A so far underestimated environmental risk lurks in the frozen ground of the Arctic. Around 25 percent 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? Foundations can crack and tilt, and pipes rupture, even at an early stage. A research team has been investigating the risk of pollution where industrial facilities and infrastructure are sitting on thawing permafrost.
One member of this team is Sebastian Westermann, Associate Professor at the Department of Geosciences, University of Oslo, who for several years has conducted research on the cryosphere: the frozen part of the Earth's surface. 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 coming along with thawing permafrost. Their findings give cause for serious concern.
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 and first author of the study, 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, explains Langer. 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 environmental 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 can be toxic diesel to heavy metals and even radioactive waste. As climate change procedes, the "sleeping giant" may become an acute threat.
– Areas with permafrost are warming between twice 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, says Sebastian Westermann. But there is no systematic monitoring of permafrost conditions around polluting sites. When the permafrost thaws, it no longer provides an effective barrier and pollution over several decades can be released and spread over larger areas, he elaborates.
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 tons 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 the 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 percent of the global permafrost is located. Data from Canada and Alaska showed that by using information about the location and type of facility from there, 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 best documented environmental pollutants.
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 for 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.
Calls for a strategy for the Arctic and a monitoring system for dangerous substances
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. This at a time when it is becoming more and more difficult to remove such environmental hazards - after all, it often requires vehicles and heavy equipment, which can hardly be used on vulnerable tundra soil that is no longer stable due to thawing permafrost.
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The research team is calling for more data, and a monitoring system for dangerous substances in connection with industrial activity in the Arctic. Other important tasks they highlight are intensified efforts to prevent the release of environmental toxins and 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 shield against the risks of storing environmental toxins.
More about research on permafrost at titan.uio.no:
- Permafrost in the Arctic can thaw faster than presumed
- Arctic infrastructure under risk from permafrost thaw, scientists warn
Reference to the scientific article
Langer, M., von Deimling, T.S., Westermann, S. et al. Thawing permafrost poses environmental threat to thousands of sites with legacy industrial contamination. Nat Commun 14, 1721 (2023). https://doi.org/10.1038/s41467-023-37276-4