Geoid height perturbations due to diffusion creep in the shallow upper mantle for the RSES ice-load history (DIF-STD, a) and the ICE-5G ice-load history (DIFi-STDi, b). In (b), the area within the contour is robust to changes in the ice-load history with a standard deviation (of predictions DIF-STD and DIFi-STDi) smaller than 20 cm and a mean larger than 40 cm.