Temperature-related mortality in nine Latin American countries under climate change and population scenarios

Climate change and an aging population are converging challenges rapidly accelerating the risk of extreme temperatures for older adults in Latin America. Older adults are especially vulnerable to health impacts from extreme temperatures and in Latin America the proportion of adults aged 65+ years is expected to double by 2050. However, existing projections of temperature-related mortality in Latin America do not incorporate expected population aging, likely severely underestimating future deaths. We estimated temperature-related deaths from 2045-2054 in all cities in nine Latin American countries under RCP2.6 and RCP8.5 climate scenarios, given expected changes in population age distribution.[¤]METHOD[|]Across 326 Latin American cities in nine countries, we compiled current daily mortality records, dynamic downscaled simulations of city-level daily temperatures at a historical baseline (2002-2015), RCP2.6, and RCP8.5 emissions scenarios (2045-2054), along with city-level U.N. projections of population age distribution and mortality rates in 2050. We used city-specific temperature-mortality curves derived at baseline to project heat- and cold-attributable deaths in 2050 given projected changes in temperatures, population age distribution, and mortality rates.[¤]RESULTS[|]At baseline across all 326 cities, 0.60% of all-cause deaths were attributable to ambient heat. By mid-century, heat-attributable deaths increased to 1.55% under RCP2.6 and 1.84% under RCP8.5, an increase of 2.6x and 3.1x respectively. These projected changes were highly spatially variable (RCP8.5 city-specific heat-attributable deaths, 10th percentile: 0%, 90th percentile 4.75%). Deaths attributable to cold decreased from 4.82% at baseline to 4.72% under RCP2.6 and 3.82% under RCP8.5.[¤]CONCLUSIONS[|]Climate change and rapid populating aging will dramatically increase heat-attributable mortality by mid-21st century. Deaths averted from less intense cold temperatures will be comparatively small. Policymakers must urgently work to reduce greenhouse gas emissions and enact public health policies to protect the population, particularly older adults, from the health impacts of extreme heat.