Quantifying the contribution of climate change to heat-attributable mortality in Europe: Interfacing epidemiology and Extreme Event Attribution

Extreme Event Attribution (EEA) aims to answer the question of whether and to what extent the intensity and likelihood of an observed extreme weather event have changed due to climate change. This approach has been applied to different types of weather extremes such as heatwaves, droughts, or extreme rainfall, but has only rarely been used to assess the role of climate change on health impacts caused by extreme weather events.

In this study, we focus on the short-term effects of extreme heat events on human mortality in Europe. We first apply an epidemiological model to estimate the lagged association between temperatures and mortality counts. We use ERA5-Land temperature data and a mortality database including 92.612.620 counts of death from 823 contiguous regions in 35 European countries, representing a population of over 534 million people. We estimate the number of deaths attributable to heat and then compute the death count caused by climate change by applying EEA methods. Here, we apply a conditional extreme value distribution to estimate how the likelihood of selected heat-attributable mortality events has changed from a pre-industrial climate to present-day conditions (1.2ºC global warming).

We show that in all regions of Europe, a climate change signal in heat-attributable mortality can be detected. This climate change contribution to mortality differs between geographical locations in Europe and is also influenced by demographic, and socioeconomic factors, e.g., we identify differences in climate impacts in gender-specific mortality.

This study shows that epidemiological models can be combined with EEA methodologies and it opens the door to conducting further EEA studies, including rapid attribution, on other health impacts and beyond.