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Types of permafrost
Thawing permafrost can affect the land in different ways depending on the type of permafrost. Ground surface collapse or thaw subsidence can occur as long as ground ice is present. This graphic illustrates the range of scenarios of interactions between permafrost and agriculture.
Type 1 is ice-poor permafrost — ground with thaw-stable permafrost that will not experience subsidence.
Type 2 has ice lenses, which are horizontal, lens-shaped layers of ice near the surface. Ice lenses are thaw- unstable and their melting will cause some subsidence.
Types 3 and 4 are ice-rich permafrost consisting of interconnected wedge-shaped masses of ice called ice wedges. Permafrost containing ice wedges is considered thaw-unstable, and can cause significant subsidence. Types 3 and 4 are most likely to pose challenges in agricultural fields.
Type 1 is ice-poor permafrost — ground with thaw-stable permafrost that will not experience subsidence.
Type 2 has ice lenses, which are horizontal, lens-shaped layers of ice near the surface. Ice lenses are thaw- unstable and their melting will cause some subsidence.
Types 3 and 4 are ice-rich permafrost consisting of interconnected wedge-shaped masses of ice called ice wedges. Permafrost containing ice wedges is considered thaw-unstable, and can cause significant subsidence. Types 3 and 4 are most likely to pose challenges in agricultural fields.
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Look for this icon as you walk to learn more about ice wedges!
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A modified version of the above figure was published in:
Ward Jones, M. K., Schwoerer, T., Gannon, G., Jones, B. M., Kanevskiy, M. Z., Sutton, I., St. Pierre, B., St. Pierre, C., Russell, J., and Russell, D. (2022). Climate-driven expansion of northern agriculture must consider permafrost. Nature Climate Change, 12, 699-703. https://doi.org/10.1038/s41558-022-01436-z.
Ward Jones, M. K., Schwoerer, T., Gannon, G., Jones, B. M., Kanevskiy, M. Z., Sutton, I., St. Pierre, B., St. Pierre, C., Russell, J., and Russell, D. (2022). Climate-driven expansion of northern agriculture must consider permafrost. Nature Climate Change, 12, 699-703. https://doi.org/10.1038/s41558-022-01436-z.
Art and research by Mikhail (Misha) Kanevskiy, assistant research professor at the Institute of Northern Engineering and coinvestigator of the Permafrost Grown Project.
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