Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 17, 2125-2141, 2017
https://doi.org/10.5194/nhess-17-2125-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
04 Dec 2017
Impact of asymmetric uncertainties in ice sheet dynamics on regional sea level projections
Renske C. de Winter1, Thomas J. Reerink2, Aimée B. A. Slangen3, Hylke de Vries4, Tamsin Edwards5, and Roderik S. W. van de Wal2 1Institute for Marine and Atmospheric research Utrecht, Physical Geography, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, the Netherlands
2Institute for Marine and Atmospheric research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, the Netherlands
3NIOZ Royal Institute for Sea Research, Department of Estuarine and Delta Systems, and Utrecht University, Korringaweg 7, 4401 NT Yerseke, the Netherlands
4Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, 3730 AE De Bilt, the Netherlands
5Open University, Milton Keynes, UK
Abstract. Currently a paradigm shift is made from global averaged to spatially variable sea level change (SLC) projections. Traditionally, the contribution from ice sheet mass loss to SLC is considered to be symmetrically distributed. However, several assessments suggest that the probability distribution of dynamical ice sheet mass loss is asymmetrically distributed towards higher SLC values. Here we show how asymmetric probability distributions of dynamical ice sheet mass loss impact the high-end uncertainties of regional SLC projections across the globe. For this purpose we use distributions of dynamical ice sheet mass loss presented by Church et al. (2013), De Vries and Van de Wal (2015) and Ritz et al. (2015). The global average median can be 0.18 m higher compared to symmetric distributions based on IPCC-AR5, but the change in the global average 95th percentile SLC is considerably larger with a shift of 0.32 m. Locally the 90th, 95th and 97.5th SLC percentiles exceed +1.4, +1.6 and +1.8 m. The high-end percentiles of SLC projections are highly sensitive to the precise shape of the probability distributions of dynamical ice sheet mass loss. The shift towards higher values is of importance for coastal safety strategies as they are based on the high-end percentiles of projections.

Citation: de Winter, R. C., Reerink, T. J., Slangen, A. B. A., de Vries, H., Edwards, T., and van de Wal, R. S. W.: Impact of asymmetric uncertainties in ice sheet dynamics on regional sea level projections, Nat. Hazards Earth Syst. Sci., 17, 2125-2141, https://doi.org/10.5194/nhess-17-2125-2017, 2017.
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Short summary
This paper provides a full range of possible future sea levels on a regional scale, since it includes extreme, but possible, contributions to sea level change from dynamical mass loss from the Greenland and Antarctica ice sheets. In contrast to the symmetric distribution used in the IPCC report, it is found that an asymmetric distribution toward high sea level change values locally can increase the mean sea level by 1.8 m this century.
This paper provides a full range of possible future sea levels on a regional scale, since it...
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