Climate change made NWT’s fire season twice as likely to occur, report finds

A report from World Weather Attribution says climate change is making the month of fire weather leading up to this year’s NWT fire season far more likely to occur.

The report, titled Climate change means extreme fire seasons in Canada are here to stay, used observation-based data and climate models of the most severe month and week of fire weather in the NWT and northwestern Ontario to analyze this summer’s wildfire probability.

In the NWT, the current rise of global temperatures by 1.4C was shown to have increased the likelihood of extreme seven-day periods of fire weather five fold, while rising temperatures have have meant that longer term periods of extreme fire weather have become about twice as likely.

The potential effects of fire weather are calculated using the Fire Weather Index System. This system predicts how fire will behave under certain temperature, relative humidity, wind speed and rain conditions, and wildland firefighters use the Fire Weather Index value to plan firefighting actions.

“Since 2023, the wildfires we’ve seen across Canada have been fundamentally different in
their scale and intensity,” Theodore Keeping, a co-author of the report and a research associate at Imperial College London was quoted as saying in a Wednesday news release.

“This year is a continuation of that trend in two regions. The Northwest Territories have shown fire activity equivalent to the worst year on record for the time of year.”

On Wednesday, the World Weather Attribution held a media briefing with co-authors of the report to explain their findings.

Jonathan Boucher, a co-author and a wildland fire research scientist with Natural Resources Canada, said the NWT saw extreme fire weather this year, with Fort Simpson experiencing its highest ever Fire Weather Index value for July since the 1990s.

The community spent nearly three weeks under an evacuation order this summer because of wildfires, while residents of the neighbouring Wrigley were out of their homes for a month.

Boucher said this summer’s fires burned at a relatively rapid rate in the two jurisdictions.

“As of now, as our latest numbers [show], just above 90 percent of the area burned had burned in a few weeks in late June and July,” said Boucher.

While the NWT has seen non-exceptional data when it comes to the number of fires in the territory or the area burned this year so far, Ontario has seen the most area burned in the province’s recent history, affecting more than 730,000 hectares, Boucher said.

The report noted more extreme fire seasons are becoming more taxing on the resources needed to help tackle blazes.

Wildfires are also having greater public health implications, particularly when combining the effects of wildfire smoke and extreme heat, the report said.

“We know that the impacts of wildfires reach far beyond the location of the fire itself. Smoke from these fires have affected millions of people across over hundreds of kilometres, this can cause severe and often delayed health impacts related to air pollution,” said Chris Boyer a co-author of the report and the technical advisor of climate and health at the Red Cross Red Crescent Climate Centre.

“These effects are even more pronounced among populations with compounding vulnerabilities, such as pre-existing health conditions or lower socio-economic status.”

Boyer said research indicates the wildfires studied over the summer disproportionately affect Indigenous communities.

“Some of these communities [are] also dealing with the shortened response and recovery times between disasters due to the recent successive wildfires affecting longer term resilience,” said Boyer.

The authors of the report said they hope the study can be used to help inform public policy.

“Of course climate change is not acting in a in a vacuum,” said Friederike Otto, a co-author and a professor of climate science at Imperial College London.

“It’s acting in a society where lots of people are differently vulnerable and differently exposed, but also that means on a local level – on different levels – there’s a lot that you can do to be better protected and to be better adapted.”