EGU2020-19692, updated on 20 Jan 2021
https://doi.org/10.5194/egusphere-egu2020-19692
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Coupled ice-climate simulation of future Greenland ice sheet evolution: mechanisms, thresholds and feedbacks for accelerated mass loss

Miren Vizcaino1, Laura Muntjewerf1, Raymond Sellevold1, Carolina Ernani da Silva1, Michele Petrini1, Katherine Thayer-Calder2, Meike Scherrenberg1, Sarah Bradley3, Jeremy Fyke4, William Lipscomb2, Marcus Lofverstrom5, and William Sacks2
Miren Vizcaino et al.
  • 1Delft University of Technology, Geoscience and Remote Sensing, Delft, Netherlands (m.vizcaino@tudelft.nl)
  • 2Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
  • 3Department of Geography, The University of Sheffield, Sheffield, UK
  • 4Associated Engineering Group Ltd., Calgary, Alberta, Canada
  • 5Department of Geosciences, University of Arizona, Tucson, Arizona, USA

The Greenland ice sheet (GrIS) has been losing mass in the last several decades, with a current contributing of around 0.7 mm per year to global mean sea level rise (SLR). Projections of future melt rates are often derived from standalone ice sheet models, forced by data from global or regional climate models. In many cases, the surface mass balance parameterization relies on simplified schemes that relate melt with surface temperature.

In this study, we present a mass and energy conserving, 350-year simulation with the Community Earth System Model version 2.1 (CESM2.1) bidirectionally coupled to the Community Ice Sheet Model version 2.1 (CISM2.1). In this simulation, the carbon dioxide concentration is initially increasing by 1% per year  from pre-industrial levels (287 ppmv), to a quadrupling (1140 ppmv) and stabilization after year 140. The model simulates a global warming of 5.3 K and 8.5 K with respect to preindustrial by years 131-150 and 331-150, respectively, and a strong decline in the North Atlantic Meridional Overturning Circulation that is initiated before GrIS runoff substantially increases. 91% of the total GrIS contribution to global mean sea level rise (SLR, 1140 mm) is simulated in the two centuries following CO2 stabilization, as the mass loss increases from 2.2 mm SLR per year in 131-150 to 6.6 mm SLR per year in 331-351. This increase is caused by melt acceleration as the ablation areas expand, and Greenland summer surface temperatures predominantly approach melt conditions when the global warming exceeds a certain threshold (around 4.2 K).  This enhances the albedo and turbulent heat fluxes contribution to total melt energy.  

How to cite: Vizcaino, M., Muntjewerf, L., Sellevold, R., Ernani da Silva, C., Petrini, M., Thayer-Calder, K., Scherrenberg, M., Bradley, S., Fyke, J., Lipscomb, W., Lofverstrom, M., and Sacks, W.: Coupled ice-climate simulation of future Greenland ice sheet evolution: mechanisms, thresholds and feedbacks for accelerated mass loss, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19692, https://doi.org/10.5194/egusphere-egu2020-19692, 2020

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