Climate change is rapidly deteriorating the climatic signal in Svalbard glaciers

Abstract

Abstract. The Svalbard archipelago is particularly sensitive to climate change due to the relatively low altitude of its main ice fields and its geographical location in the higher North Atlantic, where the effect of the Arctic Amplification is more significant. The largest temperature increases have been observed during winter, but increasing summer temperatures, above the melting point, have led to increased glacier melt. Here, we evaluate the impact of this increased melt on the preservation of the oxygen isotope signal (δ18O) in firn records. δ18O is commonly used as proxy for past atmospheric temperature reconstructions and, when preserved, it is a crucial parameter to date and align ice cores. By comparing four different firn cores collected in 2012, 2015, 2017 and 2019 at the top of the Holtedahlfonna ice field (1100 m. a.s.l.), we show a progressive deterioration of the isotope signal and we link its degradation to the increased occurrence and intensity of melt events. Although the δ18O signal still reflects the interannual temperature trend, more frequent melting events may in the future affect the interpretation of the isotopic signal, compromising the use of Svalbard ice cores. Our findings highlight the impact and the speed at which Arctic Amplification is affecting Svalbard's cryosphere.