Western Canada's heat wave is 'unprecedented.' Scientists say it will become more common with climate change - CBC.ca

Smoky skies. Polluted air. Sweltering heat. 

During three of the past five summers, British Columbians have endured extreme weather events, rewriting a season long known for its mild, sunny forecasts. 

This week's historic heat wave, which unleashed punishing temperatures on the Pacific Northwest and is now moving eastward to Alberta, has brought the realities of climate change into even sharper relief.

Climate scientists are cautious about citing climate change as the cause of any specific weather event. But some say evidence suggests extreme events are intensifying and becoming more common because of global warming.

"I'm shocked by this," said Simon Donner, a professor of climatology at the University of British Columbia. 

"As a climate scientist, we expect to see more extreme heat waves going forward into the future because we're adding greenhouse gases to the atmosphere. But this is even beyond my expectations. To have a heat wave last this long and be this hot in Canada is completely unprecedented in history."

'It really feels like dangerous heat'

The village of Lytton in B.C.'s Interior shattered Canada's all-time weather record over three consecutive days, surpassing an eye-popping 49 C on Tuesday. B.C.s Fraser Valley recorded temperatures in the mid 40s. Vancouver, which usually benefits from cool ocean air, recorded an overnight low of 24 C on Monday night, the type of heat often felt in the tropics. 

"There's something that feels a bit different about this one and I can't quite put my finger on it," said Joseph Shea, a professor of environmental geomatics at the University of Northern British Columbia.

"I was trying to come up with a word on the weekend and I think the word is menacing. It really feels like dangerous heat."

WATCH | The 'heat dome' explained:

David Phillips, senior climatologist for Environment Canada, says the high-pressure heat dome over parts of Western Canada creates an effect that's like 'putting a lid on boiling water.' 3:52

The global temperature has increased by 1.2 C since industrialization, according to the World Meteorological Organization. A 2019 report commissioned by Environment and Climate Change Canada found Canada is warming twice as fast, with the highest rates occurring in the North, the Prairies and northern British Columbia. And temperatures in the Arctic are increasing three times the global rate. 

"That doesn't sound like very much, but it shifts the whole system. And so when you get big spikes, they get higher," said Deborah Hartford, executive director of Adaptation to Climate Change, a policy planning initiative at Simon Fraser University. 

CBC metereologist Johanna Wagstaffe said jet streams — which essentially move weather patterns — are stalling much longer due to the shrinking temperature difference between the Arctic and mid-latitudes. 

"You get great waves, like what's happening over B.C., that stick around for longer," she said. 

B.C. vulnerable to extreme weather

The heat wave has also underscored how British Columbians have yet to adapt to the changing climate conditions and are vulnerable to its impacts.

Roughly one-third of B.C. residents use air conditioning, according to a B.C. Hydro survey from last year, with the number jumping to 72 per cent in the southern Interior. 

The heat wave, which came with only days of warning, saw stores in B.C. sell out of air conditioners and fans. Hotels in Vancouver were fully booked Monday, drawing locals desperate for escape. Police in Metro Vancouver said Tuesday they had responded to more than 100 sudden deaths since the heat wave took hold. 

WATCH | Vancouver doctor explains what he's seeing during the heat wave:

Vancouver emergency room physician Dr. Daniel Kalla on the precautions, warning signs and potential remedies for heat-related illnesses as temperatures reach record highs, and how to cool down. 2:26

Record overnight temperatures made matters worse, with a low of 22 C in Victoria on Monday — close to the typical daytime high for that time of year. 

"We need those evenings to recover from the hot days that we experience," said Faron Anslow, a climatologist with the Pacific Climate Impacts Consortium in Victoria. 

While the heat wave was unusual in its intensity, Wagstaffe anticipates B.C.'s baseline will shift in the coming years. 

"We'll see more days, over 30 degrees. We'll see way more days, over 20 degrees," she said.

"And we'll really start to notice a change in our seasons. We'll see the extreme weather events like fires and severe storms and flooding start earlier and last later." 

Mountaintops that never melt are thawing as a result of the heat wave, Wagstaffe said, raising questions about flood risk and the impact on water reserves through the summer and into the early fall. 

The wildfire risk also looms large. Forests are drying out and are rapidly turning into tinder for when a lightning storm strikes or a cigarette is tossed. 

"I think we've all learned in the past few years, the forest fire doesn't have to be anywhere near your home for you to be affected by it," Donner said.

What next?

While British Columbians have grown accustomed to wildfires, the severity of the heat wave has renewed awareness around the climate emergency. 

"I've covered a lot of weather events that have been connected to climate change," Wagstaffe said. 

"And I've got to be honest, I think this one is the one that really made me consider my future and my two-year-old old's future. We were literally trying to think of an emergency plan for the forecast that had heat that would be too dangerous for my family to be in our own home." 

Shea said the only way to stop climate change is to stop pumping emissions into the atmosphere. 

"It's simple to say that but very hard to do because of the systems we have in place," he said. "At this point, there's nothing else we can do except really make that push." 

The Paris climate agreement aims to keep the global temperature increases this century below 2 C — and ideally 1.5 C — to stave off the worst effects of climate change.

A construction worker uses a misting fan to cool down at a work site in Vancouver on Monday. Vancouver police say they have responded to more than 100 sudden deaths since the heat wave took hold. (Ben Nelms/CBC)

Anslow said change on a personal level can mean reducing your emissions by curtailing vehicle use, reconsidering what you eat and cutting down on energy use at home. 

"These all will seem like pretty small drops in the bucket when you're doing them, but they do add up," he said. 

Donner said people need to push their politicians for stronger action, such as regulations around electric vehicles and energy-efficient homes and buildings. 

"This is not the new normal," Donner said. 

"There's going to continue being new normals until we stop emitting greenhouse gases because the baseline, or what we think of as normal, is constantly moving upwards now." 

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Western Canada's heat wave is 'unprecedented.' Scientists say it will become more common with climate change - CBC.ca
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