Toronto surpassed a new all-time temperature high for May 31 on Tuesday as nearly half of southern Ontario was under a special weather statement for the second consecutive day due to heat – occurrences that an expert says will happen more often and earlier in the year as a result of climate change.
The city broke a 78-year-old record with 32.2 C observed at Toronto's Pearson International Airport Tuesday afternoon., Environment Canada said.
The previous highest temperature recorded in Toronto on this date was 31.1 C in 1944.
Blair Feltmate, head of the Intact Centre on Climate Adaptation at the University of Waterloo, said the new record is "climate change in action."
"This is exactly the type of event that was predicted," he said in an interview Tuesday.
"The most recently released report of the Intergovernmental Panel on Climate Change said we can expect heat records to be exceeded on a regular basis, as driven by climate change. And now we're seeing it."
Hot and humid weather prompted Environment Canada to issue a heat warning for Toronto, along with some other areas including the Peel, Windsor-Essex, York and Durham regions. It also issued a special weather statement for a swath of southern Ontario stretching from Barrie to Sarnia.
The agency said minimum temperatures in the low 20s would provide "little relief" from the heat Tuesday night, but that cooler air is expected on Wednesday.
In a recent report titled Irreversible Extreme Heat: Protecting Canadians and Communities From a Lethal Future, the University of Waterloo's Intact Centre projects that extreme temperatures and heat waves in Canada will become more extreme in the future.
The researchers note that Canada is warming, on average, at twice the global rate; annual mean temperatures increased by 1.7 C between 1948 and 2016.
Felmate, an author of the report, said much of Canada is projected to experience extreme temperatures between 2051 and 2080 based on three indicators — maximum daily temperature, number of days where temperatures exceed 30 C and the duration of heat waves.
"The maximum daily temperature is going to go up, the number of days that we experience during the summer, where the temperature exceeds 30 C, are going up, and the length of heat waves will elongate," Feltmate explained.
"So all three dimensions of temperature expression you can look at, they're all going in the wrong direction, driven by climate change."
The report notes that exposure to extreme heat will be most pronounced in three areas of Canada — low-lying areas from the west coast to the Rocky Mountains (British Columbia), the Prairies bordering the United States (southern Alberta, Saskatchewan, and Manitoba) and north of Lake Erie through the St. Lawrence River Valley (southern Ontario and Quebec).
In Toronto, the researchers project there will be 55 very hot days per year — where temperatures exceed 30 C — by 2051, up from the 12 to 14 days the city typically experiences now. That's based on a "high-carbon scenario" that assumes that global greenhouse gas emissions will continue to increase at current rates through the end of the 21st century.
Ottawa is projected to see 57 very hot days every year by 2051, compared to the average 13 to 14 days the city currently experiences.
And in London, Ont., the city is expected to see 61 days each year above 30 C by 2051, up from about 12 days now.
"The onslaught with the expression of extreme heat is such that extreme heat events occur earlier in the season," Feltmate said.
"They last longer at the back end of the season into the late summer and early fall. And the extreme temperatures between the spring and the fall are more extreme within particular urban or suburban areas."
Extreme heat poses a risk for everyone, but especially the elderly, homeless and people with pre-existing health conditions, Feltmate said.
"If they succumb to extreme heat, it's not just inconvenient, they can die," he said, noting that
Nearly 600 people died in British Columbia due to extreme heat last summer, with 526 fatalities recorded in just one week between June 25 and July 1, 2021.
In Quebec, 86 people died due to a heat wave in 2018 during the hottest summer on record there in 146 years of meteorological observations.
Feltmate said urgent action is required to manage risk and avoid worsening impacts – and ultimately fatalities – resulting from rising heat.
He suggested various actions people can take to prepare for extreme heat such as installing heat-reducing windows and shading devices, planting more trees, ensuring buildings have backup electricity supply and making an emergency plan with neighbours.
"The danger is right now. I do not believe that people understand the threat that extreme heat poses. We do not have an appropriate sense of urgency to prepare for extreme heat events. And without that sense of urgency when extreme heat events happen, it will prove to be lethal."
This report by The Canadian Press was first published May 31, 2022.
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This story was produced with the financial assistance of the Meta and Canadian Press News Fellowship.
Noushin Ziafati, The Canadian Press
