Understanding the melting of permafrost to adapt to it

This text is part of the special Research section: climate issues

“Northern Canada has warmed and will continue to warm at a rate more than twice the global rate,” we learned in 2019 in a scientific report from Environment Canada. We can also expect “large areas” of permafrost to have melted by 2050.

In the north of the country, we no longer wonder if climate change is real: its effects are visible every day, on infrastructure and landscapes. “Above all, we wonder how we will adapt,” explains Pascale Roy-Léveillée, professor in the Department of Geography at Laval University. The researcher has made it her mission to document this new reality to allow those who will experience it to better prepare for the future.

Upset landscape

Permafrost, which covers nearly half of Canada’s surface, contains large quantities of methane, a powerful greenhouse gas, which will be released into the atmosphere as it thaws. It also supports infrastructure in the North, whether buildings or transport routes, such as roads and railways. “At the turn of the 20the century, when we built the railways, we believed that the permafrost was as solid as rock,” recalls Pascale Roy-Léveillée.

Not quite anymore. Already, the melting of this frozen ground is leading to the subsidence of certain surfaces and disrupting the landscapes. The tundra, usually covered with moss and lichen, is slowly being covered with trees and shrubs, emboldened by the thawing of the ground which allows them to sink deep roots. “People get stuck in it,” notes the researcher. This new vegetation also becomes an obstacle for snowmobile travel.

Beyond the vegetation, the entire landscape is changing, sometimes abruptly. A concrete example: lakes. “We can see that the lakes are growing, which is a completely normal phenomenon, but which is accelerated today,” says the woman who also holds the Partnership Research Chair on Permafrost in Nunavik, whose activities are part of the Sentinel North program. “Once too full, the lake will catch a river or a drop and suddenly empty, in less than 48 or 72 hours. » Result: locals accustomed to fishing in the body of water will arrive, their rod in hand, to find a dried-up depression.

For a population that relies on hunting, fishing and gathering for the vast majority of its diet, such a change can be disastrous.

Unstable infrastructure

Local infrastructure is also suffering from the sudden malleability of permafrost. To prevent disasters, Pascale Roy-Léveillée and her colleagues went to measure the soil on which buildings in Nunavik communities rest. Are they made of ice or rock? The next step will be to decide what to do with the buildings most at risk. “In Nunavut, we are planning construction on piles,” indicates the researcher, who estimates that this type of installation will multiply north of 55e parallel.

Critical transportation routes, such as the Hudson Bay Railway, which connects northern and southern Manitoba, are also threatened by unstable soil. Pascale Roy-Léveillée is participating in a project, in collaboration with geomorphologists, geocryologists and engineers, which will document the permafrost along the rails and draw up a portrait of current and future risks.

Support adaptation

“We, in the South, often wonder what the effects of warming are on infrastructure in the North, because we are an urban population who live in a very built-up environment,” notes Pascale Roy-Léveillée. But in the North, the proportion of the built landscape is very low. »

Well aware of her biases, the researcher prefers to ask Northern communities what their needs are to decide on her next study subjects, rather than trusting her instinct. What are their concerns, their questions? “We cannot adapt to a risk that we do not understand well,” she summarizes. Depending on the requests, it will document mercury levels in the soils of the Old Crow Plain, known locally as Van Tat, in Yukon, or the risk of landslides in Salluit, in Nunavik.

“Sometimes the news is better than expected,” rejoices the professor. It’s important to give good news when there is any. This helps reduce the anxiety of people in the North who are facing these changes on their territory. Because their territory is them. »

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