Estimating the effects of temperature on mortality and hospitalisations under RCP2.6 and RCP8.5 scenarios in the short- and long-term by region in Chile: a population-based, modelling study.

Background: In a warming world, it is generally accepted that increasing temperatures affect human health. In many regions of the world, however, these effects are poorly understood. To address this issue in Chile, we estimated the potential change in all-cause and cardiovascular and temperature-related (CVT) mortality and hospitalisations associated with four different climate scenarios by region.

Methods: Using Chilean health data and ERA5 reanalysis data, we modelled the relationship between historical health outcomes and monthly temperature indices using Generalised Additive Models. After evaluating the models' predictive performance, we used them to estimate changes in health outcomes associated with bias-adjusted climate projections representing four scenarios: short-term (2031-2060) and long-term (2061-2090) periods under both Representative Concentration Pathways (RCPs) 2.6 and 8.5.

Findings: Scenario-based health outcomes show clear north-south variations. Compared to historical levels, all-cause mortality increases by ∼1.5% in northern regions but decreases by ∼1% in southern regions across scenarios. CVT mortality decreases (0.2-3.6%), especially in the south; however, Arica and Tarapacá in the north show sharp increases (up to 30%) under warmer scenarios. Conversely, all-cause and CVT hospitalisations increase in northern/central regions (higher in summer, lower in winter), while southern/austral regions show slight decreases (∼1%).

Interpretation: These findings highlight the need for region-specific analyses and public health strategies in Chile. Northern regions might require plans that reduce the risk of heat-related mortality and morbidity, while southern regions might adjust healthcare services because of potential shifts in healthcare needs.

Funding: National Agency for Research and Development, Chile and University College London, UK.