What's causing Canada's raging wildfires? It's not as simple as blaming climate change, expert says
Warming temperatures play a role, but there is a core difference between this year's eastern and western fires
Experts are warning that Canada will face its more severe year of wildfires.
So far, tens of thousands of people have been evacuated and government data shared Monday showed that 413 fires across several provinces and the North were burning as of Sunday afternoon. About 26,206 people are under evacuation orders in British Columbia, Alberta, Saskatchewan, Quebec, Nova Scotia and Northwest Territories.
Cities across Eastern North America are currently being impacted by hazy smoke and poor air quality as forest fires burn in provinces like Quebec and Nova Scotia.
While wildfire seasons are predictable in warmer months across Western Canada, this season has started earlier than it normally would, and in places not typically known for such events.
While it may seem obvious to blame climate change for these extreme conditions, one expert clarifies that there’s more factors at play.
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What causes wildfires?
Kent Moore, Professor of Physics at the University of Toronto, says forest fires are regular occurrences, particularly in the west. Generally, fires have been been an “out of sight, out of mind” situation, especially if they aren’t impacting populated regions. However, when thousands of people become displaced, like the 2016 Fort McMurray fires, people start to pay attention.
“What we’re seeing now, especially in Nova Scotia, is there’s fire on the outskirts of a major metropolitan area, and people having to evacuate,” he tells Yahoo News Canada. “It’s different from what we normally see. Plus, the poor air quality across most of Eastern North America from the Quebec fires, you’re feeling the impact.”
There are a few reasons as to why fires start in the first place. They're usually ignited as a result of lightning strikes, combined with dry conditions, or they’re started by humans, or human-related activities - like an ATV driving along grass or the spark of an engine.
It's not all climate change: East vs. west fires have different causes
In western provinces, there was an early spring heatwave, which is rare, and Moore says it’s an indication that the climate is changing.
While we focus on temperature, the seasons change too, so spring is coming earlier now than it used to. One of the challenges is the ecosystem, plants and animals, have evolved over hundreds of thousands of years to expect a certain kind of climate. They expect spring to come at a certain time of year, and if spring’s coming earlier, then the vegetation hasn’t caught up with it.Kent Moore, Professor of Physics at University of Toronto
Western Canada’s early spring came when the vegetation hadn’t yet started to green up in the forest, which resulted in more fuel that contributed to the wildfires.
In Nova Scotia, very dry conditions lead to a greater burn. Moore explains that typically if a fire starts going in the spring, it's just the surface that burns because the ground is still wet even as the vegetation is dry.
Because the ground was so dry from the winter and the spring, fires in the province got into the ground, and that lead to more organic matter in the ground burning.
“Those are much more difficult to put out because you have to dig up the dirt to get to the fire,” Moore explains. “That’s typically what you’d find in the summer fire season, when things tend to be drier.”
Quebec is experiencing a similar situation, with dry climate leading to more fires. As a result, Moore doesn’t believe the fires in the eastern provinces are a direct result of climate change, but rather a dry season.
“There’s just natural variability,” he says. “Some springs are dry and some springs are wet."
How climate changes plays a part
That’s not to say climate change isn’t a factor. Moore says the planet has warmed up by 1 degree on average - in the northern latitudes, it’s probably closer to 2 to 4 degrees, which is leading to warmer conditions that contribute to wildfires.
“Wildfires like heat, they like dry hot conditions,” he says. “So if the average has warmed up by 4 degrees then the extremes will have probably gone up by double that. Extreme temperatures will be 8 degrees higher than they were in the past and these extreme conditions can get these fires going and help them propagate.”
Additionally, there is risk to expanding developments where we chose to live. If a floodplain is built on, for example, then an evacuation as a result of a flood is part of that reality. The same goes for fires.
“If you choose to live in an area that is forested, then there’s a potential for fire and one has to deal with that,” says Moore.
What we consider extreme conditions also continues to evolve and intensify. What was extreme weather 30 years ago is considered more normal today. And that's important to consider when building infrastructure.
“Bridges that have been built to withstand a 100 year event collapse, because a 100-year event is now a 20-year event,” says Moore.
We see the extremes becoming more extreme and we have to harden our infrastructure to deal with the fact that extremes are becoming more extreme. What used to be a normal situation is no longer that case. So we have to understand that there’s a need to harden our infrastructure as well.Kent Moore, Professor of Physics, University of Toronto
