Seasonality of mortality under climate change: a multicountry projection study
Abstract
BACKGROUND: Climate change can directly impact temperature-related excess deaths and might subsequently change the seasonal variation in mortality. In this study, we aimed to provide a systematic and comprehensive assessment of potential future changes in the seasonal variation, or seasonality, of mortality across different climate zones. METHODS: In this modelling study, we collected daily time series of mean temperature and mortality (all causes or non-external causes only) via the Multi-Country Multi-City Collaborative (MCC) Research Network. These data were collected during overlapping periods, spanning from Jan 1, 1969 to Dec 31, 2020. We projected daily mortality from Jan 1, 2000 to Dec 31, 2099, under four climate change scenarios corresponding to increasing emissions (Shared Socioeconomic Pathways [SSP] scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). We compared the seasonality in projected mortality between decades by its shape, timings (the day-of-year) of minimum (trough) and maximum (peak) mortality, and sizes (peak-to-trough ratio and attributable fraction). Attributable fraction was used to measure the burden of seasonality of mortality. The results were summarised by climate zones. FINDINGS: The MCC dataset included 126 809 537 deaths from 707 locations within 43 countries or areas. After excluding the only two polar locations (both high-altitude locations in Peru) from climatic zone assessments, we analysed 126 766 164 deaths in 705 locations aggregated in four climate zones (tropical, arid, temperate, and continental). From the 2000s to the 2090s, our projections showed an increase in mortality during the warm seasons and a decrease in mortality during the cold seasons, albeit with mortality remaining high during the cold seasons, under all four SSP scenarios in the arid, temperate, and continental zones. The magnitude of this changing pattern was more pronounced under the high-emission scenarios (SSP3-7.0 and SSP5-8.5), substantially altering the shape of seasonality of mortality and, under the highest emission scenario (SSP5-8.5), shifting the mortality peak from cold seasons to warm seasons in arid, temperate, and continental zones, and increasing the size of seasonality in all zones except the arid zone by the end of the century. In the 2090s compared with the 2000s, the change in peak-to-trough ratio (relative scale) ranged from 0·96 to 1·11, and the change in attributable fraction ranged from 0·002% to 0·06% under the SSP5-8.5 (highest emission) scenario. INTERPRETATION: A warming climate can substantially change the seasonality of mortality in the future. Our projections suggest that health-care systems should consider preparing for a potentially increased demand during warm seasons and sustained high demand during cold seasons, particularly in regions characterised by arid, temperate, and continental climates. FUNDING: The Environment Research and Technology Development Fund of the Environmental Restoration and Conservation Agency, provided by the Ministry of the Environment of Japan.
Related
- Projection of hydrological droughts in the upper Hanjiang River under the climate change impact based on stacking machine learning model
- Forecasting Lives Lost to Climate Change: A Precautionary Empirical Framework for Climate-Related Mortality
- Climate Change Finance and Carbon Offsets: Addressing Global Climate Challenges through Innovative Funding and Emissions Reduction Mechanisms
- Trends in Climate Change Disinformation within Latino Communities
- Integrated methodology to assess windthrow impacts on forest stands under climate change
BibTeX
@article{madaniyazi2026seasonality,
title = {{Seasonality of mortality under climate change: a multicountry projection study}},
author = {Lina Madaniyazi and Ben Armstrong and Aurelio Tobias and Malcolm Mistry and Michelle Bell and Aleš Urban and Jan Kyselý and Niilo Ryti and Ivana Cvijanovic and Chris Fook Sheng Ng and Dominic Roye and Ana Maria Vicedo-Cabrera and Shilu Tong and Eric Lavigne and Carmen Íñiguez and Susana das Neves Pereira da Silva and Joana Madureira and Jouni Jaakkola and Francesco Sera and Yasushi Honda and Antonio Gasparrini and Masahiro Hashizume and Rosana Abrutzky and Fiorella Acquaotta and Barrak Alahmad and Antonis Analitis and Hanne Krage Carlsen and Gabriel Carrasco-Escobar and Micheline de Sousa Zanotti Stagliorio Coelho and Valentina Colistro and Patricia Matus Correa and Tran Ngoc Dang and Francesca De'Donato and Magali Hurtado Diaz and Do Van Dung and Alireza Entezari and Bertil Forsberg and Patrick Goodman and Yue Leon Guo and Yuming Guo and Iulian-Horia Holobaca and Danny Houthuijs and Veronika Huber and Ene Indermitte and Haidong Kan and Klea Katsouyanni and Yoonhee Kim and Ho Kim and Whanhee Lee and Shanshan Li and Fatemeh Mayvaneh and Paola Michelozzi and Hans Orru and Nicolás Valdés Ortega and Samuel Osorio and Ala Overcenco and Shih-Chun Pan and Mathilde Pascal and Martina Ragettli and Shilpa Rao},
