Heat stress, labor productivity, and economic impacts: analysis of climate change impacts using two-way coupled modeling

Climate change affects various fundamental human activities, and understanding the consequences of its impacts is essential. Among them, heat stress considerably affects economic conditions. Furthermore, when analyzing the socioeconomic impacts of climate change, both socioeconomic and climate systems must be considered simultaneously, though such studies are scarce. This study aimed to evaluate the socioeconomic impacts of changes in labor productivity due to heat stress (measured by wet bulb globe temperature) under various climate change scenarios through a new modeling framework that coupled a computable general equilibrium model and an Earth system model of intermediate complexity to realize the interactions between the two systems through the relationship between heat stress and labor productivity. Results indicated that labor productivity declined as climate change progressed (particularly in hot and humid regions), driving a gradual decline in total global gross domestic product (GDP). Although regional GDP largely decreased where labor productivity considerably declined, it slightly increased in some areas because of a comparative advantage brought about by the difference in the impact on labor productivity by region. Consequently, carbon dioxide (CO2) emissions and concentrations and the resulting temperature were slightly reduced when examining the impact of climate change on labor productivity. These tendencies were similar in both business-as-usual and climate change mitigation scenarios, but the overall impacts were smaller under the latter. There was a limited impact on CO2 emissions, CO2 concentrations, and temperature via integrated socioeconomic and climate systems. However, this study focused on only a single channel of the various interactions between the two systems. For a more complete evaluation of the impacts of climate change, further development of the integrated model is required.