Sea-level rise (SLR) can amplify the episodic erosion from storms and drive chronic erosion on sandy shorelines, threatening many coastal communities. One of the major uncertainties in SLR projections is the potential rapid disintegration of large fractions of the Antarctic ice sheet (AIS). Quantifying this uncertainty is essential to support sound risk management of coastal areas, although it is neglected in many erosion impact assessments. Here, we use the island of Sint Maarten as a case study to evaluate the impact of AIS uncertainty for future coastal recession. We estimate SLR-induced coastal recession using a probabilistic framework and compare and contrast three cases of AIS dynamics within the range of plausible futures. Results indicate that projections of coastal recession are sensitive to local morphological factors and assumptions made on how AIS dynamics are incorporated into SLR projections and that underestimating the potential rapid mass loss from the AIS can lead to ill-informed coastal adaptation decisions.@en

To help decision makers in delta areas to select appropriate adaptation and mitigation strategies it is necessary to have a clear picture of the main drivers of risk and how risk evolves under changing conditions. Acknowledging these problems, the Delta Alliance and the TU Delft took the initiative to develop a new index that helps cities to better understand the dominant drivers of risk, formulate ambitions, and compare and share their results with other delta regions. The approach is based on previous work at TU Delft in collaboration with HKV and Deltares. The goal of this index is not to formulate an “exact” risk number, but aims to serve as a benchmark that supports communicating risk within the political arena and a peer-to-peer learning process with other deltas.@en