How will permafrost affect and be affected by global environmental change?

Permafrost is defined as ground that remains at or below 0°C for at least two consecutive years. Permafrost underlies approximately 25 % of the land area in the northern hemisphere and can be up to 1500 m thick. Under current climate-change scenarios, permafrost degrades from both the top and bottom, increasing the depth of the “active layer”, and the extent of talik formation.

The deepening of the active layer could trigger the massive decomposition of organic matter stored in the first three meters below surface. The most recent estimates put the organic carbon pool in permafrost at 50% of the global soil organic carbon pool. This pool is equivalent to twice the amount of carbon in the atmosphere. The decomposition processes would lead to the emission of vast quantities of greenhouse gases, including methane and carbon dioxide, which could greatly affect the global climate.

Under the sea, permafrost occurs as subsea permafrost. Its presence on Arctic shelves is intrinsically linked to the occurrence of gas hydrates which are released to the atmosphere through “holes” in the permafrost, called gas seeps. Its exact distribution on the shelves of the Arctic has not yet been correctly assessed, which hampers the attempts to correctly depict the mechanisms of gas hydrate occurrence and release.

In alpine areas, permafrost is responsible for the occurrence and the preservation of landforms that could evolve dramatically, resulting in large scale natural hazards for alpine valley settlements. In the Arctic, rapid coastal erosion of permafrost is expected to increase dramatically following the drastic reduction of summer sea ice extent, threatening the existence of Inuit communities.

Permafrost observation and monitoring is probably one of the most important challenges of the twenty-first century

More information on theIPA website

One comment

1. vonder says:

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   Permafrost is for two main reasons of utmost importance:
   (1) degrading circumpolar permafrost areas contribute by releasing greenhouse gases to a complex and dynamically accelerating feedback effects
   (2) mountain but also circumpolar permafrost areas undergo various types of new and increased numbers of natural hazards (rock falls, debris flows, instable ground, etc)

   Both types can only be tackles by an interdisciplinary and international approach integrating knowledge of various experts