This article was written by Mariya Postelnyak and Fatima Raza, and was published in the Globe & Mail on June 18, 2024.
Millions of Canadians in Central Canada and the Maritimes were under heat warnings as they prepared for dangerous temperatures that could feel as high as 45 degrees in some areas this week, prompting local officials to urge residents to take precautions to protect themselves.
Environment Canada issued warnings for much of Southern Ontario and Southern Quebec, most of New Brunswick and parts of Nova Scotia. The weather office said daytime temperatures were expected to reach 30 to 35 across most of the affected regions, which would feel more like 45 when the humidity is taken into account. The nighttime will bring little relief with lows lingering above 20.
“It’s certainly out of the norm,” meteorologist Gerald Cheng said.
Armel Castellan, a warning preparedness meteorologist for Environment Canada, said hot weather is especially dangerous.
“Our most deadly weather variable is heat,” he said.
“Heat stroke is an emergency and people die from it in their own homes. … What we’re mostly concerned about is indoor temperatures. That’s where most people spend their time and inside temperatures creep up.”
The City of Toronto responded to the heat wave by announcing extended hours for 10 of its outdoor pools, some of which will be open as late as 11:45 p.m. starting Tuesday.
The city had already implemented its summer heat strategy, which includes street outreach for vulnerable populations and Toronto’s Heat Relief Network, which includes libraries, community centres, and non-profits such as the YMCA. The city added 200 “cool spaces” on top of 400 that were already in place.
Some Ontario communities such as Niagara Falls and Collingwood also opened cooling stations in public buildings.
In Ottawa, the city urged residents to visit public facilities to seek relief from the heat, though it did not plan to open cooling centres.
Last year was the hottest year in recorded history globally, as climate change makes such severe weather more common. There have been deadly heat waves in Canada in recent years, notably British Columbia’s 2021 extreme heat event that saw more than 600 deaths. A heat wave in 2018 was linked to 86 deaths in Quebec, including 66 in Montreal.
Beyond the heat itself, it’s the quick change in temperature that hits the body hard, said Myles Sergeant, an assistant clinical professor in McMaster University’s Department of Family Medicine.
“It takes the body about a week to acclimatize – but now we have these massive shifts in temperature,” he said.
Those most vulnerable to extreme heat include elderly people and children, whose bodies aren’t able to regulate heat as well. But diabetics, pregnant women and those taking medications such as diuretics, laxatives and anti-psychotics are also at risk, Dr. Sergeant said.
Those living alone are also highly vulnerable to extreme heat, according to Karen Smith, an assistant professor in the Department of Physical and Environmental Sciences at the University of Toronto. “They don’t have someone to say, ‘Hey, you don’t look so great. Maybe you need someone to take you somewhere or go to a cooling centre.’ ”
Though Dr. Smith said weather patterns like these are not totally out of the ordinary, their magnitude is growing because of climate change. “In the 1970s and 80s, there would be about 12 days a year with conditions like this,” she said. “But going forward, it will be 30 days a year with days like this.”
Jeffrey Brook, scientific director at the Canadian Urban Environmental Health Research Consortium, said adaptability to extreme heat needs to accelerate in Canada, pointing to the deadly 2021 heat wave in B.C.
“One thing we learned about the heat dome in British Columbia was that, hey, these things can happen and we’re not prepared to deal with it,” he said, pointing out that air conditioning was not as common in many of the affected areas.
Dr. Brook and his team built healthyplan.city, a publicly available tool that allows users to overlay a map of heat pockets in a city with areas where vulnerable populations live. “A planner for a hospital could see, ‘My hospital serves this area and I see that area has more vulnerable people and more potential for greater heat, so I want to make sure we have more people able to respond.’ ”
Anti-poverty activists have previously pointed to severe weather to call for more year round indoor spaces where vulnerable people can escape the elements, rather than only during emergencies.
“This is a time when the city really has to step up to save lives,” said Rafi Aaron, spokesperson for the Interfaith Coalition to Fight Homelessness.
Mr. Aaron said the problem seems to be Toronto’s “seasonal approach.”
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