This July’s scorching heat waves were made up to 10 times more likely due to climate change, reports Environment Canada.
Environment Canada issued a report from its Rapid Extreme Weather Event Attribution system Aug. 13 on heat waves that happened in western Canada in July 2024. In Alberta, the study applied to the July 7-11 and July 16-23 heat waves.
Environment Canada launched this new system last March to more rapidly explain how human-caused global heating/climate change affects extreme weather such as heat waves, said Environment Canada research scientist Nathan Gillett.
Gillett said the system uses climate models to compare the odds of any one heat wave happening in today’s climate (which is undergoing rapid change due to human-caused greenhouse gas emissions) compared to the pre-industrial 1800s. This most recent analysis found that human-caused climate change made the July heat waves in Alberta at least two to 10 times more likely to have occurred.
Real impacts
Those heat waves had substantial impacts on St. Albert. The Gazette’s archives show that the city set a new daily heat record of 32.6 C on July 8. City officials activated their extreme weather response plan during both waves, which saw buses and St. Albert Place opened to the public as cooling shelters. The heat led to the cancellation of public events such as the July 10 Weed Warriors weed pull and prompted a flood of calls to air conditioner installers such as A1 Heating & Cooling. City of St. Albert senior utilities manager Regan Lefebvre said the second heat wave sent water demand soaring, prompting the city to bring in water restrictions from July 22-25.
Greenhouse gases released by human activities trap heat and have warmed Canada’s climate by about 2 C since pre-industrial times, Gillett said.
“That general warming of the climate means those hot extremes, those particularly hot days, become more likely to happen."
That second heat wave corresponded with the wildfire that damaged or destroyed about 30 per cent of Jasper. Wildfire experts have cited the heat wave as a contributing factor to the fire’s intensity.
“Warming and climate change increase the risk of wildfire because it dries out the forest more quickly,” Gillett said, adding that he had yet to study the role of climate change in the Jasper wildfire specifically.
Gillett said attribution studies such as this one can help Canadians understand and adapt to the impacts of climate change. Knowing that the 2021 floods in B.C. were made more likely by global heating could prompt planners to build bigger bridges, for example.
Global heating means St. Albert will likely see a 700 per cent increase in heat waves by the 2060s (3.2 a year compared to the 1976-2005 average of 0.4), the St. Albert Climate Adaptation Plan reports. (A heat wave is any period of at least three consecutive days of at least 30 C weather.) Said waves are projected to last about 373 per cent longer, or about 5.2 days instead of 1.1.
St. Albert renewable energy expert Leigh Bond said fans, heat pumps, and better insulation can help homeowners prepare for future heat waves. He called on the city to better promote its Clean Energy Improvement Program (CEIP) as a way to fund such improvements.
Gillett said researchers plan to use the attribution system to study extreme cold and precipitation events in the months ahead.
Visit bit.ly/4cjI77u for more on the Rapid Extreme Weather Event Attribution system.
