Landscape transformation under the Gåsbreen glacier recession since 1899, southwestern Spitsbergen

Abstract

Landscape changes of the Gåsbreen glacier and its vicinity since 1899 are described. Maps at 1:50 000 scale of changes of the glacier's elevation and extent for the periods 1938-1961, 1961-1990, 1990-2010, and 1938-2010 are analyzed in comparison with results of the authors' field work in the summer seasons 1983, 1984, 2000, 2005 and 2008. During all the 20th century, the progressive recession of the glacier revealed in a dramatic decrease in the thickness of its lower part, with a small reduction of its area and length. However, further shrinkage produced significant shortening and reduction in area which resulted in final decline of the Goësvatnet glacial dammed lake in 2002. Hence, the lowest (and very thick, up to 150-160 m) part of the former glacier tongue and dammed lake were transformed into a new terraced river valley south of the glacier and a typical marginal zone with glacial landforms north of the glacier. Since 1961, the equilibrium line altitude of the Gåsbreen glacier has risen from ca 350 to ca 500 m a.s.l. and now is located below the very steep rocky walls of the Mehesten mountain ridge, 1378 m a.s.l. Hence, the glacier is being fed by snow avalanches from these rocky walls and much more snow melts during the warmer summer seasons, stimulating a quicker recession of the lowest part of the glacier. This recession may be stopped only by significant climate cooling or increase in snow.

Inventory and classification of the post Little Ice Age glacial lakes in Svalbard

“…There is limited knowledge on glacial lakes and their changes in Svalbard. Lake Goësvatnet, situated in northern Sorkappland, is the best documented glacial lake, but it ceased to exist in 2001 because of the retreat of Gåsbreen, followed by a glacial flood (Grzes and Banach, 1984;Schoner and Schoner, 1997;Ziaja et al, 2016). Up to date, there is no data on the number and area of glacial lakes, and their spatial distribution and temporal changes.…”

“…Goësvatnet is the best documented ice-dammed lake in Svalbard (NW Sørkapp Land). During the summer season, the lake drained through a tunnel located in the transition zone between dead ice and active glacier ice of Gåsbreen -Goësvatnet was observed for the last time in 2000 (Grzes and Banach, 1984;Schoner and Schoner, 1997;Ziaja et al, 2016;Ziaja and Ostafin, 2007). Observations of ice-dammed lakes in satellite and aerial photographs indicate that considerable GLOF events can be expected in the coming years due mostly to the large amounts of water accumulated behind ice dams which according to the glaciers retreat on Svalbard will gradually vanish (Huss et al, 2009;Sobota, 2014;Zemp et al, 2012).…”

Fifty Years of Tidewater Glacier Surface Elevation and Retreat Dynamics along the South-East Coast of Spitsbergen (Svalbard Archipelago)

“…Precise historic geographic data are rather sparse in the high Arctic and most of the information on glacier dynamics is usually limited to the last 20 or 30 yearswhen remote sensing data has become more readily available [18][19][20][21][22], or are limited to a single glacier where past direct observational data are available [23][24][25]. Members of the glaciological community are trying to bridge the gap by using different modelling approaches [12,26,27].…”

Deglaciation Rate of Selected Nunataks in Spitsbergen, Svalbard—Potential for Permafrost Expansion above the Glacial Environment

“…The results described here follow recent observations of glacier surface lowering in Svalbard due to global warming. This phenomenon is more intense for the lower glacier sections [45][46][47][48][49][50][51]. This is associated with a possible expansion of the periglacial zone at high altitudes, from the top of ridges and nunataks down the slopes.…”