New research by Statistics Canada reveals that Toronto, Surrey, Quebec City, and Montreal are among the most lethal cities in Canada for heatwave-related deaths. This comprehensive study examined daily mortality data from the 12 most populous cities in Canada, spanning from 2000 to 2020, to understand the impact of extreme heat on public health.
Study Findings
Statistics Canada’s analysis utilized generalized additive models to assess daily mortality risks linked to non-accidental, cardiovascular, and respiratory causes of death. The study focused on two age groups: those under 65 years and those 65 years and older. The findings highlighted a significant increase in mortality risks during extreme heat events, particularly affecting older adults.
Key points from the research include:
- Elevated Mortality Risks: Most cities showed increased mortality risks during extreme heat events, particularly for non-accidental and respiratory causes. The impact was more pronounced among people aged 65 and older.
- City-Specific Data: Montreal, Quebec City, Surrey, and Toronto reported significantly higher non-accidental mortality risks during heatwaves for the elderly. Cardiovascular and respiratory mortality risks were also notably higher for older adults in Montreal and Toronto.
- Excess Deaths: Across the 12 cities studied, approximately 670 excess non-accidental deaths, 115 excess cardiovascular deaths, and 115 excess respiratory deaths were attributed to extreme heat events over the 20-year period. Toronto and Montreal experienced the most significant spikes, with an estimated 250 and 295 excess deaths, respectively.
Additional Insights
The study also found that cities with higher proportions of renter households and fewer extreme heat events tend to have higher mortality risks during heatwaves. This correlation may be due to the limited access to air conditioning among renters compared to homeowners.
“One explanation … may be the concentration of rental housing and lower levels of air conditioning access among renters, compared with owners,” the study reads.
Broader Implications
While Toronto and Montreal saw the highest mortality rates due to heatwaves, other cities like Quebec City, Ottawa, Surrey, Vancouver, Brampton, and Mississauga reported between 22 and 34 excess deaths during the study period. Interestingly, Calgary, Winnipeg, Edmonton, and Hamilton showed slightly lower mortality figures during extreme heat events compared to their baselines.
This 20-year review underscores the urgent need for adaptive measures and policies to mitigate the effects of extreme heat, particularly in urban areas with vulnerable populations. Enhanced public health strategies, increased access to cooling facilities, and improved housing conditions are essential steps to protect residents from the deadly impacts of heatwaves.