We evaluate the impact of the increased snowmelt on the preservation of the oxygen isotope (δ¹⁸O) signal in firn records recovered from the top of the Holtedahlfonna ice field located in the Svalbard archipelago. Thanks to a multidisciplinary approach we demonstrate a progressive deterioration of the isotope signal in the firn core. We link the degradation of the δ¹⁸O signal to the increased occurrence and intensity of melt events associated with the rapid warming occurring in the archipelago.