• Energy Research

The high Arctic archipelagos around the globe are among the most strongly glacierized landscapes on Earth apart from the Greenland and Antarctic ice sheets. Over the past decades, the mass losses from land ice in the high Arctic regions have contributed substantially to global sea level rise. Among these regions, the archipelago of Svalbard showed the smallest mass losses. However, this could change in the coming decades, as Svalbard is expected to be exposed to strong climate warming over the 21st century. Here we present extensive Monte Carlo simulations of the future ice-mass evolution of 29 individual land-terminating glaciers on the Svalbard archipelago under an RCP 8.5 climate forcing. An extrapolation of the 29 sample glaciers to all land-terminating glaciers of the archipelago suggests an almost complete deglaciation of the region by 2100. Under RCP 8.5, 98% of the land-terminating glaciers will have declined to less than one tenth of their initial size, resulting in a loss of 7392 ± 2481 km ^2 of ice coverage.

Scientific reports 5, 8079 (2015). doi:10.1038/srep08079 Published by Nature Publishing Group, London

Relatively little is known about the glacier mass balance of Svalbard in the first half of the twentieth century. Here, we present the first century-long climatic mass balance time series for the Svalbard archipelago. We use a parameterized mass balance model forced by statistically downscaled ERA-20C data to model climatic mass balance for all glacierized areas on Svalbard with a 250 m resolution for the period 1900–2010. Results are presented for the archipelago as a whole and separately for nine different subregions. We analyze the extent to which climatic mass balance in the different subregions mirror the temporal evolution of the climate warming signal, especially during the early twentieth century Arctic warming episode. The spatially averaged mean annual climatic mass balance for all Svalbard is balanced at −0.002 m w.e. with an associated mean equilibrium line altitude of 425 m a.s.l. When also taking calving fluxes into account, this status leads to an archipelago-wide cumulative mass balance of −16.9 m w.e. over the study period, equaling a sea level equivalent of ~1.6 mm. The long-term evolution of climatic mass balance is largely governed by ablation variability. Refreezing contributes 34% to the archipelago-wide mass gain on average. Considerable variability is evident across Svalbard, with predominantly positive climatic mass balances in the northeastern parts of the archipelago and mostly negative ones in the western and southern parts. The archipelago-wide climatic mass balance shows a statistically significant trend of −0.021 m w.e. per decade and the associated equilibrium line altitude rises with a likewise significant trend of +3.0 m a.s.l. per decade. Spatial variability of the equilibrium line is such that the lowest altitudes are reached across the eastern islands of the archipelago and the highest ones in the central parts of Spitsbergen.