Permafrost in Svalbard: a Review of Research History, Climatic Background and Engineering Challenges
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Permafrost in Svalbard: a review of research history, climatic background and engineering challenges Ole Humlum, Arne Instanes & Johan Ludvig Sollid This paper reviews permafrost in High Arctic Svalbard, including past and current research, climatic background, how permafrost is affected by climatic change, typical permafrost landforms and how changes in Svalbard permafrost may impact natural and human systems. Informa- tion on active layer dynamics, permafrost and ground ice characteristics and selected periglacial features is summarized from the recent literature and from unpublished data by the authors. Permafrost thickness ranges from less than 100 m near the coasts to more than 500 m in the highlands. Ground ice is present as rock glaciers, as ice-cored moraines, buried glacial ice, and in pingos and ice wedges in major valleys. Engineering problems of thaw-settlement and frost-heave are described, and the impli- cations for road design and construction in Svalbard permafrost areas are discussed. O. Humlum, Dept. of Physical Geography, Institute of Geosciences, University of Oslo, Box 1042 Blindern, NO-0316 Oslo, Norway, and Dept. of Geology, University Centre in Svalbard, NO-9170 Longyearbyen, Norway, [email protected]; A. Instanes, Instanes Consulting Engineers, Storetveitveien 96, NO-5072 Bergen, Norway; J. L. Sollid, Dept. of Physical Geography, Institute of Geosciences, University of Oslo, Box 1042 Blindern, NO-0316 Oslo, Norway. Recent changes in the Arctic atmosphere–ice– high climatic sensitivity of the Arctic (Giorgi ocean system have sparked intense discussions 2002). Recently, however, Polyakov, Akasofu et as to whether these changes represent episodic al. (2002) and Polyakov, Alekseev et al. (2002) events or long-term shifts in the Arctic environ- presented updated observational trends and vari- ment. Concerns about future climate change stem ations of Arctic climate and sea ice cover during from the increasing concentration of greenhouse the 20th century which do not support the mod- gases in the atmosphere. During the last 15 years elled polar amplifi cation of temperature changes the Arctic has gained a prominent role in the sci- observed by surface stations at lower latitudes. entifi c debate regarding global climatic change There is reason, therefore, to evaluate cli- (Houghton et al. 2001). Existing knowledge on mate dynamics and their respective impacts on Quaternary climate and Global Climate Models high latitude ecosystems, including permafrost predicts that the effect of any present and future regions. The latter currently occupies 20 - 25 % global climatic change would be amplifi ed in the of the land surface of the Northern Hemisphere polar regions due to feedbacks in which variations (Péwé 1983; Zhang et al. 2000). Slight chang- in the extent of glaciers, snow, sea ice, permafrost es in mean annual air temperature, wind speed and atmospheric greenhouse gases play key roles. and precipitation have the potential to change the Recent subcontinental-scale analysis of meteor- state of large regions of currently frozen ground ological data obtained during the observation- (Nelson et al. 2001, 2002; Anisimov et al. 2002). al period lends empirical support to the alleged Humlum et al. 2003: Polar Research 22(2), 191–215 191 Fig. 1. Map of the Svalbard archipelago (small, southern island of Bjørnøya not shown), showing the position of places referred to in the text. Grey indicates permafrost areas (ca. 25 000 km2) without ice cover. Svalbard permafrost research surface at Kapp Thordsen in 1883. He was able to demonstrate temperature variations to a depth of 2 m. Later, Holmsen (1913) studied ground ice This section outlines research on permafrost in in Colesdalen, central Spitsbergen. Observing Svalbard, an archipelago of 63 000 km2 (Fig 1), ground ice at several sites below the upper marine since the late 19th century. This example of an limit, he was probably the fi rst to demonstrate a early international research effort was, especial- late Holocene age for permafrost and ground ice ly during the fi rst years, dominated by Nordic at low altitudes in Svalbard. researchers. Some of the publications referred Werenskiold (1922) published the fi rst review of to below are published in Norwegian or other frozen ground phenomena in Spitsbergen. Other Nordic languages only. As such, they are not early observations relating to Svalbard perma- always easily accessible to an international audi- frost were carried out by Huxley & Odell (1924), ence. The research focus has traditionally been Gripp (1926), Elton (1922, 1927) and Kulling on the main island, Spitsbergen. Among many (1937). From measurements of fi rn temperatures fi ne