Permafrost is rock, sediment, ice or mixtures of such with a temperature that has remained at or below 0ºC for two or more consecutive years. Permafrost is considered continuous in Svalbard (except beneath large glaciers) and is widespread in the high mountains of Norway. As permafrost may contain bodies of ground ice, thawing of permafrost can lead to subsidence of the ground surface, having a substantial impact on infrastructures and on the stability of the land surface itself.
This concern is highlighted by global climate models that project substantial future increases in temperature in northern high latitudes as a response to increases in greenhouse concentrations. For that reason, IPCC advocated that research should be directed towards defining the climate-permafrost relation, including the effects of temperature forcing from climatic variation, local environmental factors such as snow and vegetation, and ground materials or bedrock types. Permafrost has also been identified as one of six cryospheric indicators of global climate change within the international framework of the WMO Global Climate Observing System (GCOS). Recently, attention was again drawn to the coupling between future climate change in the Arctic and associated changes in permafrost by ACIA (2005).
Most geomorphological processes and heat flow conditions at shallow depths below the ground surface are directly influenced by climate and will be affected by future climatic changes. The coupling between climate, permafrost and associated geomorphological processes is, however, not simple and straightforward, as some simplistic initial analyses might appear to suggest. In addition, there might well be significant regional differences, controlled by differences in seasonality, topography, bedrock type, snow cover characteristics and vegetation. Hence, in order to fully exploit the potential of climate projections to generate projections of future permafrost temperatures in Svalbard and Norway, it is essential to conduct a detailed analysis of how air temperatures are transmitted into the ground in various key regions, using meteorological records and observations on snow cover and ground temperatures.
The main contribution of TSP NORWAY to the IPY will be the development of a spatially distributed set of observations on past and present status of permafrost temperatures and active layer thicknesses in Svalbard and Norway. Emphasis is on permafrost temperatures since there is currently no global database that defines the thermal state of permafrost (TSP) for a specific time period (snapshot).
The TSP NORWAY data set will serve as a baseline for:
The assessment of the rate of change of permafrost temperatures and
Permafrost distribution,
Validating climate model scenarios,
Supporting process research to improve our understanding of permafrost dynamics.
The permafrost thermal regime between 10 m and 200 m depth is often considered a useful indicator of the decade-to-century climatic variability and long-term changes in the surface energy balance. The range of the interannual temperature variations (“noise”) decreases significantly with depth, while decadal and longer time-scale variations dominate at greater depths in permafrost. This makes temperature-depth profiles in permafrost potential means of analysing past temperature changes at the ground surface.
Many potential environmental and socioeconomic impacts of global climatic change are associated with permafrost. The effects of climatic change on permafrost and the seasonally thawed layer above it, the active layer, can severely disrupt ecosystems and human infrastructure and intensify global warming. Until recently, however, permafrost has received far less attention in scientific reviews and media publications than other cryospheric phenomena (e.g. glaciers) affected by global change. Permafrost degradation may affect slope stability, and to evaluate certain geohazards (rock slides and mudflows), such as investigated by the Norwegian Research Council funded GeoExtreme project (coordinated by TSP NORWAY participant Lars H. Blikra), improved knowledge on the permafrost is essential to increase the understanding of geohazards in Norway and Svalbard.
In Norway permafrost represents a significant feature of the landscape. According to the first modelling attempts, permafrost today underlies about 2800 km2 of the land area south of Trondheim. By comparison, the present glacier cover in southern Norway is only about 1600 km2. In Svalbard, virtually all land areas without permanent ice (32000 km2) cover is underlain by permafrost. The proportion of permafrost in Norway (incl. Svalbard) is highest among European countries.