Human-induced climate change has significantly increased the likelihood of heat waves across Canada, according to a report from Environment and Climate Change Canada. The agency announced that summer 2025 was the 11th warmest on record, with temperatures exceeding the average since 1948.

Nathan Gillett, a research scientist with the agency, stated, "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." The analysis focused on data from 17 regions during the summer months, identifying 10 heat waves that surpassed the typical hottest day of the year.

The report highlighted that nine of these heat waves occurred in the Yukon, Northwest Territories, British Columbia, Alberta, and Quebec. These events were found to be two to ten times more likely due to climate change compared to the late 19th century. Specifically, a heat wave in Atlantic Canada on August 13 was determined to be at least ten times more likely as a result of human-caused climate change.

In July, Atlantic Canada experienced another heat wave, with peak daily temperatures reaching 25.6 degrees Celsius. The analysis also noted that northern Quebec faced two heat waves in July and August, with temperatures exceeding normal highs by 7 degrees Celsius. Fort Smith in the Northwest Territories recorded an eight-day heat wave with temperatures soaring 10 degrees Celsius above normal.

The longest heat event analyzed occurred in northern British Columbia, lasting from August 23 to September 9. The hottest day was recorded on August 11 in southern Quebec, with temperatures reaching 29.3 degrees Celsius.

The rapid extreme weather event attribution system used in the study simulates weather patterns from the late 1800s, before the significant impacts of human-induced climate change. By comparing these historical models with current data, scientists can assess how greenhouse gas emissions have increased the likelihood of extreme weather events.

Gillett emphasized the importance of understanding human influence on extreme weather, stating that it can aid policymakers in planning for and responding to emergencies. A report from the Intact Centre on Climate Adaptation indicated that insurance losses in Canada have surged from an average of $456 million per year between 1983 and 2008 to over $2 billion annually since 2008, primarily due to water-related damage from extreme flooding.

The report identified flooding, wildfires, and extreme heat as significant risks associated with climate change. Gillett mentioned that the extreme weather event system is being expanded to analyze extreme precipitation and cold events. He noted that while extreme cold events are becoming less frequent, higher-than-normal precipitation is occurring more often and with greater intensity.

Anabela Bonada, managing director of climate science at the Intact Centre for Climate Adaptation, stated, "When we can attribute an event to climate change, then it makes it real for us. We can communicate it to the public more clearly so they understand what they need to prepare for." Bonada highlighted the need for regions across Canada to prepare for extreme heat, noting that climate change is affecting areas that previously experienced different weather patterns.

She pointed out that drought conditions in Atlantic Canada are impacting the agricultural industry, while high temperatures have increased wildfire risks in southern Ontario. Bonada warned that areas not typically prone to wildfires or drought should start to expect these events as climate change continues to evolve.