From tree cover to green roofs, how are cities fighting extreme heat?

Studies have shown cities can see higher temperatures during heat waves compared with rural areas, but cities are taking steps to try to reduce that impact.

As a heat wave grips parts of Ontario amid a scorching summer, some Canadian cities have been trying new techniques to try to tackle extreme heat, which can quickly turn deadly.

A Statistics Canada study last year showed there were roughly 670 deaths between 2000 and 2020 attributable to extreme heat events in 12 Canadian cities.

In 2021, a heat dome in British Columbia killed an estimated 619 people in one week.

And this week, temperatures in parts of Ontario are set to feel like the mid-40s C — and cities can feel the heat keenly due to how they’re built, experts say.

“The surfaces in the cities are such that they absorb more heat and that causes the entire environment to become hotter and the temperature rises as well,” said Sandeep Agrawal, a professor at the University of Alberta’s School of Urban and Regional Planning.

It’s due to the “urban heat island effect,” which can make a city one to three degrees hotter than the surrounding area during the day and warmer at night, according to decades of urban studies.

Among the reasons are glassy or concrete skyscrapers that absorb a lot of heat during the day and take longer to cool down at night.

James Voogt, a Western University professor of geography and environment, said heat is a top “weather hazard.”