Human-made climate change made 10 summer heat waves more likely: experts

Human-caused climate change made several heat waves across Canada two to 10 times more likely, Environment and Climate Change Canada said Wednesday.

The agency said summer 2025 was the 11th warmest on record and, while not “exceptional,” was warmer than the average since 1948.

“The strongest event, the most extreme event of the summer was observed in Atlantic Canada, which we found to be at least 10 times more likely because of human-induced climate change,” said Nathan Gillett, a research scientist with Environment and Climate Change Canada.

Environment and Climate Change Canada analyzed data from 17 regions of the country this summer when temperatures during a heat wave exceeded the typical hottest day of the year. For July and August, 10 met that threshold.

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