https://doi.org/10.5194/tc-2021-173 Preprint. Discussion started: 11 June 2021 c Author(s) 2021. CC BY 4.0 License. Nunataks as barriers to ice flow: implications for palaeo ice-sheet reconstructions Martim Mas e Braga1,2, Richard Selwyn Jones3,4, Jennifer C. H. Newall1,2, Irina Rogozhina5, Jane L. Andersen6, Nathaniel A. Lifton7,8, and Arjen P. Stroeven1,2 1Geomorphology & Glaciology, Department of Physical Geography, Stockholm University, Stockholm, Sweden 2Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden 3Department of Geography, Durham University, Durham, UK 4School of Earth, Atmosphere and Environment, Monash University, Melbourne, Australia 5Department of Geography, Norwegian University of Science and Technology, Trondheim, Norway 6Department of Geoscience, Aarhus University, Aarhus, Denmark 7Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, USA 8Department of Physics and Astronomy, Purdue University, West Lafayette, USA Correspondence: Martim Mas e Braga (
[email protected]) Abstract. Numerical models predict that discharge from the polar ice sheets will become the largest contributor to sea level rise over the coming centuries. However, the predicted amount of ice discharge and associated thinning depends on how well ice sheet models reproduce glaciological processes, such as ice flow in regions of large topographic relief, where ice flows around bedrock summits (i.e. nunataks) and through outlet glaciers. The ability of ice sheet models to capture long-term ice loss is 5 best tested by comparing model simulations against geological data. A benchmark for such models is ice surface elevation change, which has been constrained empirically at nunataks and along margins of outlet glaciers using cosmogenic exposure dating.