Climate change-induced economic impact assessment by parameterizing spatially heterogeneous CO2 distribution

The spatially heterogeneous distribution of CO2 concentrations is an uncertain factor in the assessment of climate change impact. We developed and calibrated a simple climate module to project regional temperature increases using atmospheric simulation output data from the Coupled Model Inter-comparison Project Phase 6 (CMIP6). We compared the differences in regional atmospheric temperature changes arising from spatially homogeneous and heterogeneous distributions of CO2 and assessed economic loss. The results indicated that spatially heterogeneous distribution of CO2 affected the projection of regional temperature increases, with faster temperature rises in industrially advanced regions. Compared with a homogeneous distribution, economic damage was aggravated in the Northern Hemisphere using a heterogeneous distribution, especially in middle-latitude regions. China saw increases in economic damage of 0.030%, 0.007%, and 0.002% in 2100 under SSP5-RCP8.5, SSP2-RCP4.5, and SSP1-RCP2.6, respectively. This suggests that impact assessments that ignore spatially heterogeneous CO2 concentrations could lead to inaccurate estimates of climate damage. These findings indicate that it is necessary to parameterize the spatial distribution of CO2 in traditional climate change assessments. The results provide a more accurate estimation of regional temperature increases and climate change-induced economic damage to support policymaking for mitigation and adaptation.