How Permafrost Thaw Threatens Canada’s North

How Permafrost Thaw Threatens Canada's North

Climate Change and The North

Permafrost thaw is one of the many issues northern communities are facing due to climate change. Scientists have determined temperatures in the Arctic are increasing at a rate almost double that of the global average.

This has led to melting sea ice, coastal erosion, impacts to wildlife, and intensified wildfires. These fluxes are forcing a population of mostly Indigenous peoples, to adapt constantly – and with minimal resources to do so.

Canadian researchers have long known the importance of monitoring Arctic conditions for understanding climate change. However, more focus is now being placed on the wellbeing of its residents and local implications.

Permafrost thaw causing an altered landscape and the release of carbon and mercury among other environmental elements.
Permafrost thaw causing an altered landscape and the release of carbon and mercury among other environmental elements. [Image: A. Balser/CarbonBrief]

The Issue with Permafrost Thaw

I had the pleasure of speaking with a researcher from Wilfrid Laurier University about permafrost thaw and how it connects to human health. Kristen Bill, a PhD student, has devoted years of study to understanding the effects of fire disturbance in cold climates. Currently she is analyzing changes in environmental elements as a result of melting permafrost.

Permafrost is soil that remains frozen for at least two years. It is a main component of Arctic ecosystems and contains massive amounts of carbon, about twice the amount currently found in Earth’s atmosphere. It also contains stores of other elements including mercury, phosphorus and nitrogen. As abrupt wildfires and long-term global warming heat up the landscape, this releases frozen deposits and alters the landscape irreversibly.

If the extent of permafrost melt reaches a tipping point, thermokarst bogs and lakes are formed which leads to further greenhouse gas emissions. But for local communities, certain pollutants are a more acute concern.

Mercury from permafrost thaw becomes toxic methylmercury which bioaccumulates through Arctic food webs exposing Indigenous hunters.
In aquatic ecosystems, mercury from permafrost thaw becomes toxic methylmercury. Methylmercury (MeHg) bioaccumulates through Arctic food webs exposing Indigenous hunters. [Image: Lehnherr, 2014]

Mercury Exposure in Traditional Diets

Mercury, more specifically methylmercury (MeHg), is an organic toxin that can cause neurological symptoms and cardiovascular disease. It is particularly toxic to developing fetuses. Researchers like Kristen are currently working on connecting the dots between permafrost thaw and MeHg exposure to humans.

Microbes in aquatic systems naturally produce MeHg by metabolizing elemental mercury. Once it enters the food web, it bioaccumulates and becomes concentrated in top predatory fish, seals and whales. Since Indigenous communities rely heavily on their environment for sustenance, a main part of their diet puts them at higher risk of MeHg poisoning.

Northern ecosystems are at a precipice of change and we need to make sure communities have the knowledge to cope.”

Kristen Bill, WLU PhD Student

Signs of Alarm

In 2011, the AMAP (Arctic Monitoring & Assessment Programme) released a report on Mercury in the Arctic. They highlighted arctic char, ringed seals, and beluga whales as having levels above the guidelines for safe consumption.

The AMAP and others have reported toxic levels of MeHg found in blood, hair and umbilical cord samples of communities consuming these meats. One study found 78% of childbearing-age women had at-risk blood levels.

Researcher Kristen Bill collecting soil water samples in a peatland area near Norman Well, NWT.
Researcher Kristen Bill collecting soil water samples in a peatland area near Norman Well, NWT [07/2021].

Connecting to Permafrost Thaw

It’s difficult for scientists to definitively link the MeHg from permafrost thaw to community exposure. In order to understand the full picture, scientists must try to map out the pathway between the two. This includes its transformation from mercury to MeHg, travel to local hunting areas, accumulation through the food chain and presence in human samples.

There are other sources of environmental mercury that further complicate these efforts. Deposition of atmospheric mercury from anthropogenic sources continues to pollute the Arctic. External factors including precipitation, microbial numbers and changes in seasonal ice all influence MeHg in the environment.

permafrost thaw and climate change create unknown futures for Inuit people.
An Inuit child faces an unknown future in the face of climate change.
[Image: RyersonClark/CanvaPro]

The Arctic Needs Your Attention

Although many of us feel far removed from Canada’s north, our actions can influence their story. Research like Kristen’s helps to inform policy decisions and leads to practical solutions for communities. Public knowledge and awareness of these issues can make Indigenous health and permafrost thaw a priority for the Canadian government.

Some ways you can help:


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