Low elevation of Svalbard glaciers drives high mass loss variability

• Published in: Nature communications Vol. 11; no. 1; p. 4597
• Main Authors: Noël, Brice, Jakobs, C. L., van Pelt, W. J. J., Lhermitte, S., Wouters, B., Kohler, J., Hagen, J. O., Luks, B., Reijmer, C. H., van de Berg, W. J., van den Broeke, M. R.
• Format: Journal Article Web Resource
• Language: English; Norwegian
• Published: London Nature Publishing Group UK 14.09.2020; Nature Publishing Group; Nature Research; Nature Portfolio
• Subjects: 704/106/125; 704/106/694/1108; Accumulation; Amplification; Biochemistry, Genetics and Molecular Biology (all); Chemistry (all); Climate models; Current distribution; Earth sciences & physical geography; Firn; General Biochemistry, Genetics and Molecular Biology; General Chemistry; General Physics and Astronomy; glacier; Glaciers; Glaciohydrology; High resolution; Humanities and Social Sciences; Hypsometry; Ice; mass loss; Meltwater; modelling; Multidisciplinary; Physical, chemical, mathematical & earth Sciences; Physics and Astronomy (all); Physique, chimie, mathématiques & sciences de la terre; Polar environments; Runoff; Science; Science (multidisciplinary); Sciences de la terre & géographie physique; Sea level; Svalbard; Arctic region
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-18356-1

Compared to other Arctic ice masses, Svalbard glaciers are low-elevated with flat interior accumulation areas, resulting in a marked peak in their current hypsometry (area-elevation distribution) at  ~450 m above sea level. Since summer melt consistently exceeds winter snowfall, these low-lying glaciers can only survive by refreezing a considerable fraction of surface melt and rain in the porous firn layer covering their accumulation zones. We use a high-resolution climate model to show that modest atmospheric warming in the mid-1980s forced the firn zone to retreat upward by  ~100 m to coincide with the hypsometry peak. This led to a rapid areal reduction of firn cover available for refreezing, and strongly increased runoff from dark, bare ice areas, amplifying mass loss from all elevations. As the firn line fluctuates around the hypsometry peak in the current climate, Svalbard glaciers will continue to lose mass and show high sensitivity to temperature perturbations. Svalbard glaciers are among the lowest ice masses in the Arctic, with a peak in glacier area below 450 m elevation. Using a high-resolution climate model, here the authors show that a modest warming in the mid-1980s propagated meltwater runoff above the glacier area peak, amplifying Svalbard mass loss from all elevations.