permafrost
Sign in to savePermafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than . Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which free
AI overview
Permafrost is soil or underwater sediment that remains frozen year-round for at least two years, with some permafrost having stayed frozen for around 700,000 years. It matters because it covers vast Arctic regions and mountain areas, and changes to permafrost can affect landscapes, infrastructure, and ecosystems in these regions.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Soil.name
- Permafrost
- Soil.image
- Circum-Arctic Map of Permafrost and Ground Ice Conditions.png
- Soil.image_size
- 250px
- Soil.image_caption
- Extent and types of permafrost in the Northern Hemisphere as per International Permafrost Association
via Wikipedia infobox
Article
27 sectionsContents
- Classification and extent
- Continuity of coverage
- Discontinuous permafrost
- Continuous permafrost
- Alpine permafrost
- Subsea permafrost
- Past extent of permafrost
- Manifestations
- Base depth
- Massive ground ice
- Landforms
- Ecology
- Construction on permafrost
- Impacts of climate change
- Increasing active layer thickness
- Climate change feedback
- Impact on global temperatures
- Thaw-induced ground instability
- Infrastructure
- Release of toxic pollutants
- Revival of ancient organisms
- Microorganisms
- Plants
- History of scientific research
- References
- Sources
- External links
Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below a meter (3 ft), the deepest is greater than . Similarly, the area of individual permafrost zones may be limited to narrow mountain summits or extend across vast Arctic regions. The ground beneath glaciers and ice sheets is not usually defined as permafrost, so on land, permafrost is generally located beneath a so-called active layer of soil which freezes and thaws depending on the season.
Around 15% of the Northern Hemisphere or 11% of the global surface is underlain by permafrost, covering a total area of around . This includes large areas of Alaska, Canada, Greenland, and Siberia. It is also located in high mountain regions, with the Tibetan Plateau being a prominent example. Only a minority of permafrost exists in the Southern Hemisphere, where it is consigned to mountain slopes like in the Andes of Patagonia, the Southern Alps of New Zealand, or the highest mountains of Antarctica.