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.

Just Posted

Co-accused in Penticton home invasion, standoff granted bail again

Jesse Mason was granted bail this morning, co-accused Josef Pavlik’s bail was denied

Summerland Fire Department organizes gift drive

Toys and Toonies for Tots and Teens campaign begins at Festival of Lights on Nov. 29

Penticton artist brings joy to others through her painting

Hedy Munawych is 96 years old and just loves painting the beauty of the world around her.

Farm-to-kitchen Italian style pizzeria opens on Penticton’s Westminster Street

Pizzeria Tratto is set up so diners can see their food being made

Okanagan teenagers found after missing for four days

The pair, believed to be dating, had been missing since Nov. 15.

Bye bye Bei Bei: Giant panda born in U.S. zoo heads to China

Panda heads back to China as part of cooperative breeding program

B.C.’s ‘Dr. Frankenstein of guns’ back in jail yet again for trafficking in Glock parts

Bradley Michael Friesen has parole revoked for allegedly importing gun parts yet again

B.C. woman suing after laser hair removal leaves her with ‘severe’ burns, scarring

Nadeau felt ‘far more pain’ than usual during the treatment

Gift of science spread to low-income Okanagan families

Okanagan Science Centre matching donations until Dec. 1

$2.9 million judgment in B.C. blueberry farm sabotage lawsuit

The new owners saw most of their farm ruined just as they took possession

B.C. to more than double sales tax on vaping products

Tax up from 7 to 20 per cent, tobacco tax up two cents

Agreement signed for new Osoyoos Museum facility

The Osoyoos Museum Society lease takes effect Jan. 1, 2020

Spike belt stops stolen truck in Armstrong

Police dog used in search for suspect, one arrested

Most Read