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Arctic infrastructure at risk due to permafrost degradation

Written by  TheCivilEngineer.org

According to a new study, the infrastructure in Alaska and in multiple regions in the Arctic is threatened by the quick degradation of permafrost.

A block of thawing permafrost that fell into the ocean on Alaska’s Arctic Coast. A block of thawing permafrost that fell into the ocean on Alaska’s Arctic Coast. U.S. Geological Survey
02
August

Permafrost refers to any type of soil or rock formation that remains frozen (its temperature is under 0°C) for at least 2 years. It is widely found in Siberia, Canada, Greenland, and Alaska (85 % of Alaska lies upon a layer of permafrost). The deterioration of the infrastructure in the Arctic will be faster than anticipated since the previous studies did not account for the impact of the structure on permafrost. It is estimated that about 35 million people live in the permafrost zone. 

Scientists have consistently studied the impact of thawing on permafrost since it significantly affects its stiffness and its strength. Thus, permafrost degradation may lead to the ground's subsidence and cause structural failures. Recent studies reveal that the Arctic is warming at around twice the rate as the rest of the world, with permafrost already starting to thaw across large areas.

The authors of the study emphasize that permafrost is not only affected by climate change but also by the infrastructure constructed on top of it. For example, snow clearance at the road surface leads to strong subsurface winter cooling while an embankment creates insulation. The study suggests that the current prediction models to derive the permafrost changes have been significantly improved over the past years however the impact of infrastructure has not been accounted for. The concept of 1D thawing (top-down) is convenient but rather simple and cannot take into consideration important factors that accelerate permafrost thawing (e.g., soil erosion, groundwater table, snow redistribution, etc.).

Scientists focused on a gravel road constructed on continuous permafrost. They conducted computer simulations to deduce that gradual thawing leads to irreversible permafrost decay and subsequently, to road failure. In fact, the failure came earlier than previous research suggests. Simple top-down thawing was found to be inadequate to describe the permafrost degradation since lateral destabilization of the road’s embankment was detected. The findings are applicable to all types of infrastructure in the Arctic including roadways, bridges, pipelines and buildings.

The results indicate that it is critical to account for the climate change effects and the impact of infrastructure on permafrost which can transform from a stable to an unstable formation rapidly. In fact, the degradation of Permafrost could readily occur within the lifetime of a project (around 30 years) and cause severe ramifications.

Permafrost decay in Canada is currently causing financial losses of millions of $ annually. In Alaska, the total economic damage caused by permafrost conditions and other climate-related factors is estimated at $5.5 billion

Sources: Leeds.ac.uk NRDC UniversityofAlask Fairbanks Von Deimling et al. (2021)

 

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Thawing permafrost in Alaska presents threats CBS
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