Kim Perrotta, May 30, 2026
Published in The Hamilton Spectator, May 30, 2026
On May 18th, the first heat warning of the year was issued for much of southern Ontario. With human-induced climate change, heat waves are increasing in frequency, intensity and duration across the country. Last year, for example, heat warnings were issued for 29 days in the Toronto region. We are living in communities that were not designed and built for the climate we are now experiencing.
Extreme heat can be incredibly dangerous. It can cause dehydration, heat exhaustion, and heatstroke, a condition which can be life-threatening for the healthiest of people. It has been linked to adverse reproductive outcomes such as miscarriages, aggressive behaviour, and an increase in violent crimes. Extreme heat can also aggravate chronic health conditions such as heart and lung diseases, diabetes, and mental health disorders; sometimes with deadly outcomes.
Heat waves can be particularly dangerous for very young children and older people as well as pregnant women and people with chronic diseases. But they can also be dangerous for people who have little opportunity or few resources to control their exposure. This can include people who work outdoors, those who live or work in buildings that lack air conditioning, and people who have no homes at all.
The 2021 heat dome that hit British Columbia (BC) provided a heart-breaking example of the human costs of extreme heat. BC’s Coroner concluded that extreme heat that week resulted in the early deaths of 619 across the province and that 98% of those deaths occurred indoors. During that week, death rates for people living in the community of the Greater Vancouver area increased by 440%. Death rates were much higher among older people and among those who live on low incomes. They were also higher in homes that lacked air conditioners and in neighbourhoods with fewer trees and vegetation.
Many municipalities across Canada have developed action plans to protect their residents from extreme heat. Some, such as Toronto and Hamilton, are now providing air conditioners to those residents who are at greatest risk of harm from extreme heat. A number of municipalities are also working to increase their community’s heat resilience by investing in trees and green infrastructure and promoting green buildings that are cooler and energy efficient.
But to save lives, prevent harm, and manage healthcare costs, we need action from our provincial government as well. The Ontario Government must recognize how the changing climate is impacting human health. It must ensure that workplaces regulations and policies are adequately protecting indoor and outdoor workers from increasing temperatures. It must ensure that people who live in apartments are protected from extreme heat as well as from cold. It must provide our schools, municipalities and public health units with the resources they need to prepare for, and respond to, extreme heat events. And it must invest in low-income housing to ensure that all our citizens have a safe place to live. It is time for the Ontario Government to get serious about climate resiliency; to protect its citizens from extreme heat.