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Abstract Northern circumpolar permafrost thaw affects global carbon cycling, as large amounts of stored soil carbon becomes accessible to microbial breakdown under a warming climate. The magnitude of carbon release is linked to the extent of permafrost thaw, which is locally variable and controlled by soil thermodynamics. Soil thermodynamic properties, such as thermal diffusivity, govern the reactivity of the soil‐atmosphere thermal gradient, and are controlled by soil composition and drainage. In order to project permafrost thaw for an Alaskan tundra experimental site, we used seven years of site data to calibrate a soil thermodynamic model using a data assimilation technique. The model reproduced seasonal and interannual temperature dynamics for shallow (5–40 cm) and deep soil layers (2–4 m), and simulations of seasonal thaw depth closely matched observed data. The model was then used to project permafrost thaw at the site to the year 2100 using climate forcing data for three future climate scenarios (RCP 4.5, 6.0, and 8.5). Minimal permafrost thawing occurred until mean annual air temperatures rose above the freezing point, after which we measured over a 1 m increase in thaw depth for every 1 °C rise in mean annual air temperature. Under no projected warming scenario was permafrost remaining in the upper 3 m of soil by 2100. We demonstrated an effective data assimilation method that optimizes parameterization of a soil thermodynamic model. The sensitivity of local permafrost to climate warming illustrates the vulnerability of sub‐Arctic tundra ecosystems to significant and rapid soil thawing.
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Permafrost Food Storage Monitoring and Vulnerability Assessment in Utqiaġvik, Alaska
Traditional Iñupiaq sigḷuaq are cellars excavated into permafrost for storage of large quantities of game, fish, and other foodstuffs harvested for subsistence. Permafrost provides both a cultural and regulatory ecosystem service to Arctic peoples. A cellar thermal monitoring program in Utqiaġvik (formerly Barrow), Alaska, documented catastrophic flooding, collapses, and other issues in these cellars related to warming climatic conditions, community functions, and development. This paper provides an update on the Utqiaġvik monitoring program, which was operational from 2005 to 2019. All five monitored cellars exhibited stable to warming mean annual internal temperatures over the period of observation. Two cellars flooded, another was abandoned because of sloughing walls, and two were functioning until the COVID-19 pandemic. Based on experiences gained from the 14-year Utqiaġvik monitoring program, we conduct a vulnerability assessment using the source-pathway-receptor-consequence (SPRC) model and identify several vulnerability reduction measures. We recommend the SPRC model to aid evaluation of specific vulnerabilities of cellars and other traditional frozen infrastructure, and to improve future monitoring methods and products through increased community participation. Any attempt to provide data for community-resilience decisions should start with identifying and communicating process components, thereby bridging stakeholder learning and responses (their “heuristics” in the SPRC model) and science-based knowledge.
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- PAR ID:
- 10594203
- Publisher / Repository:
- ucalgary
- Date Published:
- Journal Name:
- ARCTIC
- Volume:
- 77
- Issue:
- 2
- ISSN:
- 0004-0843
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.14430/arctic79682
