Integrating heat-related mortality into IAMs: A comparative assessment of modelling frameworks

Non-optimal temperatures pose a significant mortality risk that keeps worsening under a warming world. The lack of global mortality and sociodemographic data poses a major challenge in developing models suitable for incorporation into IAMs to project the future burden under various climate and socioeconomic scenarios. This research analysed the state-of-the-art global models developed by the epidemiological and econometric communities that quantify mortality from heat. It provided a comparative analyses of the historical mortality estimations from each model and an overview of the different advantages and limitations for IAMs. After selecting the most suitable model for its ability to endogenize adaptation to heat, it was coupled to the process-based IMAGE model. The model projected future mortality across four scenarios that illustrate the differentiated effects of warming and adaptation levels, reflecting how rising incomes can serve as a protective measure against heat risk and the counteractive effect of rising temperatures. Although there is no definitive best model, integrating a suitable option into an IAM represents a crucial first step toward developing a more integrated assessment of future health impacts.