journal = {Lancet Planetary Health},
year = {2026},
month = oct,
doi = {10.1016/s2542-5196(23)00269-3},
url = {https://hal.science/hal-05783962v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Seasonality of mortality under climate change: a multicountry projection study
AU - Lina Madaniyazi
AU - Ben Armstrong
AU - Aurelio Tobias
AU - Malcolm Mistry
AU - Michelle Bell
AU - Aleš Urban
AU - Jan Kyselý
AU - Niilo Ryti
AU - Ivana Cvijanovic
AU - Chris Fook Sheng Ng
AU - Dominic Roye
AU - Ana Maria Vicedo-Cabrera
AU - Shilu Tong
AU - Eric Lavigne
AU - Carmen Íñiguez
AU - Susana das Neves Pereira da Silva
AU - Joana Madureira
AU - Jouni Jaakkola
AU - Francesco Sera
AU - Yasushi Honda
AU - Antonio Gasparrini
AU - Masahiro Hashizume
AU - Rosana Abrutzky
AU - Fiorella Acquaotta
AU - Barrak Alahmad
AU - Antonis Analitis
AU - Hanne Krage Carlsen
AU - Gabriel Carrasco-Escobar
AU - Micheline de Sousa Zanotti Stagliorio Coelho
AU - Valentina Colistro
AU - Patricia Matus Correa
AU - Tran Ngoc Dang
AU - Francesca De'Donato
AU - Magali Hurtado Diaz
AU - Do Van Dung
AU - Alireza Entezari
AU - Bertil Forsberg
AU - Patrick Goodman
AU - Yue Leon Guo
AU - Yuming Guo
AU - Iulian-Horia Holobaca
AU - Danny Houthuijs
AU - Veronika Huber
AU - Ene Indermitte
AU - Haidong Kan
AU - Klea Katsouyanni
AU - Yoonhee Kim
AU - Ho Kim
AU - Whanhee Lee
AU - Shanshan Li
AU - Fatemeh Mayvaneh
AU - Paola Michelozzi
AU - Hans Orru
AU - Nicolás Valdés Ortega
AU - Samuel Osorio
AU - Ala Overcenco
AU - Shih-Chun Pan
AU - Mathilde Pascal
AU - Martina Ragettli
AU - Shilpa Rao
PY - 2026
DA - 2026/10/07
JO - Lancet Planetary Health
DO - 10.1016/s2542-5196(23)00269-3
UR - https://hal.science/hal-05783962v1
AB - BACKGROUND: Climate change can directly impact temperature-related excess deaths and might subsequently change the seasonal variation in mortality. In this study, we aimed to provide a systematic and comprehensive assessment of potential future changes in the seasonal variation, or seasonality, of mortality across different climate zones. METHODS: In this modelling study, we collected daily time series of mean temperature and mortality (all causes or non-external causes only) via the Multi-Country Multi-City Collaborative (MCC) Research Network. These data were collected during overlapping periods, spanning from Jan 1, 1969 to Dec 31, 2020. We projected daily mortality from Jan 1, 2000 to Dec 31, 2099, under four climate change scenarios corresponding to increasing emissions (Shared Socioeconomic Pathways [SSP] scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). We compared the seasonality in projected mortality between decades by its shape, timings (the day-of-year) of minimum (trough) and maximum (peak) mortality, and sizes (peak-to-trough ratio and attributable fraction). Attributable fraction was used to measure the burden of seasonality of mortality. The results were summarised by climate zones. FINDINGS: The MCC dataset included 126 809 537 deaths from 707 locations within 43 countries or areas. After excluding the only two polar locations (both high-altitude locations in Peru) from climatic zone assessments, we analysed 126 766 164 deaths in 705 locations aggregated in four climate zones (tropical, arid, temperate, and continental). From the 2000s to the 2090s, our projections showed an increase in mortality during the warm seasons and a decrease in mortality during the cold seasons, albeit with mortality remaining high during the cold seasons, under all four SSP scenarios in the arid, temperate, and continental zones. The magnitude of this changing pattern was more pronounced under the high-emission scenarios (SSP3-7.0 and SSP5-8.5), substantially altering the shape of seasonality of mortality and, under the highest emission scenario (SSP5-8.5), shifting the mortality peak from cold seasons to warm seasons in arid, temperate, and continental zones, and increasing the size of seasonality in all zones except the arid zone by the end of the century. In the 2090s compared with the 2000s, the change in peak-to-trough ratio (relative scale) ranged from 0·96 to 1·11, and the change in attributable fraction ranged from 0·002% to 0·06% under the SSP5-8.5 (highest emission) scenario. INTERPRETATION: A warming climate can substantially change the seasonality of mortality in the future. Our projections suggest that health-care systems should consider preparing for a potentially increased demand during warm seasons and sustained high demand during cold seasons, particularly in regions characterised by arid, temperate, and continental climates. FUNDING: The Environment Research and Technology Development Fund of the Environmental Restoration and Conservation Agency, provided by the Ministry of the Environment of Japan.
SN - 2542-5196
SN - 2542-5196
ER -