Uncertainty in future solid ice discharge from Antarctica

• Main Authors: Winkelmann, R., Levermann, A., Frieler, K., Martin, M.
• Format: Report
• Language: English
• Published: 2012
• Subjects: Pik; Antarc*; Antarctica; Ice Sheet; The Cryosphere; The Cryosphere Discussions
• Online Access: http://hdl.handle.net/21.11116/0000-000D-A72F-3; http://hdl.handle.net/21.11116/0000-000D-A731-F

Future solid ice discharge from Antarctica under climate scenarios based on the Extended Concentration Pathways is investigated with the Potsdam Parallel Ice Sheet Model (PISM-PIK), a shallow model with a consistent representation of the ice flow in sheet, shelves and the transition zone. Both the uncertainty in the climate forcing as well as the intra-model uncertainty are combined into a probability distribution for solid ice discharge from Antarctica until the year 2500 under the ECP scenarios: All simulations are performed for a 81-member perturbed-physics ensemble and the likely ranges of surface and ocean warming under the emission pathways derived from the results of 20 CMIP3-AOGCMS. The effects of surface warming, ocean warming and increased precipitation on solid ice discharge are separately considered. We find that solid ice discharge caused by enhanced sub-shelf melting exceeds that caused by surface warming. Increasing precipitation leads to a change from net sea-level rise to sea-level drop. Our results suggest that the history of the ice-sheet plays an important role with respect to projections of solid ice discharge. Although all climate-change-forced simulations begin with the year 1850, the ice discharge around 2000 is significantly smaller than observed. Observed changes in ice discharge are reached around 2077 under the ECP-8.5 scenario. During the subsequent century, ice discharge reaches up to 0.24 m.