| Summary: | International audience Environmental mass redistribution, including the recent and past ice melting, induces Earth’s surface deformations as well as time variations in its gravity field. These effects are known as loading effects and can be accurately monitored using space geodesy techniques. In this study, we analyse more than 20 years of GNSS (Global Navigation Satellite System) satellite 3D positioning solutions at 17 permanent sites over the Svalbard archipelago. The results are compared with deformations computed from time gravity field variations observed by the space gravimetry missions GRACE (Gravity Recovery and Climate Experiment) and GRACE-Follow On. The combination of these two techniques takes advantage of their complementary temporal and spatial resolutions, helping to distinguish between local, regional, and global signals. Our results indicate that the mean vertical motion is of about 9 mm/year upward and can reach 15 mm/yr in some places. We show that most of the loading signal is due to local effects. We then compare these GNSS and GRACE datasets with Little Ice Age (LIA) and Global Isostatic Adjustment (GIA) models as well as with satellite altimetry observations from CryoSat 2 and IceSat¬¬ 2. These comparisons allow us to separate the various contributions and to estimate the impact of the current climate change on Svalbard. The results are then discussed in relation to in situ observations.
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