In order to predict how much the sea level will rise in the future, it is crucial to accurately model ice sheets and their heat exchange with the surrounding ocean. In this project, we use the software Elmer/Ice as well as FEniCS to simulate ice sheets by solving the p-Stokes equations. We also model the ocean circulation close to the ice sheet by solving the Boussinesq equations. These problems are both non-linear and involve moving interfaces. We develop numerical methods to run efficient and stable simulations. In the previous Medium project NAISS 2024/5-210 we did initial simulations of the ocean using FEniCS in 2D, and we now plan to make more complex simulations in 3D, which will be more computationally expensive. Furthermore, we simulated grounding line migration and ice shelves in 2D and 3D, with a high resolution with Elmer/Ice. These simulations are particularly expensive as a high spatial resolution and the full p-Stokes equations (rather than ice-flow approximations) are needed due to complicated ice-flow physics at the grounding line.