A simple earth system model for C³IAM: based on BCC_CSM1.1 and CMIP5 simulations

Traditional complex climate system models used in natural sciences cannot match the integrated assessment models well due to differences in temporal and spatial resolutions and especially computational complexities. In this study, we develop a simple earth system model called Beijing Climate Center Simple Earth System Model (BCC_SESM), which is based on the complex BCC_CSM1.1 model and its CMIP5 simulation results as inputs. The basic and complete processes are considered in the BCC_SESM initiating from the carbon emission, including the carbon cycle processes in atmosphere–land–ocean, the radiation forcing and temperature changes. The emission-driven simulation results for historical and RCP8.5 scenarios are selected as the default datasets, and econometric regressions are applied to calibrate the parameters. Projection analysis and sensitive experiments with the BCC_SESM show that this model is parsimonious and robust enough to reproduce results of original complex climate system model. We also compare results of parameters and projection efficacy of different mid-lower emission scenarios simulations by applying this BCC_SESM. The results show that BCC_SESM is suitable for climate projections in the integrated assessment modeling, i.e., the C³IAM.