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

Wrangle the Chute returns to Kicking Horse

Wrangle the Chute will be returning to Kicking Horse Mountain Resort from… Continue reading

Kicking Horse Update Friday January 17

Kicking Horse reports 10 cm of snow in the last 24 hours,with… Continue reading

Highway Update Friday January 17

On Highway 1, watch for slippery sections between Three Valley Avalanche Gate… Continue reading

Golden nominated for Kraft Hockeyville 2020

Nominations close on Feb. 9.

Kicking Horse Update Thursday, January 16

Kicking Horse reports 3cm of snow in the last 24 hours,with snow… Continue reading

Kids across Canada more at risk of hospitalization from flu this season: doctor

Dr. Theresa Tam said influenza B does not usually peak until February or later

Closed mills, housing surge support a positive forecast for lumber industries

B.C. lumber producers have closed mills accounting for 18% of province’s capacity, RBC report says

Good Samaritan pays part of rent for B.C. woman facing eviction in can-collecting dispute

Zora Hlevnjak, 76, supplements her pension by collecting cans and receiving public donations

Kelowna’s ‘Baby Mary’ finds biological parents after more than 30 years

Geneologist and DNA test helped her connect with her biological parents

Kelowna hotel to award couples for baby-making with Nooner deal

The deal includes a free stay every Valentine’s Day for the next 18 years

On the job hunt with Nelson’s Make A Change Canada

The employment charity is organizing next week’s Kootenay Patricks, Montreal Canadiens game

‘Scariest boat ride of my life’: Passengers trapped by ice on rocky B.C. ferry sailing

The Nimpkish docked in Bella Coola on Jan.12 coated in a thick layer of ice

B.C. pair ordered to pay $55,000 for oil tank discovered four years after selling home

Judge says defendants breached contract, despite being unaware of tank until basement flooded

Canada to give $25,000 to families of each Canadian who died in Iran plane crash

Prime Minister Justin Trudeau also made it clear that Canada still expects Iran to compensate victims

Most Read