Mortality Risk Attributable to Thermal Discomfort Indicators with Implications of Climate Change

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Publications

Optimal heat stress metric for modelling heat‐related mortality varies from country to country

Publication . Lo, Eunice; Mitchell, Dann M.; Buzan, Jonathan R.; Zscheischler, Jakob; Schneider, Rochelle; Mistry, Malcolm N.; Kyselý, Jan; Lavigne, Éric; Silva, Susana; Royé, Dominic; Urban, Aleš; Armstrong, Ben; Gasparrini, Antonio; Vicedo‐Cabrera, Ana M.

Combined heat and humidity is frequently described as the main driver of human heat-related mortality, more so than dry-bulb temperature alone. While based on physiological thinking, this assumption has not been robustly supported by epidemiological evidence. By performing the first systematic comparison of eight heat stress metrics (i.e., temperature combined with humidity and other climate variables) with warm-season mortality, in 604 locations over 39 countries, we find that the optimal metric for modelling mortality varies from country to country. Temperature metrics with no or little humidity modification associates best with mortality in ~40% of the studied countries. Apparent temperature (combined temperature, humidity and wind speed) dominates in another 40% of countries. There is no obvious climate grouping in these results. We recommend, where possible, that researchers use the optimal metric for each country. However, dry-bulb temperature performs similarly to humidity-based heat stress metrics in estimating heat-related mortality in present-day climate.

2023-07-12Journal article

Open access

Impact of population aging on future temperature-related mortality at different global warming levels

Publication . Chen, Kai; de Schrijver, Evan; Sivaraj, Sidharth; Sera, Francesco; Scovronick, Noah; Jiang, Leiwen; Roye, Dominic; Lavigne, Eric; Kyselý, Jan; Urban, Aleš; Schneider, Alexandra; Huber, Veronika; Madureira, Joana; Mistry, Malcolm N; Cvijanovic, Ivana; MCC Collaborative Research Network; Gasparrini, Antonio; Vicedo-Cabrera, Ana M

Older adults are generally amongst the most vulnerable to heat and cold. While temperature-related health impacts are projected to increase with global warming, the influence of population aging on these trends remains unclear. Here we show that at 1.5 °C, 2 °C, and 3 °C of global warming, heat-related mortality in 800 locations across 50 countries/areas will increase by 0.5%, 1.0%, and 2.5%, respectively; among which 1 in 5 to 1 in 4 heat-related deaths can be attributed to population aging. Despite a projected decrease in cold-related mortality due to progressive warming alone, population aging will mostly counteract this trend, leading to a net increase in cold-related mortality by 0.1%-0.4% at 1.5-3 °C global warming. Our findings indicate that population aging constitutes a crucial driver for future heat- and cold-related deaths, with increasing mortality burden for both heat and cold due to the aging population.

2024-02-27Journal article

Open access

Regional variation in the role of humidity on city-level heat-related mortality

Publication . Guo, Qiang; Mistry, Malcolm N.; Zhou, Xudong; Zhao, Gang; Kino, Kanon; Wen, Bo; Yoshimura, Kei; Satoh, Yusuke; Cvijanovic, Ivana; Kim, Yoonhee; Ng, Chris Fook Sheng; Vicedo-Cabrera, Ana M.; Armstrong, Ben; Urban, Aleš; Katsouyanni, Klea; Masselot, Pierre; Tong, Shilu; Sera, Francesco; Huber, Veronika; Bell, Michelle L.; Kyselý, Jan; Gasparrini, Antonio; Hashizume, Masahiro; Oki, Taikan; Abrutzky, Rosana; Guo, Yuming; de Sousa Zanotti Stagliorio Coelho, Micheline; Nascimento Saldiva, Paulo Hilario; Lavigne, Eric; Ortega, Nicolás Valdés; Correa, Patricia Matus; Kan, Haidong; Osorio, Samuel; Roye, Dominic; Indermitte, Ene; Orru, Hans; Jaakkola, Jouni J K.; Ryti, Niilo; Pascal, Mathilde; Schneider, Alexandra; Analitis, Antonis; Entezari, Alireza; Mayvaneh, Fatemeh; Zeka, Ariana; Goodman, Patrick; de'Donato, Francesca; Michelozzi, Paola; Alahmad, Barrak; De la Cruz Valencia, César; Hurtado Diaz, Magali; Overcenco, Ala; Ameling, Caroline; Houthuijs, Danny; Rao, Shilpa; Carrasco, Gabriel; Seposo, Xerxes; Madureira, Joana; Silva, Susana; Holobaca, Iulian-Horia; Acquaotta, Fiorella; Scovronick, Noah; Kim, Ho; Lee, Whanhee; Tobias, Aurelio; Íñiguez, Carmen; Forsberg, Bertil; Ragettli, Martina S.; Pan, Shih-Chun; Guo, Yue Leon; Li, Shanshan; Schneider, Rochelle; Colistro, Valentina; Zanobetti, Antonella; Schwartz, Joel; Van Dung, Do; Ngoc Dang, Tran; Honda, Yasushi

The rising humid heat is regarded as a severe threat to human survivability, but the proper integration of humid heat into heat-health alerts is still being explored. Using state-of-the-art epidemiological and climatological datasets, we examined the association between multiple heat stress indicators (HSIs) and daily human mortality in 739 cities worldwide. Notable differences were observed in the long-term trends and timing of heat events detected by HSIs. Air temperature (Tair) predicts heat-related mortality well in cities with a robust negative Tair-relative humidity correlation (CT-RH). However, in cities with near-zero or weak positive CT-RH, HSIs considering humidity provide enhanced predictive power compared to Tair. Furthermore, the magnitude and timing of heat-related mortality measured by HSIs could differ largely from those associated with Tair in many cities. Our findings provide important insights into specific regions where humans are vulnerable to humid heat and can facilitate the further enhancement of heat-health alert systems.

2024-07Journal article

Open access