Heat-related mortality in Europe during the summer of 2022

The study investigates the mortality burden attributable to extreme summer heat in Europe during 2022, the hottest season on record for the continent. Motivated by the substantial mortality observed during the 2003 heatwave and subsequent implementation of heat prevention plans, the research aims to quantify sex- and age-specific heat-related deaths across Europe in 2022 and place these findings within the context of recent climatic warming and past extreme summers. The purpose is to inform public health preparedness and adaptation strategies by estimating the magnitude, distribution, and demographic patterns of heat-attributable mortality.

The paper situates its work within evidence that global and European temperatures have risen due to anthropogenic greenhouse gas emissions, with Europe identified as a climate change hotspot experiencing faster warming than the global average. Prior research shows heat waves produce substantial excess mortality, notably the 2003 European heatwave with over 70,000 excess deaths, prompting the development of heat-health prevention plans. Evidence on the effectiveness of these plans remains limited. Studies highlight higher vulnerability among older adults, women, socially isolated and socioeconomically disadvantaged groups, and those with preexisting cardiovascular and respiratory conditions. Previous analyses have reported declining heat-related risks in some settings, yet accelerated warming and increases in heatwave frequency/intensity suggest growing health impacts without further adaptation. The authors compare 2022 to 2003 while noting methodological differences: earlier estimates relied on excess mortality across fewer countries, whereas this study uses epidemiological attribution models across 35 countries.

Data sources: Weekly counts of all-cause mortality (by sex and age groups where available) were obtained from Eurostat and complemented with national statistical agencies as needed, covering January 2015 to November 2022 for 823 contiguous regions in 35 European countries (over 543 million people; 45,184,044 death counts). Temperature data were weekly regional averages of daily mean 2-m temperatures derived from ERA5-Land reanalysis. Population denominators came from Eurostat regional estimates. Modeling approach: A two-stage epidemiological framework was used. Stage 1 applied quasi-Poisson time-series regressions to each region to estimate temperature–lag–mortality associations using weekly data. Models included an intercept; a natural cubic spline of time with 8 degrees of freedom per year to control for seasonal/long-term trends; and a cross-basis for temperature with lags 0–3 weeks. The exposure–response function was modeled with a natural cubic spline with internal knots at the 10th, 50th, and 90th percentiles of region-specific weekly temperatures. Models were calibrated using January 2015–December 2019 to avoid pandemic-era effects and were fitted separately by sex and age groups. Stage 2 pooled region-specific coefficients via multivariate, multilevel meta-regression including country random effects and meta-predictors: region-specific mean temperature, temperature interquartile range, and percentage of population aged 80+ years. Best linear unbiased predictions from the meta-regression were used to derive region-specific minimum mortality temperatures (MMTs) and to transform observed 2015–2022 temperature and mortality time series into weekly and summer (weeks 22–35) heat-attributable deaths. Attribution and aggregation: Heat-related mortality was calculated for weeks with average temperatures above the region-specific MMT. National and European totals were obtained by aggregating regional estimates. Uncertainty was quantified using 1,000 Monte Carlo simulations to compute 95% confidence intervals. Heat-related mortality rates (per million) used annual regional populations. Temperature anomalies were computed as deviations from a 1991–2020 baseline mean annual temperature cycle modeled with a spline of day-of-year. Sensitivity analyses included re-calibrating models using 2015–2022 (including pandemic years) and testing different exposure–response specifications selected by AIC.

