Five charts to help understand Canada’s record-breaking wildfire season

It has been months since Canada surpassed the record for the worst wildfire season in recorded history in terms of area burned. Since June 27, to be exact. And some fires are still burning.

Here’s an overview of the unprecedented season and what it means for the future of Canada’s forests.

Total area burned

The first chart outlines a key measure — the area burned. 

That’s the record that was broken nearly four months ago. The total area burned has now exceeded 18 million hectares, which is two and a half times the previous record set in 1995 and more than six times the average over the past 10 years.

“I would say we’ve crossed a tipping point. This summer across Canada has been absolutely astounding in terms of wildfire,” said Lori Daniels, a professor in the department of forest and conservation sciences at the University of British Columbia.

“These are the types of fires that I think will be ecosystem changing. It will take decades to centuries for those ecosystems to recover, if they recover, given the confounding influence of climate change.”

Fire weather

What led to all these fires? In short, it was hot — very hot. Across the globe, it was the hottest summer on record. 

The hot, dry weather in Canada, especially in northern regions, was ideal for wildfires.

The map that follows shows what’s known as the Fire Weather Index (FWI), which measures the dryness of the forest (known as fuel), along with the temperature, humidity, level of precipitation and wind speed.

Overall, the FWI far exceeded the norm in nearly the entire country. The trend was clear early on in May, when northern Canada was the epicentre of a heat event, Daniels said. 

“We were 10 to 15 degrees Celsius above normal in northern Canada, which again primes these [areas] for fire,” she said.

Yan Boulanger, a research scientist at Natural Resources Canada, said what he finds most striking is how long the season has dragged on, and how early it began.

“It began in early May, and it never stopped till the end of September,” he said, noting some fires are still burning.

Boulanger was part of a team of international scientists that studied the wildfire season in Quebec, and found that climate change made the weather conditions that drove the wildfires two times more likely. 

Total number of fires

In Canada, roughly half of all wildfires are caused by lightning. The other half are caused by human activity. 

Despite the record-setting season, there has not been a marked increase in the total number of fires, as the next chart shows. (There have been more than last year, but around the same number as the year prior.) 

The dry, windy weather helped spread fires quickly, Daniels said, and in many cases they burned for months.

“Once a fire is burning under those hot, dry, windy conditions and gets momentum, it builds on that momentum,” she said. 

“It generates its own energy. It generates its own weather system. And so that helps to maintain the high intensity.”

Where the fires happened

This next map illustrates that point — demonstrating the parts of the country that saw the most fire this year.

The map is especially striking when compared to last year, when fewer areas burned. 

According to Boulanger, the impacts on everything from wildlife to the forestry industry will be wide ranging. 

“There will be huge impacts on the forest sector,” he said. 

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Source of emissions

The wildfires also produced smoke that resulted in dangerous air quality in cities across North America and beyond. 

The greenhouse gases unleashed by the fires far surpassed those produced by all sectors in the Canadian economy combined, according to Copernicus Atmosphere Monitoring Service, a European agency.

Canada’s boreal forest has long served as a carbon sink — absorbing and storing carbon from the atmosphere — but this year, Daniels says that because of the fires, it became a source of carbon, releasing more than it stores. 

“These local fires have global impacts and implications, and that’s really disconcerting because that positive feedback will contribute to more warming which will make us increasingly susceptible to fire,” she said.

Wildfire experts, including Daniels, are concerned that the recent arrival of El Niño could mean another hot summer and difficult wildfire season in 2024.