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

RCMP target Surrey school zones

Police and community partners launch ‘Think of Me’ campaign

Here’s why you may not have seen many federal election signs in Surrey

Earlier this year, Surrey council banned election signs on public property, highways

‘Men of Curling’ calendar features Surrey’s Tardi, who went rock climbing with a curling rock

Tyler Tardi, 21, now curls on men’s circuit, meaning he won’t play at 2020 nationals in Langley

Police, volunteers to deliver South Surrey students’ road-safety messages

Elementary designs aim to remind drivers to slow down, pay attention on the road

‘Jail’ time for Surrey business and community leaders in Crime Stoppers fundraiser

Metro Vancouver organization to host Jail & Bail event Friday at Central City’s outdoor plaza

Charges dropped against officer who shot and killed Hudson Brooks in South Surrey

‘I feel like I’ve lost Hudson all over again,’ says mom

‘This is not a drill’: Whistler Blackcomb gets first snowfall of the season

The 7th Heaven Summit had a dusting of snow Tuesday morning

Legislature gifts, clothing, travel need better control, B.C. auditor says

Audit follows suspensions of top managers by Speaker Darryl Plecas

Photos surface of Conservative candidate at B.C. event with people in blackface

The controversial “Black Peter” character has been a feature at Sinterklaas celebrations

Abbotsford restaurant offering free meals for those unable to pay

Veerji Fish ‘n’ Grill on Clearbrook Road has been giving away food since the summer

Arrest made after fourth threat closes a Kamloops high school in nine days

Mounties have been chasing down a series of threats made to schools across Kamloops

Nelson man accused of swimming naked at Toronto aquarium expected to plead guilty

David Weaver, of Nelson, was arrested and charged in October of last year

VIDEO: Party leaders react to Trudeau’s brownface photo bombshell

Fallout from Justin Trudeau’s brownface photo, and two other instances, sure to dominate campaign

Most Read

l -->