A helicopter dumps a load of water on the Philpot Road fire outside of Kelowna, B.C., Monday, August 28, 2017. New research suggests that bigger, hotter wildfires are turning Canada’s vast boreal forest into a net source of climate-changing greenhouse gases. THE CANADIAN PRESS/Jonathan Hayward

Hotter, larger fires turning Canada’s boreal forest into carbon source: research

With climate change, fires are becoming more frequent, larger and more intense

Bigger, hotter wildfires are turning Canada’s vast boreal forest into a significant new source of climate-changing greenhouse gases, scientists say.

The shift, which may have already happened, could force firefighters to change how they battle northern blazes, said Merritt Turetsky, an ecologist at the University of Guelph and co-author of a paper that appeared in the science journal Nature on Wednesday.

“It’s making it much more difficult for us to target those reductions in human emissions because, all of a sudden, we have all these unaccounted-for sources.”

The boreal forest, a band of green that stretches over six provinces and two territories, has long been a storehouse of carbon.

Although fires sweep through as often as every 70 years, much carbon remains in the soil and slowly builds up — up to 75 kilograms of carbon per cubic metre, some of it thousands of years old.

But with climate change, fires are becoming more frequent, larger and more intense.

Researchers from five U.S. and four Canadian universities wanted to see if that was affecting stored carbon. They looked at the impact of the 2014 fire season in the Northwest Territories, which burned the largest area on record.

“These were large and severe fires,” said Xanthe Walker of Northern Arizona University. “We thought this is when and where (stored carbon) would burn.”

The team found that even after the fires, older forests continued to preserve carbon where it was protected by a thick layer of organic soil.

But the old carbon burned in nearly half of the younger stands where the soil wasn’t as thick. And what didn’t burn rapidly decomposed into the atmosphere.

“There are areas where there’s no organic soil left and it’s just exposed mineral soil,” Walker said.

Turetsky said the boreal forest is gradually becoming younger as fires increase in size and frequency.

“Now those old forests are young forests, so when the next forest fire hits that area, those are going to be systems that are vulnerable to legacy carbon release.

“We can have thousands of years of productivity stored and then released in a matter of minutes.”

At some point, fires will release more carbon from the boreal forest than it’s able to store.

“I think we’re right on the tipping point now,” Turetsky said. “I think it’s happening in the western provinces already. I think it’s happening in Alaska.”

This summer has been an unprecedented fire season across the circumpolar North. There have been more than 100 major fires burning north of the Arctic Circle and in boreal forests in places such as Siberia.

“That soil structure is all the same,” Walker said. “Presumably, they all have legacy carbon.”

The amount of old carbon released is still small, especially relative to that released by fossil fuels. But it complicates the task of bringing overall carbon emissions under control. It could also complicate how forest managers approach fires.

Wildfires in remote areas are often simply left to burn. Turetsky said firefighters may have to rethink that to protect stands that store a lot of carbon.

“The Canadian Forest Service is starting to think about old carbon as a valuable resource.”

The role of Canada’s huge forested areas is beginning to change, she said.

“Our forests are no longer carbon sinks.”

ALSO READ: Brazil’s president claims NGOs could be setting Amazon fires

Bob Weber, The Canadian Press


Like us on Facebook and follow us on Twitter.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Literacy Week coming to Trail: Make reading time, family time

Family Literacy Week in B.C. runs Jan. 26 to Feb. 2

The Voice of Raisin: A whiff down memory lane

The Trail Times is introducing a new column. Benjamin Howard recently moved… Continue reading

Rossland council okays temp shelter for local man

Garry Camozzi can stay in the trailer until October 2020

West Kootenay snowpack nearing record levels

High snowpack can mean a greater risk of flooding in spring, say forecasters

New York county gave Salmo River canyon its name

Place Names: Shenango Canyon, Sheep Creek City, Beaverville

‘Presumptive case’ of coronavirus in Canada confirmed by Ontario doctors

Man in his 50s felt ill on his return to Canada from Wuhan, China

People knowingly take fentanyl so make policy changes to reduce harm: B.C. study

Dr. Jane Buxton, an epidemiologist at the centre, says drug users need more resources,

‘My heart is going to bleed’: Bodies brought back to Canada following Iran plane crash

Remains of Sahar Haghjoo, 37, and her eight-year-old daughter, Elsa Jadidi, were identified last weekend

UBC grad and sister killed in Iran plane crash had bright futures ahead, close friend says

Asadi-Lari siblings Mohammad Hussein and Zeynab were two of 57 Canadians aboard downed Flight PS752

BCLC opens novelty bet on Harry and Meghan moving to the west coast

Meanwhile, real estate agency points to four possible homes for the family

Canada slips in global corruption ranking in aftermath of SNC-Lavalin scandal

The country obtained a score of 77, which places it at the top in the Americas

Wuhan bans cars, Hong Kong closes schools as coronavirus spreads

Hong Kong leader Carrie Lam said her government will raise its response level to emergency, highest one

B.C.’s oldest practising lawyer celebrates 100th birthday, shares advice

Firefighters bring Constance Isherwood a cake with 100 birthday candles

Most Read