Global climate damage in 2℃ and 1.5℃ scenarios based on BCC_SESM model in IAM framework

The quantitative functions for climate damages provide theoretical ground for the cost-benefit analysis in climate change economics,and they are also critical for linking climate module with economic module in the Integrated Assessment Models(IAMs).Nevertheless,it is necessary for IAMs to update sectoral climate impacts in order to catch up the advance in climate change studies.This study updates the sectoral climate damage function at global scale from climate Framework for Uncertainty,Negotiation and Distribution(FUND)model and develops the aggregate climate damage function in a bottom-up fashion.Besides conventional sectors such as agriculture,forestry,water resources,energy consumption and ecosystems,this study expands climate disaster types,assesses human health impacts caused by various air pollutants,and updates coastal damage by sea level rise.The Beijing Climate Center Simple Earth System Model(BCC_SESM)is used to project climate system based on Business-as-Usual(BAU)scenario,and the 2℃ and 1.5℃ scenarios based on RCPs and SSP2 databases.Sectoral results show that the agricultural sector is projected to suffer 63% of the total damage,followed by water resources(16%)and human health(12%)sectors in 2100.The regression results indicate that the aggregate climate damage function is in positive quadratic form for zero discounting.Under BAU scenario,the aggregate climate damage is projected to be 517.7 trillion USD during 2011-2100.Compared to that,the 2℃ and 1.5℃ scenarios are projected to respectively reduce climate damages by 215.6 trillion USD(approximately 41.6%)and 263.5 trillion USD(50.9%)in 2011-2100.