What to know
- A new Canadian Climate Institute report says climate change is making heat waves more frequent, longer-lasting and more intense, with prolonged heat events now nearly three times more common than in the 1950s.
- Researchers say Canada is warming twice as fast as the global average, while the Arctic is warming nearly four times faster, due to its geography and shrinking snow and ice cover.
- Extreme heat poses growing health risks, particularly for seniors, children, pregnant people and those with pre-existing conditions, with repeated exposure linked to long-term health impacts.
- Experts say reducing greenhouse gas emissions and investing in adaptation measures will be critical as cities like Toronto are projected to see far more days above 30°C by the 2050s.
Amid an ongoing Ontario heat wave, an updated climate change report suggests extreme heat is about to become more common in Canada, as the country warms up twice as fast as the global average.
Ontario residents are still feeling the heat, as the province has been under an orange Environment Canada heat warning for several days, with temperatures reaching close to the 40s.
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How does climate change impact heat waves?
With the warning now extended through Saturday, an updated report by the Canadian Climate Institute (CCI) is suggesting climate change is making extreme heat events hotter, longer, more widespread, and more frequent.
Zacharie Carriere, a research associate on the climate change adaptation team with the CCI, tells Now Toronto that evidence suggests long-lasting heat waves have become nearly three times more common than they were in the 1950s, as stalling weather patterns create what researchers call a “heat dome.”
“All that is is a weather pattern where high pressure kind of blocks the weather system in place, so if you can track really hot air over a big region, and it can last much longer because it’s not moving as much,” he explained.
“With climate change, on average, you’re getting hotter temperatures, so really that’s just like a stronger baseline for any extreme heat event to be even more powerful for the temperatures to reach greater heights.”
These “heat domes” mean the hotter temperatures last much longer and encompass a larger mass of land, meaning that heatwaves are not only more frequent, but also more widespread.
Heat waves come with significant health risks
According to Carriere, these more frequent heat waves come with significant health risks for residents, including increased cardiovascular events or respiratory conditions.
Some illnesses related to extreme heat include rashes, cramps, edema, fainting, fatigue, and heat stroke, according to the Government of Canada.
These symptoms are a risk to everybody, but represent an even greater risk for vulnerable populations, seniors, children, pregnant people, and those with pre-existing conditions.
“If you’re repeatedly exposed to high temperatures, that ages your body in a way that’s comparable to smoking. So, really, extreme heat just makes your body have to work much harder to stay cool, so it just puts physical stress on your entire body, and it leads to some long-term health consequences,” Carriere explained.
Under extreme heat conditions, Environment Canada advises residents to drink plenty of water, close blinds and shades, turn on air conditioning and fans, and seek cooler spaces. Residents should also watch out for heat stroke symptoms, including confusion, nausea, dizziness, changes in conscience and hot skin, and call 911 in case they notice them.
Canada’s warming up twice as fast as global average
The CCI report also suggests that Canada is warming up twice as fast as the global average, while its Arctic region is warming up nearly four times as fast.
Carriere explained that there are two main possible reasons for the faster warming.
While large bodies of water such as oceans or lakes are known for absorbing the heat and slowing down this warming, Canada misses on this cooling effect for being a country with a large landmass.
“There’s a lot greater surface area that will warm faster that’s not being moderated by the influence of oceans, so if you look across the country, the central areas of the country are generally warming faster,” he explained.
In addition, he explained that the Arctic snow also had this cooling effect, and it reflects the heat back and keeps the surface from getting warmer. But as this snow begins to melt more, more dark land surface is exposed, leading to the opposite effect.
For Canadians, this means more frequent and longer heat waves.
According to Carriere, evidence suggests Toronto is projected to have roughly three times as many 30ºC-plus days compared to the historical average by the 2050s.
In Toronto for instance, Carriere said evidence points
Can we slow this down?
As mentioned by Carriere, most extreme heat events are driven by climate change. Hence, to slow down the warming, he said the government should put in efforts to address the roots of climate change.
“In Canada, and everywhere around the world, we need to reduce our emissions. We need to look for wherever it’s cost effective to bring in renewable energy,” he suggested.
In addition, the researcher pointed out that all three levels of government should be working on solutions to mitigate the effects of warmer days for residents, including introducing cooling centres, planting trees to reduce the urban heat island effect, or making grants available for low-income residents to buy air conditioners or heat pumps.
“There’s still a huge gap that needs to be filled, so I think we’re kind of in a stage where governments know that this is a growing problem, but there’s a lot more investment that needs to be done,” he added.
