Abstract
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.
Highlights
Sea level change (SLC) will be one of the major impacts of climate change in the 21st century (Nicholls et al, 2011; Cazenave and Le Cozannet, 2014)
Most of the regional SLC projections have a higher median for the simulations where the contribution of ice sheet mass loss to SLC is considered to be asymmetric according to VW15
We have shown that the tail towards high values of SLC of the probability distribution of dynamical ice sheet mass loss highly influences the 90th, 95th and 97.5th percentiles of regional SLC
Summary
Sea level change (SLC) will be one of the major impacts of climate change in the 21st century (Nicholls et al, 2011; Cazenave and Le Cozannet, 2014). Including highend SLC projections is the logical step in coastal safety analysis, since coastal decision-making needs information on the upper boundary of possible future sea level when assessing future extreme events (De Winter and Ruessink, 2017). This requires two aspects: the transformation from global average SLC projections to regional SLC projections and the provision of insight of the uncertainties of these regional SLC. This emphasizes the need for regional SLC projections, since the amount of SLC can deviate from global average values due to changes in ocean currents, thermal expansion and gravitational and rotational effects induced by land ice and terrestrial ground
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