scientists, one in particular stands out: Olav in the accumulation area of Fjortende Julibreen, Liestøl (1916–2002), who provided ideas and Sverdrup (1935) was presumably one of the fi rst inspiration for many Nordic permafrost scientists to demonstrate that bedrock below large glaciers active in Svalbard. in Svalbard does not necessary need to be frozen. Permafrost was known to be present in Sval- Orvin (1941) published descriptions of horizontal bard at least since the First International Polar layers of ground ice (presumably refrozen ground Year in 1882 and the fi rst coal mining operations water) from Spitsbergen. Later, Orvin (1944) in 1898. Ekholm (1890) measured ground tem- addressed the apparent paradox of explaining peratures at different depths below the terrain permanent springs in a region with extensive per- 192 Permafrost in Svalbard: a review ennial frozen ground. cal aspects have also been addressed by several Liestøl (1962) described so-called “talus ter- workers, especially in relation to water supply at races” from various sites in Svalbard. These the Large-scale Research Facility in Ny-Ålesund, rock-glacier-like features were described as north-west Spitsbergen (e.g. Lauritzen 1991; consisting of recurrent layers of ground ice and Sandsbråten 1995; Haldor sen et al. 1996; Booij et debris, exposed to permafrost creep. Jahn (1960, al. 1998; Haldorsen & Heim 1999). 1965, 1967) described slope evolution, patterned The vertical temperature profi le of thick per- ground, solifl uction, rock falls and avalanches, mafrost has recently been recognized as an including the June 1953 avalanche disaster in important means of obtaining information on Longyearbyen. Jahn (1976) and Larsson (1982) past surface temperatures. This is the object of both described another catastrophic mass move- a joint European research initiative, Permafrost ment event that affected Longyearbyen during a and Climate in Europe (PACE), that has estab- heavy rainstorm in August 1972. This event was lished a number of permafrost monitoring sites due to saturation of unconsolidated near-surface in a north–south European transect (Sollid et al. sediments (the active layer) by heavy rain. 2000; Isaksen et al. 2001; Isaksen, Humlum & Liestøl (1976) was the fi rst systematically to Sollid 2003). The northernmost site is located consider the thickness and thermal conditions of on Janssonhaugen, in upper Adventdalen, central Svalbard permafrost. This classic paper describes Spitsbergen. The temperature profi le from the the distribution of pingos, springs and permafrost more than 100 m deep borehole clearly demon- in Spitsbergen. From observations made during strates the effect of a marked 20th century warm- mining operations, he was able to estimate the ing around 1920 as well as later meteorological magnitude of the geothermal gradient—about variations (Isaksen, Ødegård et al. 2000; Isaksen, 2 - 2.5 °C/100 m in central Spits berg en. Péwé Vonder Mühll et al. 2000; Isaksen 2001; Isaksen, (1979) and Péwé et al. (1981) also discussed Sval- Humlum, Sollid et al. 2003). bard permafrost in relation to climate and ongo- Pingos are well-known phenomena in Sval- ing mining operations. bard. Svensson (1971) gave the fi rst detailed Several other papers merit identifi cation in description, based upon observations made in this review. For example, Liestøl (1976, 1980, Adventdalen, near Longyearbyen. It was possible 1986) measured permafrost temperatures and to obtain a maximum age for pingo initiation of permafrost thickness in several deep boreholes about 2650 yr BP, suggesting a late Holocene age on Spitsbergen, while Gregersen & Eidsmoen for permafrost near sea level in the region. The (1988) studied near-shore permafrost conditions distribution and formation of pingos in Svalbard at Longyearbyen and Svea. Salvigsen & Elgers- was further described and discussed in a semi- ma (1985) and Salvigsen et al. (1983) discussed nal paper by Liestøl (1976). Yoshikawa & Harada the issue of taliks and karst features in perma- (1995) present additional observations on the rate frost in relation to large glaciers, major lakes or and timing of pingo growth in central Spitsber- warm groundwater springs. Lauritzen & Bottrell gen. Salvigsen (1977) and Åkerman (1982, 1987) (1994) described microbiological activity in some discuss the sporadic occurrence of palsas in Sval- of these Svalbard springs. Finally, Landvik et al. bard. (1988) discussed the possible occurrence of sub- Ice wedges represent another typical example marine permafrost on the shelf around Svalbard of geomorphic permafrost phenomenon present from a glacial-isostatic point of view. in Svalbard (Svensson 1976). They have been The Norwegian Committee on Permafrost the object of intermittent research, often in asso- established the fi rst site for Arctic engineering ciation with