The impact of population ageing on temperature-related mortality projections in the Czech Republic

Climate change and population ageing are jointly reshaping temperature-related mortality patterns in Europe; however, their combined effects remain insufficiently quantified on the national scale. In the Czech Republic, cold-related mortality has historically exceeded heat-related mortality, but this pattern is expected to shift under future climate and demographic transitions. Here, we projected future heat- and cold-attributable mortality under both climate-only and population ageing scenarios. We estimated age-specific (<75 and ≥75 years) temperature–mortality associations for all 14 NUTS-3 regions using a three-stage time-series modelling framework and combined them with high-resolution EURO-CORDEX climate projections and Shared Socioeconomic Pathway population scenarios under RCP4.5/SSP2 and RCP8.5/SSP5. Heat- and cold-attributable mortalities were projected across four future periods. Heat-attributable mortality increases substantially, rising from 2 deaths historically to 20 deaths by the 2090s under RCP8.5/SSP5. Cold-attributable mortality declines under climate-only scenarios but increases markedly when population ageing is included, reaching 105 deaths by the 2090s and reversing climate-driven reductions. The combined net temperature-related mortality burden increased from 82 deaths in the historical period to 124 under population ageing scenarios, with ageing contributing to 71 additional deaths by the 2070s. Our findings demonstrate that population ageing outweighs climate-driven changes in shaping future temperature-related mortality in the Czech Republic. Ignoring demographic changes leads to a substantial underestimation of future health burdens. Integrating age-specific population projections into climate-health assessments is essential for adaptation planning and public health preparedness in ageing societies.