Future temperature-related mortality in Latin American cities under climate change and population scenarios

In Latin America, climate change, urbanization, and an aging population are intensifying health risks from extreme temperatures. To accurately assess future temperature-related mortality impacts, evidence that integrates key demographic factors-such as the dynamics of population age composition, mortality rates, and population size-is essential.

We projected the impact of nonoptimal temperatures on all-age and age-specific mortality during 2045-2054 for 326 cities in Latin America. Our analysis combined city-level daily mortality counts, gridded temperature data, downscaled and bias-corrected temperature simulations, and demographic data. We projected temperature-mortality impacts under two climate change scenarios while also considering changing population size, age structure, and age-specific mortality rates.

By 2045-2054, the percentage of heat-attributable deaths under the most extreme temperature scenario will more than double from 0.87 % (95 % CI 0.77, 0.96) to 2.06 % (95% CI 1.80, 2.33), but cold-related mortality will decrease. Population growth and aging will exacerbate heat-related risks and offset reductions in cold-related deaths. For example, changes in population age structure will drive an increase in the heat-related mortality rate of 176% from baseline for a moderate temperature scenario.

Beyond temperature changes, demographic shifts-particularly population growth and aging-will significantly amplify mid-century temperature impacts on mortality, underscoring the need for targeted climate adaptation and public health strategies.