More heat, drought and longer fire season in Canada’s future, experts say

Photo: calgaryherald

 

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, where numbers were around one million hectares.

Current projections forecast even warmer, drier conditions across the country, creating the perfect 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 the warmer the temperature comes an extended fire season.

“In Alberta, our fire season used to start April 1. It now officially starts March 1 and not this spring, but in the spring and winter of 2015/2016, we had actionable fires in February,” said Flannigan.

Natural Resources Canada graphic showing the change in projected fire season start dates. NATURAL RESOURCES CANADA

“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.”

Flannigan said the reality is fire is a part of our future and a term people often use is this is our “new normal,” but he doesn’t like the use of it.

“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.

ALBERTA’S SITUATION

According to Marc-André Parisien, research scientist with Natural Resources Canada, a federal agency, climate change isn’t something exclusively for the future, it’s happening right now and we can see the effects.

“There’s been a pretty significant increase in mean annual temperature in Alberta over the last 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 tree and that’s from the series of droughts that we’ve had in the 2000s.”

The province is also expected to get warmer in the coming decades.

“In the more pessimistic (climate scenario) 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 that Alberta will also see more rain, Parisien said the moisture may or may not be able to keep up with the increased temperature. He said that’s looking like this is the case right now.

“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 of large fires will occur, is greatly increased and it’s really strictly due to more days of hot, dry, windy weather.”

POOR AIR QUALITY

The air quality in Calgary could reach at 10+ on the ranking scale this week. LEAH HENNEL / POSTMEDIA
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 week, the smoke from the B.C. wildfires has caused the AQHI for Calgary to hover in the high to very high range, between 7 and 10+. This week alone, the AQHI reached a 10+ three times, the highest possible rating.

To quantify what exactly being in the 10+ range means, Myrick used the 2016 Fort McMurray wildfire as an example.

“Fort McMurray two years ago, we had levels of these fine particulate matter that were up in the thousands in terms of the concentration. Normal values are between 10 and 20 micrograms. We had huge numbers,” said Myrick.

The high levels of the AQHI and the large area those numbers covered seen this week, Myrick said, is very unusual and does not happen often.

“(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, so the fact that we had very high air quality health index and the fact that we had it over such a large area was quite unusual.”

As wildfires are likely to become more frequent, Myrick said it’s difficult to predict whether we will see the AQHI hitting the higher range, 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 human-caused.

“One thing is 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.

FUTURE ADVERSE HEALTH EFFECTS?

The long-term effects of breathing in smoke from wildfires is still unknown and Chris Carlsten, a respirologist at the University of British Columbia, said while the short-term effects are concerning, it is important to consider the upward trend of wildfire frequency.

“These have been such temporary events that we have thought of the adverse effects as short-term, but as they get longer, we start to blur the lines between acute and chronic,” said Carlsten.

“It’s not chronic yet in terms of year-round. When you start to get into weeks and possibly months, it becomes an open question as to whether these events will be associated with acute or chronic effects.”

Carlsten said we’re not at the point at chronic effects yet, but he is concerned with the frequency, duration and intensity of the wildfires.

“If these (wildfire) seasons become July, August, September, then you’re taking about 25 per cent of the year, and who knows — I don’t want to be alarmist. The trend is not good,” said Carlsten.

If the air quality worsens, Carlsten said a potential scenario is normally healthy people developing a chronic illness where there wasn’t one before.

“If you’re getting repeated hits (of smoky air) and it’s three months then, theoretically, gradually, people will be more likely to develop more (chronic health issues) that won’t go away because the longer we are exposed, and the less clean (air) time, the harder is it is to repair these inflammatory insults.

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