Climate change fuels August heat waves across Canada

Results from Canada's Rapid Extreme Weather Event Attribution system demonstrate that human-caused climate change made heat waves at least 10 times more likely in August in some instances

OTTAWA, ON, Sept. 25, 2024 /CNW/ - Analysis from Environment and Climate Change Canada's Rapid Extreme Weather Event Attribution has shown that, in all cases, human-caused climate change made heat waves in August 2024 more likely to have occurred. In some instances, it was at least 10 times more likely.

This system uses climate models to compare today's climate with a pre-industrial one to explain how much human-caused climate change affected the likelihood of each heat wave.

In three cases, human-caused climate change made heat waves far more likely to occur. This means that human influence on the climate made the following events at least 10 times more likely to happen:

Inuvik, Northwest Territories (August 6 to 10)

• Peak daily high temperature during the heat wave: 26.5 °C
• Degrees above normal daily high temperature*: 13.0 °C

Kitikmeot, Nunavut (August 7 to12)

• Peak daily high temperature during the heat wave: 25.0 °C
• Degrees above normal daily high temperature*: 12.4 °C

Kivalliq, Nunavut (August 8 to 14)

• Peak daily high temperature during the heat wave: 27.1 °C
• Degrees above normal daily high temperature*: 12.2 °C

In seven cases, human-caused climate change made the heat waves much more likely to occur. This means that human influence on the climate made the following events at least two to 10 times more likely to happen:

Atlantic Canada (August 24 to 27)

• Peak daily high temperature during the heat wave: 23.9 °C
• Degrees above normal daily high temperature*: 6.7 °C

Eastern Ontario (July 31 to August 2)

• Peak daily high temperature during the heat wave: 29.2 °C
• Degrees above normal daily high temperature*: 5.8 °C

Fort Smith, Northwest Territories (August 8 to 13)

• Peak daily high temperature during the heat wave: 26.9 °C
• Degrees above normal daily high temperature*: 9.2 °C

Northern British Columbia (August 7 to 11)

• Peak daily high temperature during the heat wave: 23.6 °C
• Degrees above normal daily high temperature*: 7.0 °C

Northern Quebec (August 13 to 16)

• Peak daily high temperature during the heat wave: 23.6 °C
• Degrees above normal daily high temperature*: 7.8 °C

Southern Quebec (July 27 to August 3)

• Peak daily high temperature during the heat wave: 28.3 °C
• Degrees above normal daily high temperature*: 7.6 °C

Yukon (August 5 to 9)

• Peak daily high temperature during the heat wave: 24.1 °C
• Degrees above normal daily high temperature*: 8.9 °C

Finally, human-caused climate change made the following heat wave more likely to occur. This means that human influence on the climate made the following event at least one to two times more likely to happen.

Manitoba (July 30 to August 1)

• Peak daily high temperature during the heat wave: 28.3 °C
• Degrees above normal daily high temperature*: 6.4 °C

* The normal daily high temperature is an average over 1991–2020 of all of the region-averaged daily high temperatures in the month surrounding the event.

Prolonged heat waves are a major contributor to more intense wildfires across Canada. The 2023 wildfires in Canada burned almost 15 million hectares of forest and cost Canadians tens of billions of dollars in damages.¹ Understanding how human influence on the climate has increased the chance of a particular heat wave, soon after it occurs, can help inform adaptation strategies and heat wave response procedures for a changing climate while the event and its impacts are still top of mind. 

We urge the public 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.

Quick facts

• The Rapid Extreme Weather Event Attribution system is currently in its pilot stage. During this stage, the system will only analyze heat waves. Work to extend this system to analyze extreme cold temperature events and extreme precipitation is underway.
• As the planet continues to warm, we experience changes in the strength and frequency of extreme weather events. Human activities, mainly greenhouse gas emissions, are causing more extreme heat events, which can drive wildfires and drought; less extreme cold; shorter snow and ice-cover seasons; thinning glaciers; and thawing permafrost.
• Environment and Climate Change Canada is the country's official source for weather information and severe weather warnings and is committed to providing Canadians with accurate and timely weather information, including severe weather alerts.
• The latest forecasts and severe weather warnings are available through Environment and Climate Change Canada's weather website, the WeatherCAN app (available for Android and iOS devices), Weatheradio, and Hello Weather (1-833-794-3556).

Associated links

•         Extreme Weather Event Attribution

•         Environment and Climate Change Canada's Weather Information 

•         WeatherCAN App

•         Public Safety Canada – Get Prepared

•         Wildfire Smoke, Air Quality, and Your Health: Overview

•         Severe Weather  

•         Seasonal Weather Hazards

•         National Adaptation Strategy: Building Resilient Communities and a Strong Economy

Environment and Climate Change Canada's X (Twitter) page

Environment and Climate Change Canada's Facebook page

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¹ Jain, P., Barber, Q.E., Taylor, S.W. et al. Drivers and Impacts of the Record-Breaking 2023 Wildfire Season in Canada. Nature Communications 15, 6764 (2024). https://doi.org/10.1038/s41467-024-51154-7

SOURCE Environment and Climate Change Canada

Contacts Media Relations, Environment and Climate Change Canada, 819-938-3338 or 1-844-836-7799 (toll-free), [email protected]