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

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. In Arctic mainland Norway, the plateau icefield Langfjordjokelen has experienced the greatest mass loss of all Norwegian glaciers (excluding Svalbard) in recent decades. In this article, we examine this decline in a centennial-scale context through geomorphological mapping and the analysis of historical aerial photographs and maps. This allows Langfjordjokelen’s maximum Little Ice Age extent (ca. 1925) to be reconstructed, providing an important baseline for a long-term assessment of icefield change. At the LIA maximum, Langfjordjokelen covered an area of 14.9 km2. A comparison of the LIA dimensions with the icefield extent in 1891/1902, as displayed on a historical map, reveals a substantial overestimation of the map-based glacier outline. The post-LIA evolution of Langfjordjokelen has been characterized by sustained high rates of glacier recession. By 2018, the icefield had lost 57% (8.5 km2) of its original LIA area, at a decadal rate of 9%, and its outlet glaciers had reduced in average length by 42% (1 km), at an annual rate of 11 m. Langfjordjokelen’s percentage area decline has been greater than that of Norwegian ice masses at lower latitudes where comparable long-term glacier change data are available. This indicates that there is a significant latitudinal variation in Norwegian glacier response to 20th century warming, likely influenced by an enhanced warming signal in Arctic Norway compared to the rest of the Norwegian mainland.