Wildfires will worsen, experts forecast
Heat and drought. A longer fire season with more frequent wildfires and larger areas burned. That’s what’s in store for Canada — especially the Prairie Provinces — in the coming years, experts say, a situation that is being directly attributed to climate change.
In Canada, 2.5-million hectares — equivalent to about half the size of Nova Scotia — burn every year from wildfires, on average. The annual destruction has more than doubled since about the 1970s, when numbers were around one million hectares.
Current projections forecast even warmer, drier conditions across the country, creating the catalyst for more wildfires in the future.
“My colleagues and I attribute that to human-caused climate change. I can’t be any clearer than that,” said Mike Flannigan, professor with the Department of Renewable Resources at the University of Alberta.
“We’re seeing more fire because our climate is changing, in particular because it is getting warmer.”
And along with warmer temperatures comes an extended fire season.
“In Alberta, our fire season used to start April 1. It now officially starts March 1 and ... in the spring and winter of 2015-2016, we had actionable fires in February,” said Flannigan.
“The warmer it gets the more lightning we see and, everything else being equal, more lightning equals more fire.”
As wildfires become more frequent, the result is larger annual areas burned and an increase in the number of large fires, considered to be greater than 200 hectares in size.
“We’re already seeing it since the last 30 to 40 years. More recently, things like Fort McMurray, B.C. last year, B.C. this year and we’re seeing more impacts,” said Flannigan.
“Even if we stop producing greenhouse gases today, we will continue to warm for 50 to 100 years because there’s lags in our climate system.”
And Flannigan said those who call the situation a “new normal” are being overly optimistic.
“It sounds like it’s a plateau. But, actually, we’re on a trajectory, perhaps a downward spiral. Things could get a lot worse,” said Flannigan.
According to Marc-Andre Parisien, research scientist with Natural Resources Canada, climate change isn’t new and isn’t going away.
“There’s been a pretty significant increase in mean annual temperature in Alberta over the past 50 years,” said Parisien.
“The vegetation as a result is starting to change. A real telling example of that is dead trees .... You see a lot of dead trees and that’s from the series of droughts that we’ve had in the 2000s.”
The province is also expected to get even warmer in the coming decades.
“In the more pessimistic cases, some people are saying an increase of four to six (degrees),” said Parisien.
“I’ve even been seeing up to eight degrees Celsius, on average per year, in the next 80 to 100 years or so. That is huge.”
Although it is projected Alberta will also see more rain, Parisien said the moisture may not be able to keep up with the increased temperature.
“There’s this rule of thumb that with every degree in increased temperature, you need about 15 per cent relative humidity increase to keep up,” said Parisien.
“Any kind of increase in moisture, if there even is one, is really not keeping up with the increase in temperature, which leads to tree mortality and vegetation change.”
Those conditions create the perfect recipe for more wildfires in our future, he said.
“To put a value on it, it’s difficult. A lot of people have talked about it doubling or tripling,” said Parisien.
“It may not be as much as that but, definitely, the frequency of large fires, the probability large fires will occur, is greatly increased and it’s really strictly due to more days of hot, dry, windy weather.”
Alberta’s air-quality health index, established in 2011, measures three major pollutants: ozone, nitrogen dioxide and fine particulate matter.
“Fine particulate matter is very small particles that are small enough to be inhaled into the lungs and can cause a human health concern at certain concentrations,” said Bob Myrick, director of airshed sciences with Alberta Environment and Parks.
“The fine particulate matter is the main driver of the air-quality health index right now, and that’s what’s being associated with the wildfire smoke.”
Throughout the past week, the smoke from the B.C. wildfires has caused the index for Calgary to hover in the high to very high range, between 7 and 10+. Last week alone, the index reached 10+ three times, the highest possible rating.
The high levels and the large area those numbers covered this week, Myrick said, is very unusual.
“(Wednesday) we had numbers between 8, 9, 10 and over 10 between south of Calgary all the way to north of Edmonton. That’s a very large area and also it encompasses the major population of Alberta,” said Myrick.
“In fact, in my career — I’ve been working here for over 25 years — I haven’t seen that happen before.”
As wildfires are likely to become more frequent, Myrick said it’s difficult to predict whether we will see air quality further deteriorate, as the wildfires themselves depend on a number of factors.
Those include environment conditions, available fuel for the fire and whether they were caused by lightning strikes or were humancaused.
“One thing that I think we can say with a fair bit of confidence, is that wildfires will occur and they ’ll likely tend to be a significant part of our future, especially in the July, August time period,” said Myrick.