An example of infrastructure that is founded on soil with permafrost. A pipeline system for transporting oil through the Alaskan wilderness.

Environmental time bombs: The risks of thawing permafrost in the Arctic

Permafrost thaws and can result in unstable ground conditions. This can lead to collapsing industrial plants and environmental toxins leaking into vulnerable nature.

A previously underestimated environmental risk lurks in the frozen ground of the Arctic. 

Around 25 per cent of the land in the Northern Hemisphere has permafrost to a depth of up to hundreds of metres into the ground all year round. This continuously frozen state is called permafrost. Permafrost is found in many places in the Northern Hemisphere: Alaska, northern parts of Canada, Siberia, and in Greenland and Svalbard to name the main regions.

Permafrost has been seen as providing safe and stable ground to build on, but what happens when the surface permafrost thaws? A research team has been investigating the risk of pollution where industrial facilities and infrastructure have been built on thawing permafrost.

Sebastian Westermann, an associate professor at the Department of Geosciences, University of Oslo, has been conducting research on the cryosphere - the frozen part of the Earth's surface - for a long time.

Together with research colleagues from Germany and the Netherlands, he currently has an article in Nature Communications about industrial plants in the Arctic and problems associated with thawing permafrost. 

Their findings give cause for serious concern.

Sebastian Westermann has long collaborated with colleagues from the Alfred Wegener Institute on research on the permafrost in the Arctic. In their article, they warn against the industrial legacy of pollution that lies in the frozen ground.

Assumed that permafrost provided stable and leak-proof ground conditions

Many people imagine that the Arctic mostly consists of untouched and uninhabited wilderness, but in reality there are many interventions such as oil fields and pipelines, mines and various other industrial activities. 

Many facilities are built on permafrost, which was assumed to be safe ground. But this was before the climate became warmer.

The permafrost was not only considered as a solid platform for buildings and infrastructure. 

“Traditionally, it's also been considered a natural barrier that prevents the spread of pollutants,” says leader of the research group, Moritz Langer from the Alfred Wegener Institute (AWI)  in Germany. “Consequently, industrial waste from defunct or active facilities was often simply left on-site, instead of investing the considerable effort and expense needed to remove it.. 

As a result of industrial expansion during the Cold War, this led over the decades to micro-landfills full of toxic sludge from oil and gas exploration, stockpiles of mining waste, abandoned military installations ,and lakes where pollutants were deliberately dumped.

According to the research team, there are at least 13,000 to 20,000 contaminated areas in the Arctic, which could pose a serious risk of environmental pollution in the future.

Industrial ‘legacy’ in the form of unsecured toxins

At the plants, it was believed that the permafrost sealed toxins from production, and that there was no need for expensive disposal storage. Today, this industrial heritage is still buried in the permafrost or lying on the surface.

It could be toxic diesel, heavy metals, or even radioactive waste. As climate change procedes, the ‘sleeping giant’ may become an acute threat.

“Areas with permafrost are warming between two and four times as fast as the rest of the world. We know that in many places, permafrost is already in the process of thawing and disappearing altoghether,” Sebastian Westermann says. 

However, there is no systematic monitoring of permafrost conditions around polluting sites, he adds. When the permafrost thaws, it no longer provides an effective barrier and pollution over several decades can be released and spread over larger areas.

And when the ground collapses under plants or infrastructure, it can damage pipelines, chemical stores, and depots. This happened in 2020 near the industrial city of Norilsk in Northern Siberia. A destabilised storage tank released 17,000 tonnes of diesel, polluting the surrounding rivers, lakes, and the tundra.

Mapping of industry and infrastructure

At the start of the study, the researchers had to map and obtain data on industry in the Arctic. They found the data in OpenStreetMap and Atlas of Population, Society and Economy in the Arctic, which showed that about 4,500 industrial areas either store or use potentially hazardous substances in permafrost areas in the Arctic. The sources did not contain data on the type of facility, or how badly they could potentially pollute the environment.

Detailed information on contaminated areas was only available for North America, where about 40 per cent of the global permafrost is located. 

Data from Canada and Alaska showed that by using information about the location and type of facility from these areas, they could accurately estimate where hazardous substances were most likely to be found in the Arctic.

For Alaska, they also gained insight into the type of contamination in the Contaminated Land Programme. About half of the pollution is attributed to fuels such as diesel, kerosene, and petrol. 

Mercury, lead, and arsenic are also among the 20 most documented environmental pollutants.

A mining facility located in an area with permafrost: The Red Dog Zink Mine in northwest Alaska. This is the world's largest producer of the mineral zinc, and lead is also extracted.

For Siberia, they found no comparable data for the industry. The only opportunity was to analyse reports on environmental problems in the Russian media and freely available sources between 2000 and 2020. But the somewhat sparse information they found indicates that industrial plants and polluted areas are also to be found in Russia's permafrost regions.

Using computer models, the team was able to calculate the occurrence of contaminated areas in the Arctic. According to the results, the researchers found that the 4,500 industrial plants in regions with permafrost most likely produced between 13,000 and 20,000 contaminated areas. 

Between 3,500 and 5,200 of the contaminated areas are in regions where the permafrost is still stable but will begin to thaw before the end of the century.

A monitoring system for dangerous substances is needed

The interest in conducting commercial activities in the Arctic is increasing, and this could mean more industrial facilities. 

Plants that can release toxins into nearby ecosystems, at a time when it is becoming more and more difficult to remove such environmental hazards. After all, this often requires vehicles and heavy equipment that can hardly be used on vulnerable tundra soil that is no longer stable due to thawing permafrost.

The research team is calling for more data and a monitoring system for hazardous substances related to industrial activity in the Arctic. They also highlight the need for intensified efforts to prevent the release of environmental toxins and to undo the damage in the areas that are already polluted. 

They no longer consider it appropriate to leave industrial waste in the Arctic without safe disposal options. Permafrost can no longer be relied upon to mitigate the risks associated with storing environmental toxins. 


Moritz Langer Thawing permafrost poses environmental threat to thousands of sites with legacy industrial contaminationNature Communications, 2023. 


Read the Norwegian version of this article at

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