‘This is a wake-up call’: Canada heatwave a sign of uncertain years to come, scientists warn

Canada’s record-breaking heatwave could accelerate glacial melt and permafrost thaw, increase flooding and wildfires, and mean more rocketing temperatures for years to come, scientists have warned.

Temperatures hit 121.1F (49.5C) in Lytton, British Columbia, on Tuesday – the third day in a row on which Canada’s all-time highest temperature was superseded.

Meteorologists say the unprecedented conditions are being caused by a “heat dome” over western Canada and parts of the US Pacific northwest.

“Heat dome” is an unofficial term for an area of hot air high up in the atmosphere which lingers over an area for a prolonged period of time, trapping in heat below.

The extreme heat is believed to have contributed to dozens of “sudden deaths” in western Canada, with death tolls expected to rise. Meanwhile two large wildfires are burning uncontrolled in the region, forcing the evacuation of homes.

Brett Anderson, senior meteorologist at AccuWeather, says that in his 32-year career he has never seen a heatwave across the Pacific northwest that has “even come close to what we have seen over the past several days”.

“[We] knew that some all-time highs may be in jeopardy of falling, but they did not just get broken, they were obliterated,” he tells The Independent.

While the heat dome was a unique weather event that relied on unnatural atmospheric conditions, scientists warn that the role of global warming in the heatwave cannot be discounted.

“This is unequivocally a signal of climate change,” says Joseph Shea, a professor of environmental geomatics at the University of Northern British Columbia.

“This type of extreme heat event is just a very logical consequence of small increases in the average global temperature.”

Warnings of rising temperatures and extreme weather events in Canada have been sounded by meteorologists and scientists for “decades”, Shea says, so the country should have been better prepared to cope.

In 2019, a report commissioned by Environment and Climate Change Canada found the country was warming at twice the global rate, with the highest rates occurring in the north, the Prairies, and northern British Columbia.

“We do flood forecasting in the spring, as the snow melt starts to happen in the mountain rivers, and in places where we expected floods, we sandbag and we protect and evacuate communities. This is forecast in advance. This heatwave was forecast. And nothing was really done,” continues Shea.

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Few Canadian houses have air conditioning, Shea says, as many were built to “withstand the cold, not the heat”, with thick insulation and little air flow. This leaves vulnerable and disadvantaged people at severe risk of health complications due to the heat.

Vancouver Police say that they have responded to more than 65 “sudden deaths” since the heatwave began on Friday.

Shea says he expects the death toll to rise in coming days, and to be primarily made up of seniors who were unable to leave their homes.

“This is the hardest part about climate change; it always affect marginalised, less fortunate communities more,” he says.

The early onset of the heatwave, in a month that is typically known for being cloudy and mild in temperature, means more extreme weather events could be in store for the remainder of the Canadian summer.

Wildfires could become more widespread as the fires currently raging across British Columbia dry the forests at a more rapid pace. It is also likely to affect snow packs and glaciers, accelerating their annual melt.

“The rivers in the west are going crazy right now. There’s so much snow coming off the high alpine snow fields and glaciers very early in the season. So the glaciers are not going to have a happy year this year. They’re just going to be exposed to melt for the rest of the summer,” says Shea.

The heat wave has coincided with the passing of the Canadian government’s Bill C-12 on Tuesday, which requires Ottawa to set rolling, five-year targets to cut greenhouse gas emissions between 2030 and 2050, with an eventual goal of zero emissions by 2050.

Professor of climatology at the University of British Columbia, Simon Donner, says this is a step in the right direction to combat similar extreme weather events in the coming years, but that the Canadian public needs to speak up more to demand stronger federal action on climate change.

While scientists disagree on whether an increased prevalence of heat domes could be directly attributable to climate change, Donner says there is “strong evidence” that similar events will increase in the future, “in a planet warmed by greenhouse gases”.

“These types of numbers we’re seeing will become more common. We’re not going to break a record every week or every year. But we’re going to have more and more warm weather events.”

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Despite heatwaves “not being on our radar before this”, Shea says, they are likely to become more severe and more frequent in years to come. This brings to the fore wider concerns, such as the thawing of permafrost in the Arctic region, which leads to erosion and emissions of methane into the atmosphere.

Rising river temperatures raise questions about fish life, specifically salmon habitats. Flooding could also worsen in urban areas such as Toronto, as a result of severe thunderstorms.

“Our cities and our infrastructure have been designed for a climate that no longer exists,” Shea says.

“This is a wake-up call. This heatwave is something that is going to have a huge toll on human lives.”