The Chinese Academy of Sciences Earth System Model version 2 (CAS-ESM2.0) has been developed independently by China in 2020. It consists of eight component models, namely the Atmospheric General Circulation Model developed in IAP (IAP-AGCM version 5), the LASG/IAP Climate system Ocean Model (LICOM version 2), the Beijing Normal University/IAP Common Land Model (CoLM), the Los Alamos Sea-Ice Model (CICE version 4), and the IAP Aerosol and Atmospheric Chemistry Model (IAP-AACM), using the CESM Coupler 7 (CPL7) to integrate all the components above. It also comprises the IAP Dynamic Global Vegetation Model (IAP-DGVM) and the IAP Land Biogeochemistry Model that are incorporated into the land model, and the IAP Ocean Biogeochemistry Model that is incorporated into the ocean model. In addition, a Solar-Terrestrial Space Environment Model, an Ice Sheet model, and a Solid Earth Model are also developed as independent component models, which are not coupled with the other eight component models during the current phase. CAS-ESM2.0 has participated in the Coupled Model Intercomparison Project phase 6 (CMIP6), and the model results were cited in the IPCC Sixth Assessment Report.
      There are two basic versions of CAS-ESM2.0 for different research objectives: A medium-resolution Earth system model which consists of all eight component models; and a high-resolution climate system model, which consists of three sub-systems, i.e. atmosphere, ocean (including sea ice), and land surface. The horizontal resolution of Earth system model version is 140 km for the atmospheric model, and 100 km for the ocean model, while the resolutions for the other component models are consistent with the atmospheric or ocean model. The horizontal resolution of climate system model version is 25 km for the atmospheric and land surface models, and 10 km for the ocean model.