Additional contributions to CMIP5 Regional Sea Level Projections resulting from Greenland and Antarctic Ice Mass Loss

The impact of Greenland and Antarctic ice sheet mass loss on regional sea level is evaluated here under RCP 4.5 and RCP 8.5 scenarios for the period 2081–2099. To this end, estimates of associated fresh water sources are added to the Max Planck Institute for Meteorology's Earth System Model ocean component and the dynamical impact is quantified in terms of the difference in sea level relative to previous phase 5 of the Coupled Model Intercomparison Project runs. Overall, the addition of these freshwater sources have only a small impact on regional sea level variations relative to the global mean (<2 cm in magnitude). However, in some regions, notably in the North Atlantic and Arctic Ocean, an additional increase in regional steric sea level by 4–8 cm can be obtained, which is ~20% more than the previous climate model response. Climate feedbacks can have additional sea level impacts regionally, e.g., through changes in the wind forcing or surface freshwater fluxes. Overall, the dynamical regional sea level response to the polar ice mass loss is of the same order as the simulated decadal sea level variability.