Environment and Climate Change Canada (ECCC) has published the most recent results from the country’s Rapid Extreme Weather Event Attribution system, showing that human-caused climate change made some heatwaves this summer 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 heatwave,” they state. “In all cases, human-caused climate change made heatwaves in August 2024 more likely to have occurred. In some instances, it was at least 10 times more likely.” 

Of the 11 events analyzed, ECCC says three events were at least 10 times more likely to have happened today, thanks to climate change, than would have been the case in the pre-industrial model. In seven cases the events were between two and 10 times more likely to have occurred, while just one event was one to two times more likely to have occurred because of changing climate patterns. 

Major contributor to wildfires 

“Prolonged heatwaves are a major contributor to more intense wildfires across Canada,” they write. “Understanding how human influence on the climate has increased the chance of a particular heatwave, soon after it occurs, can help inform adaptation strategies and heatwave response procedures for a changing climate while the event and its impacts are still top of mind.” 

The Canadian weather attribution system is currently in its pilot stage. “During this stage, the system will only analyze heatwaves. Work to extend this system to analyze extreme cold temperature events and extreme precipitation is underway.”