Economic evaluation of adaptation interventions to reduce the adverse health effects of temperature extremes: a systematic review

Abstract Background Extreme heat and cold cause substantial morbidity, productivity, mortality, and wellbeing losses, yet economic evidence on adaptation remains fragmented. This systematic review synthesised full economic evaluations of adaptation interventions addressing the adverse health impacts of extreme temperatures. It aimed to identify the economic evaluation methods used and examine whether recurring patterns in the direction and consistency of reported performance emerge across interventions. Methods Web of Science, Scopus, MEDLINE (via PubMed), and RePEc (via EconBiz) databases were searched on 19 July 2026 for peer-reviewed journal articles published in English from 1 January 2010 onwards. Eligible studies assessed adaptation to heat or cold and reported incremental costs and outcomes. Data were extracted using a standardised form and synthesised narratively by intervention type. Risk of bias and quality were assessed using standard instruments. Results Seventeen studies were included. Heat-health warning systems showed benefit-cost ratios generally exceeding one (from ~ 2–3 for morbidity-only estimates to two-, three-, and four-digit ratios for mortality-based estimates). Mechanical cooling and air conditioning interventions also generally produced favourable results, although some findings were sensitive to assumptions regarding discounting, targeting, and cost scope. Urban greening and reflective or vegetated surfaces yielded mixed results, with four out of six studies reporting at least one economically unfavourable central estimate, while workplace adaptation policies showed benefit-cost ratios below one in the first years after implementation but above one over longer time horizons. The only study evaluating an extreme cold intervention reported unfavourable results at baseline. When mortality avoidance was included and monetised, it accounted for the largest share of estimated benefits. Conclusions Heat-health warning systems showed the most consistently favourable economic performance, followed by mechanical cooling interventions, whereas urban greening, reflective surfaces and workplace adaptations appeared favourable only in certain contexts. These conclusions are based largely on model- and simulation-based evaluations, with few studies employing causal identification designs. Economic performance depended on methodological choices and study context. This heterogeneity is inherent to the evidence base rather than a methodological shortcoming. Future research should employ more robust causal inference methods and enhance the comparability of economic evaluations to provide stronger evidence for adaptation policy.