Degradation of the climate signal preserved in Svalbard ice archive

The whole Arctic regions is undergoing to a rapid warming, faster than the global average with a direct impact on all Arctic environmental sectors. Decrease in summer sea ice extension, changes in the atmospheric transport and composition, shorten the snow season and increasing the melting periods on the main Arctic Ice cap are just part of observed changes. The Svalbard archipelago is particularly sensitive to the temperature increasing due to its location and the moderate altitude of the main ice caps. Though the greater temperature rising has been observed during the winter periods, the enhanced summer temperatures are extending and prolonged in time the glaciated areas affecting by melting. Svalbard has four main ice caps: Austfonna, Lomonosofonna, Asgardfonna and Holthedalfonna. These ice fileds are situated between 800 m a.s.l. of Austfonna to the 1250 of the Lomosofonna and the Asgardfonna while the Holthedalfonna is located at 1100 m a.s.l.. Several ice cores have been recovered from this ice caps covering back to 1000 year ago. From 2012 to 2017 three shallow core, covering the periods 2016 - 2003 have been collected from the Holthedalfonna summit. The stable isotope datasets obtained have been compared with the longer ice core record collect in 2006 that extend back to the 17th century. Though the rise of the Arctic temperature, the shallow core shows a more negative stable isotopes value compare the long Holthedalfonna ice record. Meteorological measurements as well re-analysis conducted at the drilling site show a clear increasing of days with average temperature above zero, the increasing of summer melting and the strong decreasing of the summer snow accumulation. The combination of ice core data, meteorological re-analysis, mass balance calculation suggest that the Svalbard higher ice cap might have reach a tipping point where the summer accumulation is almost fully removed causing a bias on the isotopic signal. Thought the climate signal is still preserve in the buried ice the climatic signal recorded in the upper part cannot longer be compared and might representative only of winter deposition. These unique results underline the impact of Arctic amplification on Svalbard ice caps and the effect on climate signal preserved in its. Considering the similar altitude for the main Svalbard ice field, the results suggest that a tipping point might have been reached for the entire archipelago and, considering the likely temperature increase predicted for the close future, the impact detected might be extended to the older ice.