Climate change made Atlantic Canada heat wave at least 10 times more likely: ECCC

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This article was published 17/09/2025 (361 days ago), so information in it may no longer be current.

Human-caused climate change made a record-breaking heat wave in Atlantic Canada far more likely, federal climate scientists said Wednesday, as they released a new analysis of 10 of Canada’s hottest heat events in July and August. 

The results suggest the weeklong heat wave over Atlantic Canada was made at least 10 times more likely because of climate change. That was more than any of the others, said Environment and Climate Change Canada research scientist Nathan Gillett.

Figuring out how much human influence — largely from the burning of fossil fuels — is increasing the likelihood of dangerous weather extremes can help decisionmakers “better plan for, better respond to and better (rebuild) following weather emergencies,” Gillett said.

“Heat waves are one of the most dangerous, if not the most dangerous weather-related hazard both globally and in Canada,” he said Wednesday. 

“Understanding how the risks are changing can help inform decision-making to protect the health, safety and property of Canadians. And it can also help planning climate change adaptation efforts.”

The Atlantic Canada heat wave from Aug. 7 to 14 saw the region’s average peak daily temperatures soar almost 10 degrees above normal.

Maple Plains, P.E.I., set an all-time provincial temperature record on Aug. 12 when the mercury rocketed up to 38 C. Newfoundland’s Avalon Peninsula saw a record seven days of consecutive heat warnings. 

Scientists with ECCC came up with their results by comparing models of the Earth’s current and pre-industrial climate to see how carbon dioxide and other planet-warming emissions increased the chances of extreme heat. 

They break Canada down into 17 broad regions and will only analyze a heat wave when temperatures exceed the typical hottest day of the year for that region. 

The other nine heat waves analyzed in July and August were all made at least two to 10 times more likely due to climate change, Gillett said.

That included the late-August heat waves over Alberta and Fort Smith, N.W.T., and a three-day long July heat wave over northern Quebec. 

The federal scientists have also started to do similar studies of extreme precipitation, and plan to start releasing those results later this year. 

This report by The Canadian Press was first published Sept. 17, 2025.