Climate change sets and breaks heat records across Canada this summer

October 25, 2024 – Ottawa, Ontario

Over the summer, Environment and Climate Change Canada scientists analyzed the devastating heat waves that impacted Canadians. They found that human-caused climate change made almost all of Canada's worst heat waves hotter and more likely.

Environment and Climate Change Canada’s Rapid Extreme Weather Event Attribution system uses climate models to compare today’s climate with a pre-industrial one. This helps Canadians understand how human emissions and activities are affecting our lives and weather today, as the changes unfold.

From June to September 2024, Environment and Climate Change Canada climate scientists analyzed 37 of the hottest heat waves in 17 regions across Canada. They determined that of these heat waves, human-caused climate change made:

• Five of them more likely to occur (at least one to two times more likely)
• Twenty-eight of them much more likely to occur (at least two to 10 times more likely)
• Four of them far more likely to occur (at least 10 times more likely)

Learn more: Understanding the results

As the global climate continues to warm because of increasing greenhouse gas concentrations in the atmosphere, Canada is warming at roughly double the global average rate. Spring and summer are becoming hotter, and this means earlier snowmelt, dangerous heat waves, and conditions that are ripe for wildfires.

Starting this winter, Environment and Climate Change Canada will be able to use its Rapid Extreme Weather Event Attribution system to analyze the connection between human-caused climate change and the odds of extreme cold temperature events. Work is also underway to develop the system to analyze extreme precipitation. This capability is expected to come online in 2025.

The direct and indirect costs of extreme weather are substantial. They can range from loss of productivity to loss of life. Better understanding the causes and effects of extreme weather—such as heat waves, extreme cold, and extreme precipitation—can help us better plan for, respond to, and rebuild from weather emergencies. Recent Canadian studies show that:

• These “once in 100 years” climate-related weather events are becoming more frequent, severe, and costly. 2020, 2021, 2022, and 2023 all rank in the top 10 years based on insurance claims, surpassed only by the 2016 Fort McMurray fires, the 2013 flooding in Calgary and Toronto, and the 1998 Quebec ice storm (source).
• From 1983 to 2008, insurers spent on average $400 million per year on catastrophic claims in Canada. Since 2009, the yearly average has risen to almost $2 billion (source).
• 2023 was the second warmest year on record in Canada since 1948 (when nationwide estimates began) (source).
• From 1948 to 2023, the annual average temperature in Canada increased by 2.0 °C (source).

The public is encouraged to regularly monitor weather forecasts, take all weather alerts seriously, and get prepared for weather-related events by developing an emergency plan and being ready to adjust their travel plans. Canadians can download the WeatherCAN app to receive weather alert notifications directly on their mobile devices. Alerts help Canadians prepare to face severe weather events, save lives, and reduce the impacts on property and livelihoods.