Deformation and gravity fields can be used to trace various processes in the earth system. A well-known example of such processes is the glacial-isostatic adjustment of the viscoelastic earth. Apart from the adjustment caused by the melting of the Pleistocene ice sheets, effects due to the present ice-mass imbalances in Antarctica, Greenland, Alaska and elsewhere have received increased attention over the last decade. The main motivation of glacial-isostatic adjustment studies are the estimation of the mantle viscosity, including its radial and lateral variations, and the determination of the global sea-level rise associated with the current climate warming. The talk presents an overview of the modelling work completed at the GeoForschungsZentrum Potsdam as part of the SEAL (Sea Level Change) project. In particular, examples are presented showing the complicated interplay between Pleistocene and present glacial changes, mantle viscosity, relative sea-level and global sea-level rise.