Appears in collection : 2026 - T2 - WS2 - Instabilities and transitions in geophysical flows

While AMOC stability is traditionally viewed through simple box models, these models exhibit a diverse range of behaviors dictated by the background climate. These can be classified into two regimes: abrupt tipping points (saddle-node bifurcations) and millennial-scale oscillations (Hopf bifurcations). This presentation reviews the evolution of conceptual models of the AMOC, identifying how mechanisms like advection, diffusion, sea ice, and stratification drive these distinct behaviors. We introduce a minimal, physically based framework that maps the system's full bifurcation space against global temperature and freshwater forcing. This approach offers a unified perspective on AMOC dynamics, demonstrating that warm, present-day climates are prone to saddle-node collapses, whereas cold, glacial-type climates naturally favor limit-cycle oscillations.