Permafrost Thaw in Alaska
Evidence suggests that permafrost temperatures in Alaska have risen by 2°C in the last 30 years affecting local communities
What is permafrost?
Permafrost is defined as ground, composed of rock, soil, or sediment, with a temperature that remains at or below freezing (32° F or 0° C) for two or more consecutive years (Alaska DGGS).
It can extend down beneath the earth’s surface from a few feet to more than a mile, cover entire regions, or even an isolated spot (Denchak, 2018).
About a quarter of the entire northern hemisphere is permafrost where the ground is frozen year round (Denchak, 2018).
In Alaska, permafrost is found beneath nearly 85 percent of the state (Alaska DGGS).
It is thickest and most extensive in arctic Alaska north of the Brooks Range, and extends as much as 2,000 feet below the surface of the Arctic Coastal Plain. Southward from the Brooks Range it becomes increasingly thinner and more discontinuous. In Southeast Alaska is is virtually absent (Alaska DGGS).
Why is it important?
This below freezing ground provides a stable foundation for structures and infrastructure in cold-climate regions (Alaska DGGS).
Thawing of permafrost releases greenhouse gas emissions, causes landslides, ground subsidence, erosion, lake disappearances, new lake development, and saltwater encroachment into aquifers and surface waters (Alaska DGGS).
Climate change has contributed to the thawing of permafrost and as thawing continues it can disrupt the communities who live on the land.
How permafrost thaw is affecting the city of Nome?
The city of Nome is located on the southern coast of the Seward Peninsula.
Nome, Alaska
The climate of Nome is characterized as subarctic with short, cool summers and long, cold winters (Birchall & Bonnet 2019).
The city of Nome has a population of approximately 3600 residents (Kettle, et al., 2017).
Nome serves as a regional and economic hub for 16 tribal villages in the region, supporting industrial and commercial needs (Kettle, et al., 2017).
Implications of permafrost thaw in Nome
The permafrost layer beneath the community is relatively thin, at approximately 15–50 m, and is thus increasingly susceptible to warming temperatures (Birchall & Bonnet 2019).
Evidence suggests that permafrost temperatures in Alaska have risen by 2°C in the last 30 years (Birchall & Bonnet 2019).
In Nome, thawing permafrost has influenced infrastructure in three critical ways: building subsidence, utilities failure and road undulation (Birchall & Bonnet 2019).
Policy tools and mitigation efforts
Expanding access to funding for infrastructure and maintenance will be vital in protecting buildings, roads, and other infrastructure from the effects of permafrost thaw in Alaska.
By 2030, permafrost degradation is expected to raise the costs of maintaining public infrastructure by U.S. $3.6 billion to $6.1 billion (Union of Concerned Scientists, 2011).
Having adequate funding available to invest in technologies like thermosyphon can help keep permafrost frozen, thus preventing further subsidence, utilities failure, and road undulation in the city of Nome.
This technology is being used in places like Alaska and Canada.
This technology is being used in the support beams of the Trans-Alaska pipeline.
While these technologies may not completely stop the problem, it is a proactive measure aimed to help mitigate some of the impacts induced by permafrost thaw.
References
Birchall, S.J. & Bonnett, N. (2019). Thinning sea ice and thawing permafrost: climate change adaptation planning in Nome, Alaska. Environmental Hazards, 19(2), 152–170. https://doi.org/10.1080/17477891.2019.1637331
Carlton, J. (2009, December 7). Keeping it frozen. The Wall Street Journal. Retrieved from https://www.wsj.com/articles/SB10001424052748704576204574531373037560240
Daanen, R. (n.d.). Permafrost and Periglacial Hazards. Alaska Division of Geological & Geophysical Surveys (DGGS). https://dggs.alaska.gov/hazards/permafrost.html.
Denchak, M. (2018, June 26). Permafrost: Everything You Need to Know. NRDC. https://www.nrdc.org/stories/permafrost-everything-you-need-know
Kettle, N., Martin, J., & Sloan, M. (2017). Nome Tribal Climate Adaptation Plan. Nome Eskimo Community and The Alaska Center for Climate Assessment and Policy. Fairbanks, AK.
Permafrost. (2011). In National Geographic. Retrieved from https://www.nationalgeographic.org/encyclopedia/permafrost/#:~:text=Continuous%20permafrost%20extends%20under%20all,thick%20vegetation%2C%20stays%20all%20year.
Union of Concerned Scientists. (2011). Climate Hot Map Nome Alaska. Retrieved from: https://www.climatehotmap.org/global-warming-locations/nome-ak-usa.html#:~:text=The %20region%20is%20home%20to,rest%20of%20the%20United%20States
