Analysis of community deaths during the catastrophic 2021 heat dome

Abstract

Background: British Columbia, Canada, was impacted by a record-setting heat dome in early summer 2021. Most households in greater Vancouver do not have air conditioning, and there was a 440% increase in community deaths during the event. Readily available data were analyzed to inform modifications to the public health response during subsequent events in summer 2021 and to guide further research. Methods: The 434 community deaths from 27 June through 02 July 2021 (heat dome deaths) were compared with all 1,367 community deaths that occurred in the same region from 19 June through 09 July of 2013–2020 (typical weather deaths). Conditional logistic regression was used to examine the effects of age, sex, neighborhood deprivation, and the surrounding environment. Data available from homes with and without air conditioning were also used to illustrate the indoor temperatures differences. Results: A combined index of material and social deprivation was most predictive of heat dome risk, with an adjusted odds ratio of 2.88 [1.85, 4.49] for the most deprived category. Heat dome deaths also had lower greenness within 100 m than typical weather deaths. Indoor temperatures in one illustrative home without air conditioning ranged between 30°C and 40°C. Conclusions: Risk of death during the heat dome was associated with deprivation, lower neighborhood greenness, older age, and sex. High indoor temperatures likely played an important role. Public health response should focus on highly deprived neighborhoods with low air conditioning prevalence during extreme heat events. Promotion of urban greenspace must continue as the climate changes.

Excess mortality, COVID-19 and health care systems in Canada

“…In BC, Alberta and Saskatchewan, periods early in the pandemic and at the end of the reported period saw excess mortality rates far higher than those for COVID-19. In particular, BC saw a notable, sustained divergence after the spike in deaths related to the 2021 “heat dome.” 7 …”

“…Some provinces, especially BC, had an unexpected heat dome in June and July 2021, which, as noted, was associated with a spike in deaths. Human Rights Watch concluded that an inadequate policy response contributed to heat-related deaths in BC, 10 and that these deaths were highly associated with social and material deprivation, 7 which may have been related to the COVID-19 pandemic. Pandemic policies and border shutdowns likely also contributed to an unsafe drug supply, more people using alone and other social factors that contributed to higher rates of opioid-related deaths.…”

The existential risk space of climate change

“…These metrics, hence, define existential risks, because they indicate certain thresholds beyond which risks become existential, according to scientific or societal standards. Recent examples where extraordinary high magnitudes were reached are the devastating 2021 floods in western Europe with statistically extremely high rainfall intensities and flood discharges (Fekete and Sandholz 2021 ), or the heatwave (heatdome) that struck the northwestern USA and southwestern Canada in 2021 with extremely high temperatures close to 50°C (Henderson et al 2022 ). Other types of metrics for magnitude relate to the number of affected people, the geographic or administrative area affected (e.g., from provincial to national scale), the area of arable land, or the number of systems or sectors affected (e.g., food and energy production systems) (IPCC 2014 , 2018 , 2019b ; Hirabayashi et al 2021 ).…”

Surmortalité, COVID-19 et systèmes de santé au Canada

“…En Colombie-Britannique, en Alberta et en Saskatchewan, le début de la pandémie et la fin de la période étudiée ont été associés à des taux de surmortalité beaucoup plus élevés que les taux de mortalité liée à la COVID-19. La Colombie-Britannique, en particulier, a connu un important écart soutenu après le pic de mortalité liée au « dôme de chaleur », en 2021 7 .…”

“…Certaines provinces, surtout la Colombie-Britannique, ont connu un dôme de chaleur inattendu en juin et juillet 2021 qui a été associé à un pic de mortalité. Human Rights Watch a conclu qu’une réponse inadéquate des pouvoirs publics avait contribué aux décès liés à la chaleur en Colombie-Britannique 10 et que ces décès étaient étroitement liés à des difficultés sociales et matérielles 7 ayant peut-être été associées à la pandémie de COVID-19. Les politiques et les fermetures de frontières adoptées en raison de la pandémie ont aussi probablement favorisé la mise en circulation de drogues dangereuses, la consommation en solitaire et d’autres facteurs sociaux ayant contribué à l’augmentation des taux de décès par surdose d’opioïdes 11 .…”