Simulation of the Early Eocene Climate and the Implications for Climate Sensitivity

November 21, 2024

Jiang Zhu

Hosted by Maria Rugenstein

Abstract

Simulating the warmth and equability of the early Eocene climate (~50 million years ago) has posed a persistent challenge in paleoclimate modeling, commonly known as the equable climate problem. The inability of climate models to accurately reproduce the past warm climate raises doubts about their capability to predict the future anthropogenic warming. In this talk, I will summarize the early Eocene simulations conducted using the latest generations of Community Earth System Model (CESM). The results suggest that the CESM models can capture the large-scale features of the early Eocene global mean surface temperature (GMST) and the equator-to-pole gradient. Notably, the simulated GMSTs depend heavily on parameterizations of atmospheric radiation, convection, and clouds. Model-data discrepancies persist at regional and seasonal scales and are further explored in a coupled simulation with unprecedented high resolution. Throughout the talk, I will illustrate how the early Eocene climate serves as a valuable benchmark for assessing the climate sensitivity of models. I will also demonstrate how paleoclimate simulations can contribute to the improvement of climate models.