- Continental burden: An estimated 61,672 (95% CI: 37,643–86,807) heat-related deaths occurred in Europe during the 14-week summer period (30 May–4 September) of 2022; annual total estimate was similar (62,862; 95% CI: 37,935–88,780). - Temporal concentration: A major, pan-European heatwave occurred in week 29 (18–24 July), associated with 11,637 (95% CI: 7,639–15,970) deaths. Nearly two-thirds of summer heat-related deaths (38,881; 95% CI: 25,051–53,699) occurred during the 5-week period from 11 July to 14 August. - Country totals: Highest summer heat-related deaths were in Italy (18,010; 95% CI: 13,793–22,225), Spain (11,324; 95% CI: 7,908–14,880), Germany (8,173; 95% CI: 5,374–11,018), France (4,807; 95% CI: 1,739–8,123), the United Kingdom (3,469; 95% CI: 370–6,676), and Greece (3,092; 95% CI: 2,217–3,915). - Rates per million: Europe overall had 114 (95% CI: 69–160) heat-related deaths per million in summer 2022; women 145 (95% CI: 89–192), men 93 (95% CI: 63–120). Highest national rates were in Italy (295; 95% CI: 226–364), Greece (280; 95% CI: 201–355), Spain (237; 95% CI: 166–312), and Portugal (211; 95% CI: 162–255). - Sex and age patterns: Relative to population, women experienced 56% higher heat-related mortality than men overall. There were 63% more deaths in women (35,406; 95% CI: 21,576–46,634) than men (21,667; 95% CI: 14,684–27,998). Mortality increased steeply with age: 0–64 years: 4,822 (95% CI: 1,130–8,158), 16 per million (95% CI: 4–27); 65–79 years: 9,226 (95% CI: 665–17,382), 160 per million (95% CI: 12–302); 80+ years: 36,848 (95% CI: 27,591–45,509), 1,684 per million (95% CI: 1,261–2,080). Rates were higher in men for ages 0–64 (+41%) and 65–79 (+14%), and higher in women for age 80+ (+27%). - Geographic risk: Highest relative risks at high temperatures and highest mortality rates were concentrated in Mediterranean and parts of southeastern Europe, consistent with known latitudinal vulnerability patterns. - Climate context and trends: Summer 2022 was the warmest on record across the 35 countries (mean 20.30 °C = μ + 2.51σ), exceeding 2003. Compared to 2015–2021, 2022 had 25,561 more summer heat-related deaths. Warming since 2015 was associated with 18,547 additional summer heat-related deaths per +1 °C (35.3 per million per +1 °C). Projections assuming no further adaptation: average heat-related deaths per summer of ~68,116 by 2030, ~94,363 by 2040, and ~120,610 by 2050. - Sensitivity analyses: Including pandemic years in calibration (2015–2022) yielded slightly higher estimates for summer 2022 (68,476; 95% CI: 44,884–90,803) and annual 2022 (70,997; 95% CI: 46,612–94,777). Estimates were robust to different exposure–response specifications; meta-predictors explained significant spatial heterogeneity.

The findings demonstrate a substantial and demographically patterned mortality burden attributable to extreme summer heat during Europe’s hottest recorded season, confirming that current heat prevention and adaptation efforts were insufficient to prevent large-scale mortality. The results address the study aim by quantifying total, national, sex-, and age-specific burdens and identifying temporal windows of highest risk. The spatial pattern, with highest rates in Mediterranean countries, reflects underlying vulnerability rather than temperature anomalies alone, emphasizing the role of population sensitivity and structural factors. Comparisons to 2003 highlight both the methodological differences (excess mortality vs. epidemiological attribution) and the changing climate context: while 2003 was exceptional relative to preceding years, 2022 aligns with an accelerated warming trajectory, yet still produced very high mortality. The demonstrated scaling of deaths with temperature increases (+18,547 per +1 °C) underscores the urgency of enhancing surveillance, early warning, and adaptation measures, especially for the elderly and to reduce sex and socioeconomic disparities. Without stronger adaptation, the burden is projected to rise rapidly in coming decades.

This Europe-wide analysis quantifies over 61,000 heat-attributable deaths in summer 2022, with the greatest burdens in Mediterranean countries and among older adults, and higher population-adjusted mortality in women. The concentration of deaths during mid-July to mid-August and the strong association of deaths with incremental warming indicate that existing heat-health systems and adaptation plans require substantial reinforcement. Policymakers should prioritize improved heat surveillance, targeted protection for vulnerable groups, urban and housing adaptations, and broader climate mitigation to limit future health impacts. Future research should refine daily-resolution attribution to reduce bias, integrate cause-specific mortality, and incorporate granular sociodemographic data to better understand and address disparities.

- Temporal resolution: Weekly temperature and mortality data likely underestimate heat-related mortality compared with daily data and may not fully capture short lag structures of heat effects. - Data gaps: Sex- and age-specific data were unavailable for Germany, Ireland, and the United Kingdom (and all-age by sex unavailable for the UK), limiting disaggregated estimates in these countries. - Cause-of-death: Analyses used all-cause mortality due to lack of cause-specific data, constraining interpretation of mechanisms and subgroup differences. - Comparisons with 2003: Methodological differences (excess mortality vs. epidemiological attribution; country coverage) complicate direct comparisons of absolute burdens between 2003 and 2022. - Potential underestimation: Weekly models and aggregation may underestimate true burden; future work is needed to characterize biases and refine estimates.