What (de)stabilizes the AMOC in the 21st century? Insights from high-resolution climate model simulations
Oliver Mehling, University of Utrecht
06/02/2026 – 11:30
CNR-ISAC, Bologna meeting room and ONLINE
Abstract
It has long been hypothesized that the Atlantic Meridional Overturning Circulation (AMOC) can have two competing stable states, but it remains an open question if an AMOC tipping point could be crossed under global warming. One reason for this uncertainty is an incomplete understanding of processes destabilizing (or stabilizing) the AMOC under global warming, especially at eddy-permitting or eddy-resolving ocean resolutions.
In this talk, I will share some recent insights from high-resolution model simulations into two processes relevant for AMOC stability under global warming: increasing Greenland melt (destabilizing) and the northward shift of AMOC source regions (potentially stabilizing). We analyze these processes in a 1/10° ocean model and a 1/4° coupled climate model, respectively. We use two frameworks that relate AMOC changes to a few large-scale diagnostics such as density gradients and stratification or to regional contributions to dense-water formation. Overall, this combination of different mechanisms paints a complex picture of 21st-century AMOC changes, and our simulations so far do not suggest a strong impact of model resolution.
Bio
Oliver Mehling is a postdoctoral researcher at Utrecht University, where he works in the group of Prof. Henk Dijkstra. He studied Physics in Freiburg and Heidelberg (Germany) and graduated with a PhD (also about the AMOC) from Politecnico di Torino in January 2025. His research spans various aspects of the AMOC (variability, mechanisms of future changes, tipping dynamics, and climate impacts of AMOC changes), which he studies using climate models of various complexity.