Related topics: carbon dioxide · climate change

Climate change is threatening unique permafrost landforms

As the permafrost thaws, the topography of the Arctic will alter dramatically, according to an international study headed by Finnish geographers. The study, which covered the entire area of permafrost in the Arctic, found ...

Siberia's permafrost erosion has been worsening for years

The Arctic is warming faster than any other region on the planet. As a result, permafrost that is thousands of years old is now being lost to erosion. As measurements gathered on the Lena River by AWI experts show, the scale ...

Peatland carbon and nitrogen stocks vulnerable to permafrost thaw

Northern peatlands hold large stocks of carbon and nitrogen and thus play a key role in global climate dynamics. However, their vulnerability to climate warming is uncertain, due in part to a lack of spatially explicit, observation-based ...

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Permafrost

In geology, permafrost, cryotic soil or permafrost soil is soil at or below the freezing point of water (0 °C or 32 °F) for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of the ground material. Most permafrost is located in high latitudes (i.e. land close to the North and South poles), but alpine permafrost may exist at high altitudes in much lower latitudes. Permafrost accounts for 0.022% of total water and exists in 24% of exposed land in the Northern Hemisphere.

The extent of permafrost can vary as the climate changes. Today, a considerable area of the Arctic is covered by permafrost (including discontinuous permafrost). Overlying permafrost is a thin active layer that seasonally thaws during the summer. Plant life can be supported only within the active layer since growth can occur only in soil that is fully thawed for some part of the year. Thickness of the active layer varies by year and location, but is typically 0.6–4 m (2.0–13 ft) thick. In areas of continuous permafrost and harsh winters the depth of the permafrost can be as much as 1,493 m (4,898 ft) in the northern Lena and Yana River basins in Siberia. Permafrost can also store carbon, both as peat and as methane. The most recent work investigating the permafrost carbon pool size estimates that 1400-1700 Gt of carbon is stored in permafrost soils worldwide. . This large carbon pool represents more carbon than currently exists in all living things and twice as much carbon as exists in the atmosphere.

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