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

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

Mackenzie Cox representing the first Black Shirt Day at North Island Secondary. (Zoe Ducklow Photo)
Port McNeill Grade 12 student observes Black Shirt Day for anti-racism

‘Wearing that colour T-shirt for that day is a commitment to show that we care.’

Port McNeill council file photo. (Tyson Whitney - North Island Gazette)
Port McNeill council approves utility fees increase

The fees cover the three major services the town provides; water, solid waste and sewage.

Black Press media file
RCMP catch alleged drunk driver

The driver provided breathalyzer samples in excess of 3.5 times the legal limit.

A scene from “Canada and the Gulf War: In their own words,” a video by The Memory Project, a program of Historica Canada, is shown in this undated illustration. THE CANADIAN PRESS/HO - Historica Canada
New video marks Canada’s contributions to first Gulf War on 30th anniversary

Veterans Affairs Canada says around 4,500 Canadian military personnel served during the war

A 17-year-old snowmobiler used his backcountry survival sense in preparation to spend the night on the mountain near 100 Mile House Saturday, Jan. 16, 2021 after getting lost. (South Cariboo Search and Rescue Facebook photo)
Teen praised for backcountry survival skills after getting lost in B.C.’s Cariboo mountains

“This young man did everything right after things went wrong.”

Conservative Leader Erin O’Toole holds a press conference on Parliament Hill, in Ottawa on December 10, 2020. THE CANADIAN PRESS/Sean Kilpatrick
No place for ‘far right’ in Conservative Party, Erin O’Toole says

O’Toole condemned the Capitol attack as ‘horrifying’ and sought to distance himself and the Tories from Trumpism

A passer by walks in High Park, in Toronto, Thursday, Jan. 14, 2021. This workweek will kick off with what’s fabled to be the most depressing day of the year, during one of the darkest eras in recent history. THE CANADIAN PRESS/Chris Young
‘Blue Monday’ getting you down? Exercise may be the cure, say experts

Many jurisdictions are tightening restrictions to curb soaring COVID-19 case counts

A health-care worker prepares a dose of the Pfizer-BioNTech COVID-19 vaccine at a UHN COVID-19 vaccine clinic in Toronto on Thursday, January 7, 2021. THE CANADIAN PRESS/Nathan Denette
COVID-19: Provinces work on revised plans as Pfizer-BioNTech shipments to slow down

Anita Anand said she understands and shares Canadians’ concerns about the drug company’s decision

Tourists take photographs outside the British Columbia Legislature in Victoria, B.C., on Friday August 26, 2011. A coalition of British Columbia tourism industry groups is urging the provincial government to not pursue plans to ban domestic travel to fight the spread of COVID-19. THE CANADIAN PRESS/Darryl Dyck
B.C. travel ban will harm struggling tourism sector, says industry coalition

B.C. government would have to show evidence a travel ban is necessary

(Phil McLachlan - Capital News)
‘Targeted’ shooting in Coquitlam leaves woman in hospital

The woman suffered non-life threatening injuries in what police believe to be a targeted shooting Saturday morning

Everett Bumstead (centre) and his crew share a picture from a tree planting location in Sayward on Vancouver Island from when they were filming for ‘One Million Trees’ last year. Photo courtesy, Everett Bumstead.
The tree-planting life on Vancouver Island featured in new documentary

Everett Bumstead brings forth the technicalities, psychology and politics of the tree planting industry in his movie

JaHyung Lee, “Canada’s oldest senior” at 110 years old, received his first dose of the COVID-19 vaccine on Thursday, Jan. 14, 2021. He lives at Amenida Seniors Community in Newton. (Submitted photo: Amenida Seniors Community)

Most Read