Regional Emissions Air-quality Climate Health assessment framework

The Regional Emissions Air-quality Climate Health (REACH) assessment framework combines an energy-economic model, an emission inventory module, an atmospheric chemistry transport model, and a health effects evaluation module. It simulates the complex and non-linear relationship between economic activity, energy use, CO2 emissions, air quality, and health impact, capturing the comprehensive impact of energy, economic and environmental policies at the provincial level. The core of the REACH assessment framework is the China Regional Energy Model (C-REM) and an atmospheric chemistry model. By connecting the C-REM and an atmospheric chemistry model, the REACH framework can estimate impacts of air quality changes in different regions under different GHG emissions reduction scenarios in a consistent way, thus supporting research on policy synergies between climate change and air pollution.


CGEM-Hector model

The CGEM-Hector model is constructed by coupling the China in Global Energy Model (C-GEM, a global recursive dynamic computable general equilibrium model) and the Hector model (a simple climate model). In the CGEM-Hector model, C-GEM simulates the flow of products and factors in the market through the general equilibrium theory, and the economic activities can generate greenhouse gases emissions. The anthropogenic GHG emissions can drive the simple climate model Hector to simulate key climate variables. These climate variables are inputs of the climate damage assessment module, and the damage functions can transfer the climate variables into economic variables, then return the economic variables to socio-economic module. This feedback mechanism will cause a new equilibrium state in the C-GEM model, driving it to generate GHG emissions in the next period. These GHG emissions are the input of the Hector model, thus forming a two-way dynamic coupling route.


Figure 1.  Structure of the CGEM-Hector model

The introduction and application of the CGEM-Hector model can be found in the published document (WANG T, TENG F, ZHANG X. Assessing global and national economic losses from climate change: A study based on CGEM-IAM in china [J]. Climate change economics, 2020: 2041003.). The model also supported the National Key R&D Program project "Development and improvement of integrated assessment model for climate change impact assessment" (2016-2021).


CGEM-CESM model

The CGEM-CESM model is constructed by coupling the China in Global Energy Model (C-GEM, a global recursive dynamic computable general equilibrium model) and the Community Earth System Model (an earth system model). In the CGEM-CESM model, C-GEM simulates the flow of products and factors in the market through the general equilibrium theory, and the economic activities can generate greenhouse gases emissions. The GHG emissions can drive the Earth system model CESM to simulate gridded climate variables (temperature, precipitation, humidity, etc.). These climate variables are inputs to the climate damage assessment module. The damage assessment module contains a series of gridded damage functions, which can translate the generated climate variables into changes in economic variables. The regional aggregated economic variables will be returned to the C-GEM model to drive it to simulate GHG emissions in the next period. These GHG emissions are the input of the CESM model, thus forming a two-way dynamic coupling route.


Figure 1.  Structure of the CGEM-CESM model

The introduction and application of the CGEM-CESM model can be found in the published document (Teng Fei, Wang Tianpeng, Guo Jiangwen. Carbon neutrality targets and climate risk. China-UK Climate Risk Project Phase III Reports, 2021.). The model also supported the National Key R&D Program project "Development and improvement of integrated assessment model for climate change impact assessment" (2016-2021) and the China-UK climate cooperation project “China-UK Cooperation on Climate Change Risk Assessment”.