Where is permafrost?

The vast, diverse northern permafrost zone spans from the Canadian High Arctic to sub-Arctic Alaska and boreal Canada, to mountains in the lower 48 U.S. States, much of Russia, some of Europe, and even atop Mauna Kea in Hawaii.

Permafrost is a crucial part of the ecosystems of the Arctic tundra and large swaths of boreal forest in Alaska, Siberia, Canada, and Greenland. It underlies 15% of land area in the Northern Hemisphere.^[1] Permafrost can be found beneath the Arctic Ocean, the Arctic tundra, alpine forests, and boreal forests.

In many places, forests, plants, and peat act as protective insulation for northern permafrost. This insulation helps keep carbon-storing organic matter, like plants and animals, as well as bacteria and archaea, frozen in the permafrost.

Below are some examples of permafrost-reliant ecosystems:

Forests

Photo by: Brendan Rogers

In the boreal forests of Russia and North America, also known as the taiga, permafrost prevents water from draining off the landscape, sustaining the trees that shade the soil and keep the permafrost cool. In these forests, permafrost tends to develop in some areas and not in others, establishing a patchy pattern.^[2]

Peatlands

Photo by: © Chris Linder

Peatlands are waterlogged terrestrial ecosystems that can form in wet and cold regions where decomposition, or the breakdown of organic matter, happens slowly. This allows partially decayed plant material, known as peat, to build up over time.^[2]

As peatlands grow over permafrost, older peat has the potential to freeze and merge with the permafrost column. On the surface, however, moss and lichen continue to grow, die, and decompose, forming new peat. Moss insulates the ground, protecting it from temperature changes while also providing protection for the underlying permafrost and staving off thaw.^[2]

Tundra

Photo by: © Chris Linder

Tundra is frozen ground in northern regions, appearing northward of where forests can grow, as well as in higher elevation and colder regions. The majority of the earth is frozen for most of the year, but during the short summer, small wildflowers, shrubs, mosses, and lichen make the most of the shallow layer of soil that thaws.^[2]

References

¹Obu, J. (2021). How Much of the Earth’s Surface is Underlain by Permafrost?. Journal Of Geophysical Research: Earth Surface, 126(5). doi: 10.1029/2021jf006123

²Unstable Ground. 2021. The Frozen Ground of the Far North is Thawing.. [online] Available at: https://unstableground-whrc.hub.arcgis.com/apps/woodwell::the-frozen-ground-of-the-far-north-is-thawing-/explore [Accessed 29 August 2022].