Heat wave: As B.C. bakes, what role does climate change play?

Click to play video: 'Health officials warn about risks of coming ‘heat dome’'
Health officials warn about risks of coming ‘heat dome’
WATCH: With a 'heat dome' bringing temperatures into the forties in some parts of B.C., health officials are urging people to put safety first. We have full coverage from reporter Kylie Stanton and meteorologist Kristi Gordon. – Jun 24, 2021

British Columbia is baking under extreme heat, with forecasts predicting the worst is yet to come.

The unseasonably hot weather has many asking whether the heat wave can be attributed to climate change.

Climatologists are wary of trying to attribute any specific extreme weather event to climate change — though the evolving field of event attribution is beginning to change that.

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But there is wide agreement among scientists that there are links between the changing climate and the frequency and severity of extreme weather events.

“We know with great certainty that warmer temperatures come with climate change,” Faron Anslow, climate analysis and monitoring lead with the Pacific Climate Impacts Consortium (PCIC), told Global News.

Click to play video: 'Increased concern for drought and wildfires in B.C. this summer and climate change is playing a role'
Increased concern for drought and wildfires in B.C. this summer and climate change is playing a role

“So to start off with you can kind of picture this background temperature warming, and then you add a hot event like this and you’re already that much closer to those all time highs under the same conditions.”

Average annual temperatures have climbed in British Columbia in recent decades, according to the data.

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National Resources Canada’s 2019 Canada’s Changing Climate Report, found both the mean annual temperatures in the province rose by 1.9 C between 1948 and 2016. The mean summer temperature climbed 1.7 C, while winter temperatures were up by 3.7 C.

“Extreme temperature changes (in Canada), both in observations and future projections, are consistent with warming,” the report states. “Extreme warm temperatures have become hotter, while extreme cold temperatures have become less cold.”

Data from the government of British Columbia found annual maximum temperatures have climbed by 0.7 C in the last century, while annual minimum temperatures were up by an average of 2 C.

“It’s what we can expect with climate change. So as the climate continues to warm, which we have plenty of evidence that’s going to be the case, we’re going to see more events like this,” Anslow said.

A hotter future

According to the International Panel on Climate Change, global temperatures must be held to 1.5 C above pre-industrial levels — the aggressive goal of the Paris Agreement — in order to avoid the worst impacts of climate change.

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Temperatures have already risen by 1 C, according to the IPCC, and are projected to reach 1.5 C as early as 2030.

Missing that target, according to the NRCC’s modelling, could have clear impacts for temperatures in B.C. in the future that vary drastically by how much the Earth warms.

The NRCC report projected that missing the target but keeping temperatures under 2 C — still an aggressive target, but seen as a crucial tipping point by the IPCC — could see B.C.’s annual highest temperature climb by another 1.7 C.

It could also come with an annual average increase of about 1.6 hot days by by 2031-2050 — with little change by 2081-2100.

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Climate change activist shut down major Vancouver roadways

But under a scenario where carbon emissions continue to rise at their current pace, annual maximum temperatures could spike by 2.3 C by 2031-2050, and as high as 6.7 C by 2081-2100, according to the NRCC.

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The number of hot days in an average year could climb by 2.5 in 2031-2050, and by a staggering 16 by 2019-2100, under that scenario.

Under the below-2 C scenario nationally, what was once a one-in-50-year heat event is projected to become a one-in-10-year event, while a what was a one-in-five-year heat event could be something Canadians see every five year, it found.

The PCIC also looked at the “business as usual” scenario for its own 2017 report to Metro Vancouver, projecting an average temperature increase of 3.7 C for the Lower Mainland by 2050, and hike of 6 C by 2080.

That same model projected a 19 per cent drop in summer rain by 2050, rising to 29 per cent by 2080.

“The number of these hot days where the temperature is above 30 degrees is going to go up quite rapidly,” Anslow said.

“So locations where you have maybe 10 days where it’s this hot, it’s going to go up to twice that number or even more in the next 50 years or so.”

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