Conference Agenda

Extreme heat is a growing public health risk, yet evidence on heat-related morbidity remains fragmented across countries and difficult to compare because studies rely on different data sources, exposure metrics, and empirical designs. We compile harmonized daily hospitalization microdata from eight Latin American countries covering more than 200 million people during 2015--2019 and merge these records with high-resolution ERA5-Land reanalysis weather data. Using a flexible temperature-bin dose--response framework with high-dimensional fixed effects that exploits within-municipality deviations from typical seasonal temperature patterns, we estimate pooled and country-specific impacts of extreme heat on hospital admissions. We document a striking convergence in aggregate morbidity responses across countries: days in the hottest temperature bins generate large increases in hospitalizations of similar magnitude despite wide differences in climate, income, and health systems. Cause-specific analyses show that extreme heat disproportionately increases admissions for communicable diseases and injuries, while non-communicable and maternal/neonatal admissions do not rise on average. In contrast to cross-country convergence, vulnerability within countries is sharply divergent. Heat-related morbidity increases steeply in low-development municipalities and is close to zero in the highest-HDI areas, and effects follow an inverted-U relationship with urbanization, peaking in intermediate-density municipalities. Together, the results indicate that while heat--health relationships are broadly similar across countries, climate--health vulnerability is shaped primarily by subnational inequalities in adaptive capacity and the built environment, with implications for targeting heat-health preparedness and infrastructure investments.