Developing the coupled climate model ACCESS-ESM1.5 for the early Eocene

We are currently developing the Australian community climate model ACCESS-ESM1.5 for deep time paleoclimate simulations. We are currently targeting the early Eocene (~55 Ma) and the Miocene climate optimum (~15 Ma); two warm intervals with high CO2 concentrations and strong polar amplification. The major challenge in adapting this model is to implement extensive changes to surface boundary conditions, including topography, vegetation, river runoff and ice sheets. The model has never previously been run outside of modern boundary conditions. We have developed new prototype simulations for each time period, and will present preliminary results for the Eocene and Miocene using ACCESS-ESM1.5. These simulations will be developed in parallel with simulations using the GFDL CM2.1 coupled climate model, which has been established as an efficient tool for reaching equilibrium paleoclimate scenarios.