Canada heat waves in 2025 tied to human-driven climate change
There were were several exceptional heat waves this year that Environment and Climate Change Canada (ECCC) linked to human-caused climate change. How does it determine that? It makes the connection with its new, unique attribution system
With a long list of heat waves in Canada in 2025, it should come as no surprise that some of events this year have been linked to human-caused climate change--similar to affairs that occurred in 2024.
That's according to Environment and Climate Change Canada (ECCC), reviewed the extreme heat waves that affected millions of Canadians this year. As they did last year, scientists reviewed data from a number of events and came to a conclusion using its newly developed attribution system.
RELATED: Climate change exacerbated Canada's summer heat waves: ECCC
To help examine Canada's extreme events in 2024 and 2025--and future occurrences--ECCC established a rapid extreme weather event attribution system to compare today's climate with the pre-industrial state. It uses a tool to reveal how human-caused climate change has affected the chances of an extreme weather event, based on recorded levels of greenhouse gases and other human-created activities.
For the events this year, they examined 10 of the hottest heat waves that affected Canada in July and August. Its rapid extreme weather attribution system constantly looks for extreme heat and cold events across Canada.
The system indicates that of the 10 heat waves, nine were made "much more likely" because of climate change, according to ECCC.
"The system shows that the heat waves experienced in these regions during July and August would have been rare in a pre-industrial climate," ECCC said in a news release.
Events linked to climate change
As a result of ECCC's investigation, human influence on the climate made the following heat waves at least two to 10 times more likely to occur:
Alberta (Aug. 25-31)
*denotes the average over the region
Peak, daily-high temperature during the heat wave: 28.8 C*
Degrees above normal, daily-high temperature: 9.3 C
Fort Smith, N.W.T. (Aug. 24-31)
Peak, daily-high temperature during the heat wave: 25.5 C*
Degrees above normal, daily-high temperature: 11.6 C
(Getty Images-804324404-170667a)
Southern British Columbia (Aug. 23 to Sept. 7)
Peak, daily-high temperature during the heat wave: 27.1 C*
Degrees above normal, daily-high temperature: 10.3 C
Northern British Columbia (Aug. 23 to Sept. 9)
Peak, daily-high temperature during the heat wave: 23.5 C*
Degrees above normal, daily-high temperature: 9.6 C
Southern Quebec (Aug. 7-13)
Peak, daily high temperature during the heat wave: 29.3 C*
Degrees above normal, daily-high temperature: 9.1 C
Northern Quebec (Aug. 6-9)
Peak, daily-high temperature during the heat wave: 23.8 C*
Degrees above normal, daily-high temperature: 7.0 C
(Getty Images: Credit: LFO62 Creative #: 1147294367)
Fort Smith, N.W.T. (July 30 to Aug. 1)
Peak, daily-high temperature during the heat wave: 25.2 C*
Degrees above normal, daily-high temperature: 6.0 C
Atlantic Canada (July 10-15)
Peak, daily-high temperature during the heat wave: 25.6 C*
Degrees above normal, daily-high temperature: 7.1 C
Northern Quebec (July 10-13)
Peak, daily-high temperature during the heat wave: 24.2 C*
Degrees above normal, daily-high temperature: 7.5 C
A jet stream forecast for Eastern Canada during the weekend of Aug. 9-10, 2025. (The Weather Network)
As well, in August, a heat wave in Atlantic Canada was "far more likely" to happen due to climate change, with ECCC saying that particular event was "at least 10 times" more likely to occur as a result.
Atlantic Canada (Aug. 7-14)
Peak, daily-high temperature during the heat wave: 28.4 C*
Degrees above normal, daily-high temperature: 9.6 C
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This past winter, ECCC started reviewing the link between human-caused climate change and extreme cold temperatures. Scientists will then examine extreme precipitation events at a later date in 2025. Just like with extreme hot events, human influence on the climate increases the chances of intense precipitation events, ECCC said.
