C062-0005
Reduced Mass Loss from the Greenland Ice Sheet under Stratospheric Aerosol Injection
Wednesday, 16 December 2020
Poster
Ralf Greve1,2, John C Moore3,4, Thomas Zwinger5, Fabien Gillet-Chaulet6, Chao Yue3 and Liyun Zhao3,7, (1)Hokkaido University, Institute of Low Temperature Science, Sapporo, Japan, (2)Hokkaido University, Arctic Research Center, Sapporo, Japan, (3)Beijing Normal University, College of Global Change and Earth System Science, Beijing, China, (4)University of Lapland, Arctic Centre, Rovaniemi, Finland, (5)CSC - IT Center for Science, Espoo, Finland, (6)Grenoble Alpes University, CNRS, IRD, IGE, Grenoble, France, (7)Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
Abstract:
Stratospheric aerosol injection (SAI) has been proposed as a potential method of mitigating some of the adverse effects of anthropogenic climate change, including sea-level rise from the ice sheets. In this study, we use the SICOPOLIS (www.sicopolis.net) and Elmer/Ice (elmerice.elmerfem.org) dynamic models driven by changes in surface mass balance and temperature to estimate the sea-level-rise contribution from the Greenland ice sheet under the IPCC RCP4.5, RCP8.5 and GeoMIP G4 (Kravitz et al., 2013, doi: 10.1002/2013JD020569) scenarios. The G4 scenario adds 5 Tg/yr sulfate aerosols to the equatorial lower stratosphere to the IPCC RCP4.5 scenario.
Figure 1 shows the 2090-2015 mass loss of the Greenland ice sheet under the three scenarios with four earth system models, simulated with the SICOPOLIS model (hybrid shallow-ice-shelfy stream dynamics) and the Elmer/Ice model (Elmer/Ice-sheet set-up, shelfy stream dynamics). The results from the two ice-sheet models are very similar. Relative to the constant-climate control simulations (CTRL), the losses from 2015 to 2090 are 64 [53, 80] mm SLE for RCP8.5, 46 [38, 53] mm SLE for RCP4.5 and 28 [18, 39] mm SLE for G4 (mean and full range). Thus, the mean mass loss under G4 is about 38% smaller than that under RCP4.5 and 56% smaller than that under RCP8.5. For both models, the accumulated SMB is larger than the actual ice loss. This is so because, in more extreme climate scenarios, the ice sheet recedes further from the coast, thereby reducing mass loss due to calving. This negative feedback is stronger in Elmer/Ice than in SICOPOLIS, likely related to the higher resolution of Elmer/Ice's finite-element mesh compared to SICOPOLIS's regular finite-difference grid near the ice margin.
