Here's how many 'risky heat' days climate change added to our summer this year
Did it feel like an unusually hot summer? This year, thanks to climate change, Canadians experienced a lot more days hot enough to put their health at risk. A new analysis counts exactly how many.
A report released Wednesday by the non-profit group Climate Central shows that from June to August, the average Canadian experienced 13 extra "risky heat" days, thanks to climate change.
The analysis defines those as days when the temperature is hotter than 90 per cent of local temperatures between 1991 and 2020.
The organization researches and reports on climate change impacts and solutions, and does this kind of summer heat analysis twice a year for cities around the globe. The global report found that many areas of the world were far worse than Canada, with 955 million people worldwide experiencing an extra 30 days or more of "risky heat" due to climate change.
The exact "risky heat" temperature can vary widely between cities that normally have cooler summers, such as Vancouver, and those that normally have hotter summers, such as Windsor, Ont. The threshold is when vulnerable people such as older adults start to experience health problems, said Kristina Dahl, vice-president of science for Climate Central, because people tend to adapt to their local environment.
There were deadly this summer heat waves in both in Canada and in Europe, where a recent study estimated that a heat wave between June 23 and July 2 killed 1,500 people.
Dahl added that heat waves can also lead to indirect risks, such as smoke from wildfires. The smoke pollutes the air, "which is closely tied to premature deaths," she said. "The reality is those increased temperatures play out in many, many ways."
This year was Canada's second worst wildfire season on record. A recent study estimates that Canadian wildfire smoke caused 82,000 premature deaths in 2023.
There are some extreme heat days every summer. But by using climate models to compare this year's temperatures with what would be expected without climate change, the new analysis shows just how many more "risky heat" days occur across the country and around the world. That's despite the fact that average global temperatures have increased only about 1.4 C since preindustrial times.
'A reality of the near future'Environment Canada also released a rapid analysis Wednesday of 12 heat waves in Canada this summer. For 11 of them — in the west and in Quebec — it found heat waves of that magnitude were twice as likely due to climate change. A heat wave like the last one, in Atlantic Canada from Aug. 7 to 14, was 10 times more likely due to climate change.
Hossein Bonakdari, an associate professor of civil engineering at the University of Ottawa, says the message is clear.
"Climate change is reshaping the odds of daily weather in Canada, and people feel it most directly through extreme heat," he said.
Bonakdari, who uses AI to study the risks of climate change, says his model shows that, in 20 years, average temperatures across Canada will be 1.8 to 3.2 C hotter than they would be without climate change.
"This is… a reality of the near future," he said. "I'm not talking about end of century right now. I'm talking about the next 20 years and we need to be prepared."
Jennifer Vanos, an associate professor at the School of Sustainability at Arizona State University, says many people are already experiencing extreme heat.
"We really need to start making changes now versus only worrying about the future," she said.
That could include making air conditioning more available, having policies to ensure people with outdoor jobs can get out of the heat, and community services to help those in dangerous situations due to heat, she says.
Dahl agrees that the report shows climate change is no longer a future threat, and suggests more efforts are needed to cut fossil fuel emissions.
"Every delay in reducing emissions means more communities, ecosystems, and economies will suffer," she said.
cbc.ca
