: Horizontal resolution: 0.10 - Background forcing: CORE (seasonal mean) - Freshwater forcing FH: 20-500N, Rate: 0.3 mSv/yr LR-POP:Horizontal resolution: 1.00 ClimTip | Quantifying Climate Tipping Points and Their Impacts AMOC Collapse 6 - Collapse onset: FH = 0.126 (model year 420) - Minimum FovS just before onset ClimTip | Quantifying Climate Tipping Points and Their Impacts AMOC Patterns 7 - Collapsed state: weak overturning ~ 5 Sv ClimTip | Quantifying Climate Tipping Points and Their Impacts Upwelling Pathways 8 Caption Following: Baker et al. (2025) ClimTip | Quantifying Climate Tipping Points and Their Impacts Impacts of AMOC Collapse 9 Difference: model years 551-560 and 1-50