Simulating the mid-Holocene, last interglacial and mid-Pliocene climate with EC-Earth3-LR

Abstract

Abstract. As global warming is proceeding due to rising greenhouse gas concentrations, the Earth system moves towards climate states that challenge adaptation. Past Earth system states are offering possible modelling systems for the global warming of the coming decades. These include the climate of the mid-Pliocene (∼ 3 Ma), the last interglacial (∼ 129–116 ka) and the mid-Holocene (∼ 6 ka). The simulations for these past warm periods are the key experiments in the Paleoclimate Model Intercomparison Project (PMIP) phase 4, contributing to phase 6 of the Coupled Model Intercomparison Project (CMIP6). Paleoclimate modelling has long been regarded as a robust out-of-sample test bed of the climate models used to project future climate changes. Here, we document the model setup for PMIP4 experiments with EC-Earth3-LR and present the large-scale features from the simulations for the mid-Holocene, the last interglacial and the mid-Pliocene. Using the pre-industrial climate as a reference state, we show global temperature changes, large-scale Hadley circulation and Walker circulation, polar warming, global monsoons and the climate variability modes – El Niño–Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). EC-Earth3-LR simulates reasonable climate responses during past warm periods, as shown in the other PMIP4-CMIP6 model ensemble. The systematic comparison of these climate changes in past three warm periods in an individual model demonstrates the model's ability to capture the climate response under different climate forcings, providing potential implications for confidence in future projections with the EC-Earth model.

EC‐Earth Simulations Reveal Enhanced Inter‐Hemispheric Thermal Contrast During the Last Interglacial Further Intensified the Indian Monsoon

“…Through model intercomparisons, EC-Earth3-LR simulates a positive temperature bias in the Arctic region during LIG, hence a weaker boreal latitudinal temperature gradient compared to other PMIP4 model simulations, while the simulated southern hemisphere latitudinal temperature gradient is close to the PMIP4 ensemble mean (Otto-Bliesner et al, 2021). Negative surface temperature responses in the Indian Monsoon region are similar in the range between EC-Earth3-LR and ensemble mean (Otto-Bliesner et al, 2021;Zhang et al, 2021). Global monsoons in the EC-Earth3-LR simulations have also been evaluated in Zhang et al (2021) for mid-Holocene, LIG and mid-Pliocene.…”

“…Negative surface temperature responses in the Indian Monsoon region are similar in the range between EC-Earth3-LR and ensemble mean (Otto-Bliesner et al, 2021;Zhang et al, 2021). Global monsoons in the EC-Earth3-LR simulations have also been evaluated in Zhang et al (2021) for mid-Holocene, LIG and mid-Pliocene. Changes relative to pre-industrial simulations have shown that the model changes in monsoon area and intensity in all three warming climates in relation to the forcing and the pre-industrial simulation.…”

Past terrestrial hydroclimate driven by Earth System Feedbacks

“…We use a suite of model simulations conducted as part of the 2nd Pliocene Model Intercomparison Project (PlioMIP2) (35,(69)(70)(71)(72)(73)(74)(75). Boundary conditions are derived from the PRISM4 dataset (32).…”

Calendar effects on surface air temperature and precipitation based on model-ensemble equilibrium and transient simulations from PMIP4 and PACMEDY

“…So far, there are a variety of previous studies aiming to examine the simulated climate of the mid-Holocene and Last Interglacial. Due to the Earth's orbital parameter anomalies with respect to the present, the MH and LIG receive more insolation in boreal summer and less in boreal winter over the Northern Hemisphere, leading to a larger seasonal temperature contrast in the two time periods (Kukla et al, 2002;Shi and Lohmann, 2016;Shi et al, 2020;Zhang et al, 2021;Kageyama et al, 2021b;Herold et al, 2012;Nikolova et al, 2013). Such an effect is much more profound in the LIG than in the MH (Lunt et al, 2013;Pfeiffer and Lohmann, 2016).…”