GeoMIP scenarios applied to the Greenland ice sheet
Stratospheric Aerosol Injection (SAI) is a highly debated topic. The more it is important to look into the science (objectively, without an agenda). In order to contribute to this process, two ice dynamic models (SICOPOLIS and Elmer/Ice) driven by changes in surface mass balance (SMB) from four climate models to estimate the SLR contribution under the Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathway (RCP) 4.5, and 8.5, and Geoengineering Model Intercomparison Project G4 scenarios were deployed for the Greenland ice sheet. The G4 scenario adds 5 Tg/yr sulfate aerosols to the equatorial lower stratosphere (equivalent of 1/4 the 1991 Mt Pinatubo SO2 eruption) to the IPCC RCP4.5 scenario, which itself approximates the greenhouse gas emission commitments agreed in Paris in 2015. In the applied setups for the 2020–2090 period, the two ice sheet models show a reduction of mass loss between 31%–38% for the G4 compared to RCP4.5 scenario, which itself compared to RCP8.5 shows a lowering of 36%–48%. Both, the G4 and the 4.5 scenario indicate a lowering of the ice-flux across the grounding line into the ocean, as glaciers retreat from the coast and become land-terminated, with an exception of low-lying catchments (e.g., Jakobshavn, 79N, Zachariae Isstrøm, and Petermann glaciers) that show an increased flux under RCP 4.5 compared to G4. Despite a dominating variation of calving losses compared to differences in SMB between SICOPOLIS and Elmer/Ice, ice discharge losses are significant, ranging from 15% up to 42%, depending on the scenario. Picture (taken from the publication) to the right shows differences of the ensembles in flux and ice thickness between G4 and RCP4.5 runs.
Read more:
Moore, J. C., R. Greve, C. Yue, T. Zwinger, F. Gillet-Chaulet, and L. Zhao, 2023. Reduced Ice Loss From Greenland Under Stratospheric Aerosol Injection. Journal of Geophysical Research: Earth Surface, 128. doi:10.1029/2023JF007112
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