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Could peat moss save permafrost?

Peat has unique properties that scientists are evaluating as a way to help permafrost, but not when it's crushed, posing a challenge. photo sourced from Wikimedia Commons

Peat moss, found all over the NWT, could be key to saving infrastructure threatened by thawing permafrost.

Researchers at Canada's National Research Council are testing the properties of peat moss to make it into a building material that could be used to preserve permafrost under buildings and infrastructure.

"In research and investigation of peat lands, we've noticed that peat has a unique dual thermal conductive properties," said Igor Egorov, a research officer in civil engineering infrastructure for the NRC's Construction Research Centre.

"We're thinking, can we use these unique properties for application in the construction industry?"

Peat is porous, so it contains air in the summer and ice in the winter in the NWT, each working in their season to cool the ground. During summer, the unfrozen peat has very low thermal conductivity – it is basically an insulator, protecting the permafrost layer from heat. In the winter, the frozen peat becomes conductive. It contains ice and draws warmth from the soil to the atmosphere.

A problem off the bat is that the peat used in construction can't be crushed or flattened – it must remain porous. Egorov's team is looking at ways to reinforce its structure, as well as methodologies for measuring the properties of peat.

"We're trying to find the optimal properties for our product," he said.

By 2050, 15 to 20 per cent of near-surface permafrost may be thawed or degraded, according to Egorov. At the same time, Canada has close to 100 million hectares of peat land.

"We have to understand how this peat works and why permafrost is associated with peat and maybe we will be able to mimic these properties to preserve our Northern communities from degradation processes."

Regions of the northwestern NWT, in particular, have seen increased thermokarsts and thaw slumping – sinkholes and landslides caused by permafrost thaw, respectively – in recent years.

Research led by NWT Geological Survey geologist Dr. Steve Kokelj has found the patterns of this phenomenon correspond with the area that was once, in prehistory, covered by the Laurentide Ice Sheet. This may help predict where this phenomenon is more likely to happen.

Egorov said the NRC's peat moss system would ideally be part of a larger mix of systems called "inter-seasonal cold redistribution."

"It means we're capturing extra cold during the winter and we're storing this extra cold in the soil, in the form of ground ice, and redistribute the cold in the summer. In this way we can protect and preserve the permafrost."

Some methods, such as the peat moss, would be passive – requiring no energy – while others would run off renewable energy sources.

Egorov's team is working a powered permafrost-freezing method that works on renewable energy that has already seen some success in testing in the NWT. He says it would prove very competitive with thermosyphons, the most common stabilization technology in use in the North, as it is more efficient and effective during mild seasons.

"We've managed not only stabilize permafrost but refreeze it where it's already degraded."

Egorov said his team will soon reach out to Northern governments to pitch partnerships.