Glacier change in Norway since the 1960s – an overview of mass balance, area, length and surface elevation changes

Abstract

In this paper, we give an overview of changes in area, length, surface elevation and mass balance of glaciers in mainland Norway since the 1960s. Frontal advances have been recorded in all regions except the northernmost glaciers in Troms and Finnmark (Storsteinsfjellbreen, Lyngen and Langfjordjøkelen). More than half of the observed glaciers, 27 of 49, had marked advances in the 1990s. The glaciological mass-balance values for the period 1962–2018, where 43 glaciers have been measured, show great inter-annual variability. The results reveal accelerated deficit since 2000, the most negative decade being 2001–2010. Some years with a positive mass balance (or less negative) after 2010s can be attributed to variations in large-scale atmospheric circulation. A surface elevation change and geodetic mass balance were calculated for a sample of 131 glaciers covering 817 km2 in the ‘1960s’ and 734 km2 in the ‘2010s’, giving an area reduction of 84 km2, or 10%. The sample covers many of the largest glaciers in Norway, and they had an overall change in surface elevation of −15.5 m for the ~50 year period. Converted to a geodetic mass balance this gives a mean mass balance of −0.27 ± 0.05 m w.e. a−1.

Timing of Little Ice Age maxima and subsequent glacier retreat in northern Troms and western Finnmark, northern Norway

“…Of particular interest is the Langfjordjøkelen ice cap, where annual mass balance records are available from 1989. The Langfjordjøkelen mass balance records reveal mass deficits throughout the period of observation and higher glacier retreat rates compared to elsewhere in Norway (Andreassen, Kjøllmoen, et al 2012;Giesen et al 2014;Wittmeier et al 2015;Kjøllmoen 2019;Andreassen et al 2020).…”

“…In comparison, our results show a 39 percent reduction in glacier area over a shorter time frame (LIA maxima [~1814] to 1989). Comparatively, results from Langfjordjøkelen in western Finnmark have shown that this ice cap has experienced the highest rates of glacier shrinkage throughout Norway, with a marked reduction in length, area, and glaciological and geodetic mass balance (Andreassen et al 2020). Indeed, our data on Langfjordjøkelen reveal that glacier area reduced from 10.5 km 2 in 1989 to 6.8 km 2 in 2018, representing a 35 percent (3.7 km 2 ) reduction in area over the twentynine-year period.…”

Reconstructing the Little Ice Age extent of Langfjordjøkelen, Arctic mainland Norway, as a baseline for assessing centennial-scale icefield recession

“…Rates of frontal retreat accelerated to 13.4 m a -1 after 1988 and remained high between 1994 and 2006 (12.8 m a -1 ). Icefield recession in the 1988-1994 interval is in sharp contrast to the pronounced 1990s readvance of many other maritime glaciers along the Norwegian coast, which occurred in response to increased winter precipitation and a mass surplus in the late 1980s/early 1990s (Andreassen et al 2005(Andreassen et al , 2016Andreassen et al 2020;Nesje et al 2008;Kjøllmoen et al 2019). Although the available direct mass balance data from Langfjordjøkelen (Kjøllmoen et al 2019) also show high annual winter balances between 1989 and 1994 (and even slightly positive balance years in 1991/92 and 1992/93), summer ablation was often slightly higher (Fig.…”

“…Winsvold et al (2014) used the mapped outline to calculate glacier change to the year 2006 and found that Langfjordjøkelen had diminished in area and length by 62 and 43%, respectively. Modelling and geodetic measurements of Langfjordjøkelen's mass balance indicate a sustained decline of the icefield since the late 1940s (Andreassen, Kjøllmoen et al 2012;Kjøllmoen 2019;Andreassen et al 2020). Moreover, geodetic and direct mass balance measurements at the icefield (covering the periods 1966-2008 and 1989-2008, respectively) reveal the largest mass loss of all Norwegian glaciers with available mass balance records (Andreassen, Kjøllmoen et al 2012;Andreassen et al 2020).…”

“…1a), exhibited a net frontal retreat over the course of the 20th century (Andreassen et al 2005). This retreat has accelerated since the beginning of the 21st century (Weber et al 2019;Andreassen et al 2020). The last major expansion of ice masses in Norway occurred during the LIA (Grove 2004), with the Abstract Current warming in the Arctic is occurring at a rate two to three times higher than that of the rest of the world, leading to rapid glacier wastage.…”