The reological properties of the crust and the upper mantle beneath Iceland make the earth surface sensitive to recent ice mass changing. On a short time scale, strong correlation exists between seasonal variations in continuous GPS time series and snow covering. The overall retreat of Icelandic glaciers is causing uplift of over 2 cm/yr around Vatnajökull, the largest Icelandic ice cap. Recent modelling also suggests that the same phenomena is causing increased mantle melting and magma generation under Vatnajökull