The silent threat of heat waves

Extreme heat events can be deadly, and they’re happening more often — so why aren’t we taking them seriously?
By Tim Alamenciak - Published on Jun 15, 2017
Cities tend to be hotter than rural areas because they absorb heat and continue to release it after dark — a phenomenon known as the urban heat island effect. (NISARG MEDIA/CP)



Coping with the cold is the norm in Ontario. Many of us live in well-insulated buildings, enjoy toasty heating systems, and have Rubbermaid bins full of winter gear. It seems as if every kid in this province is born knowing how to get warm.

On the other hand, not every Ontarian knows how to get cool. But with climate change making extreme heat events the norm, we’ll have to learn — and in a province built to withstand winter, that will require big changes in the way we think and behave.

More hot days (defined generally as having temperatures above 30 C) are a symptom of global warming — which is exacerbated by the very methods we turn to for relief. Air conditioning not only increases our energy consumption; it also releases ambient heat. Scientists in 2012 projected the number of hot days would nearly double in Toronto, Winnipeg, and Fredericton by 2070 at the latest.

Cities already tend to be hotter than rural areas because of the urban heat island effect. People, cars, pavement, and large buildings all release heat, which builds up in the air — and continue to release it into the night, so that the city never really has a chance to cool down.

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Yet bracing the province for heat waves has taken a backseat to dealing with flooding and other extreme weather events. Blair Feltmate, head of the Intact Centre on Climate Adaptation at the University of Waterloo, says this is in part because it can be difficult to quantify the financial and human cost of heat waves.

“At least when we’re talking about programs to mitigate the negative impacts of flooding, we can put a number on that and say this is what it’s costing us,” Feltmate says. “Heat’s not in the same category right now. We simply don’t have numbers on it other than to know when we have excessive heat, it may cause vulnerable populations to suffer.”

We do know that heat waves can be deadly. In 2010, a five-day heat wave killed about 280 people in Quebec. Fifteen years earlier, a Chicago heat wave killed 739. And in 2003, scorching temperatures caused an estimated 70,000 deaths in 16 countries across Europe.

Floods destroy buildings, shut down streets, and damage landscapes. Heat waves, by comparison, are more insidious, killing seniors who have nobody to check on them. Heat waves do their damage behind closed doors, in the sweltering apartments of those without the means or ability to stay cool.

“We are definitely concerned with this because we’re dealing with seniors, children, people with chronic illnesses, people with disabilities,” says Mary Todorow, research and policy analyst with the Advocacy Centre for Tenants in Ontario. “We think they’re going to be disproportionately impacted by these rising temperatures and not able to pay their electricity bills.”


One possible solution would be for the province to mandate that landlords ensure their units adhere to a maximum temperature. Ontario rentals must maintain a minimum internal temperature of 21 C, but no such provision exists to keep units reasonably cool. The Toronto Board of Health discussed heat vulnerability as recently as May, but didn’t implement  a maximum temperature rule.

“They wanted to adopt a health-based maximum temperature, but there were complications in terms of poorly insulated buildings, the lack of ductwork, and the cost being passed on to tenants,” Todorow says.

Feltmate says it’s important to look at all the potential ramifications of heat waves — from their impacts on everything from transportation systems to the electrical grid — which can affect renters and owners of all kinds but present a particular challenge to people living in high-rises who rely on elevators.

“If you have a critical outage and a single mother with three small kids sitting on the 22nd floor of a building, they can’t just run up and down the stairs,” Feltmate says. ”They’re stranded.”

There are preparations taking place across the province. Peter Berry, senior policy analyst in Health Canada’s climate change and health policy division, edited a book with the Institute for Catastrophic Loss Reduction consisting of 20 case studies highlighting cities across Canada that are taking steps to deal with heat waves.

“Unless we change how we design our communities and how we respond to extreme heat events, more people will be at risk of dying as a result of extreme heat,” writes Paul Kovacs, founder of the ICLR, in the introduction.

The book explores measures from elaborate warning systems targeting vulnerable populations to detailed street tree planning intended to provide greater access to shade. Adapting to a warming climate is more complicated than simply ensuring people stay cool, Feltmate says, though that is an essential component.

“It’s a categorical guarantee that excessive heat beyond what we’ve experienced today is going to be the reality of the future,” he adds. “Therefore we need to prepare now.”

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