EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Clouds increase uncertainty in surface melt projections over the Antarctic ice shelves

Christoph Kittel1,2, Charles Amory2, Stefan Hofer3, Cécile Agosta4, Nicolas C. Jourdain2, Ella Gilbert5, Louis Le Toumelin6, Etienne Vignon7, Hubert Gallée2, and Xavier Fettweis1
Christoph Kittel et al.
  • 1University of Liège, Laboratory of climatology, Department of Geography, Liège, Belgium
  • 2Univ. Grenoble Alpes/CNRS/IRD/G-INP, IGE, Grenoble, France
  • 3Department of Geosciences, University of Oslo, Oslo, Norway
  • 4Laboratoire des Sciences du Climat et de l'Environnement, LSCE-IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France}
  • 5Department of Meteorology, University of Reading, Whiteknights Rd, Reading, United Kingdom
  • 6Univ. Grenoble Alpes, Université de Toulouse, Météo-France, CNRS, CNRM, Centre d’Études de la Neige, Grenoble, France
  • 7Laboratoire de Météorologie Dynamique/IPSL/Sorbone Université/CNRS, UMR 8539, Paris, France

Recent warm atmospheric conditions have damaged the ice shelves of the Antarctic Peninsula through surface melt and hydrofracturing, and could potentially initiate future collapse of other Antarctic ice shelves. However, model projections with similar greenhouse gas scenarios suggest large differences in cumulative 21st century surface melting. So far it remains unclear whether these differences are due to variations in warming rates in individual models, or whether local surface energy budget feedbacks could also play a notable role. Here we use the polar-oriented regional climate model MAR to study the physical mechanisms that will control future surface melt over the Antarctic ice shelves in high-emission scenarios RCP8.5 and SSP585. We show that clouds enhance future surface melt by increasing the atmospheric emissivity and longwave radiation towards the surface. Furthermore, we highlight that differences in meltwater production for the same climate warming rate depend on cloud properties and particularly cloud phase. Clouds containing a larger amount of liquid water lead to stronger melt, subsequently favouring the absorption of solar radiation due to the snow-melt-albedo feedback. Since liquid-containing clouds are projected to increase the melt spread associated with a given warming rate, they could be a major source of uncertainties related to the future Antarctic contribution to sea level rise.

How to cite: Kittel, C., Amory, C., Hofer, S., Agosta, C., Jourdain, N. C., Gilbert, E., Le Toumelin, L., Vignon, E., Gallée, H., and Fettweis, X.: Clouds increase uncertainty in surface melt projections over the Antarctic ice shelves, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2873,, 2022.