Wildfires can triple permafrost thaw in N.W.T., Alberta for up to 30 years, says study

As wildfires are growing larger across the North a new study suggests they're causing permafrost to thaw faster.

The study by the University of Alberta was published in Nature Communications this month and found that, over the past 30 years, wildfires have caused nearly a quarter of all permafrost thawabout 2,000 square kilometres of peatlands in Alberta and the Northwest Territories.

Wildfireswere also found to triple the rate of abrupt permafrost thaw in Western Canada's boreal peatland region up to 30 years after a fire.

"When we started we really had no idea of the scale or the magnitude of it so we were absolutely surprised at just how big that number was," said lead researcher Carolyn Gibson.

At the time, she was a master's student at the University of Alberta. Now she ispursuing her PhD at the University of Guelph. She's studying how permafrost affects ecosystems and community well-being.

Gibson explained that permafrost has always undergone a natural cycle of thawing and reforming, but abrupt permafrost thaw is considered irreversible.

"Our climate's just getting too warm to help support that," she said. "It most likely won't come back and those ecosystems are now sort of indefinitely changed."

• VIDEO |Giant craters in Canada's melting permafrost impacting climate change: researchers

The researchers examined a series of sites from northern Alberta up to Fort Simpson, N.W.T. and beyond using remote sensing techniques to look at permafrost thaw over large areas. They also looked at fires in the region from the1970sto 2014.

Theyfound that wildfires have a cumulative effect which carries over from year to year. While forests may regenerate after a fire,there is still accelerated thawing occurring in the ground below, Gibson said.

Global and local impacts

Thawing permafrost has many impacts both locally and globally, Gibson said, affecting infrastructure, land use and water resources.

"As permafrost thaw occurs that's when we start to see the heaving of highways and roads and cracks in the buildings," she said.

Once permafrost thaws, the land becomes boggy, which can be challenging to walk or drive an all-terrain vehiclethrough, she added. And researcherspredict thawing will cause the loss ofwoodland caribou habitat.

Gibsonalso said permafrost acts as a warehouse for stored carbon, which, once thawed, releases carboninto the atmosphereas carbon dioxide or into water as dissolved carbon.

"That just further enhancesthis climate warming cycle and so that's felt globally," she said. "Even though it's occurring in the North, things that happen in the North don't stay in the North, that has global impacts all around the Earth."

It's not all 'doom and gloom'

While there's not much people in the North can do to prevent the permafrost from thawing, Gibson said there is some good news.

Researchers are working to better predictthawing patterns to help inform mitigation and adaptation efforts like wildlife management and public policy decisions.

"We can be much more proactive in our decisions. So where should we be building infrastructure? Do we need to start thinking about adaptation strategies?" said Gibson.

"So it sounds all doom and gloom, but it's not."

With files from Loren McGinnis and Katie Toth