The effect of climate warming on the seasonal variation of mortality in European countries

Although several studies have concluded that excess winter deaths are not a suitable indicator of cold-related health impacts, the investigation of temporal fluctuation in mortality across many European countries could provide an insight into the seasonal variation of deaths at different climatic conditions. We investigated the evolution over time of the Excess Winter Deaths Index (EWDI) and the Summer-to-Winter Deaths ratio (S/W) for the period 1960–2018 and the temporal fluctuation of the Heating and Cooling Degree Days indices for the period 1979–2020. We found a clear spatial pattern of EWDI with statistically significant decreasing trends in Mediterranean countries and increasing trends in Nordic countries. On the other hand, S/W index shown increasing trends in Mediterranean region and decreasing trends in Nordic countries. Statistical analysis of Heating Degree Days index showed significant decreasing trends for all European countries, probably due to the appearance of milder winters. Also, the values of Cooling Degree Days index exhibited a statistically significant upward trend for Mediterranean countries, mainly due to increased frequency of warmer summers, as a result of climate change. This study shows that the differences in seasonal variation of mortality between European countries are likely to disappear, as the climate gets warmer. A possible explanation for our findings is that climate change already brings milder winters and hotter summers to the Mediterranean countries, while in the Nordic countries global warming causes less severe winters and more pleasant summers as shown from Heating and Cooling Degree Days analysis. In addition to providing a basis to investigate potential effects of global warming on human mortality, the findings of this study are likely to be crucial for climate change policy and developing relevant adaptation strategies in Europe.

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Opracowanie rekordu ze środków MEiN, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2022-2023).