<div>
<div>
<p><span data-contrast="auto">The climate relaxes toward a steady state under a permanent inhomogeneous forcing from solar radiation and dissipative mechanisms. As a highly nonlinear system, the Earth&#8217;s climate can exhibit multiple steady states at a given forcing. Multistability has been observed in numerical models of different complexities, including fully coupled general circulation models with an aquaplanet configuration (Ragon et al. 2022), and we show here multistability also applies for the Earth in deep time. </span></p>
<p><span data-contrast="auto">We use the MIT general circulation model in a coupled atmosphere-ocean-sea ice-land configuration to perform simulations at a constant forcing </span><em><span data-contrast="auto">i.e.</span></em><span data-contrast="auto">, fixed solar constant and atmospheric partial pressure of CO</span><span data-contrast="auto">2</span><span data-contrast="auto">. We let the system relax for thousands of years</span><span data-contrast="auto">,</span><span data-contrast="auto"> which is the typical timescale of ocean dynamics. Considering the paleogeography of the Permian-Triassic reconstructed after PANALESIS (V&#233;rard 2015), we find multiple competing steady states, representing alternative potential climates for that period.</span></p>
<p><span data-contrast="auto">Then, we construct the corresponding bifurcation diagram by varying the atmospheric CO</span><span data-contrast="auto">2</span><span data-contrast="auto"> content. This allows us to identify the stability range of each steady state, the position of tipping points and the required conditions for the system to shift from one state to another, which may help to understand the climatic oscillations observed, </span><em><span data-contrast="auto">e.g.</span></em><span data-contrast="auto">, during the Early Triassic.</span></p>
<p><span data-contrast="auto">References</span></p>
<p><span data-contrast="auto">Ragon C., Lembo V., Lucarini V., V&#233;rard C., Kasparian J. & Brunetti M., Robustness of competing climatic states. Journal of Climate, 35, 2769-2784. (2022)</span></p>
<p><span data-contrast="auto">V&#233;rard C., PANALESIS: Towards global synthetic pal&#230;ogeographies using integration and coupling of manifold models. Geological Magazine, 156, 320-330. (2015)</span><span data-ccp-props="{">&#160;</span></p>
</div>
</div>