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

Liss M. Andreassen,Joaquín M. C. Belart,Bjarne Kjøllmoen,Hallgeir Elvehøy

doi:10.1017/jog.2020.10

Liss M. Andreassen, Joaquín M. C. Belart + Show 2 more

Open Access

https://doi.org/10.1017/jog.2020.10

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Abstract

AbstractIn 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.

Highlights

Glaciers in Norway cover 0.7% of the land area and have importance for hydropower, water management and tourism
The uncertainty will vary from the different maps due to snow conditions etc, here we compare two independent datasets derived from the same aerial photographs from 1966 of Austre and Vestre Memurubrean in the Jotunheimen region (Fig. 1)
The ice divide of Hellstugubreen/Vestre Memurubrean vary, as the one digitised from the orthophotos used the current ice divide calculated from the laser scanning of 2009, instead of the one used for the calculations at the time of the mass-balance measurements

Summary

Introduction

Glaciers in Norway cover 0.7% of the land area and have importance for hydropower, water management and tourism. Studies have shown that it is possible to get annual and even seasonal signals from the geodetic method (Geist and others, 2005; Belart and others, 2017; Klug and others, 2018), a repeated survey every decade is recommended for glaciological mass-balance programmes (Zemp and others, 2013). With such a period, standard density conversions can in most cases be used to convert from elevation changes to mass balance (Huss, 2013). Knowledge of regional similarities and differences is valuable to check the representability of glaciers with long-term mass-balance programmes

Results

Discussion

Conclusion