Climate adaptation of coastal structures

Projections of sea level rise (SLR) vary in time and go together with large uncertainties. Not only best estimates of SLR vary in time, also the estimated uncertainties in SLR vary in time. Not all processes that cause the SLR are fully understood, which is illustrated by recent studies that discuss the rapid Antarctic ice sheet mass loss with a possibility of a much faster SLR than expected before. With rapid SLR significant changes in the hydraulic loading on coastal structures can occur within the lifetime of coastal structures. Since important changes, but with an unknown magnitude, can occur within the lifetime of coastal structures it is wise to anticipate for potential future adaptations, rather than ignoring potential future threats (leading to unsafe situations or high adaptation costs) or constructing coastal structures for the worst-case scenario (leading to un-economical designs). This paper illustrates a method to select adaptation measures for coastal structures for an uncertain future SLR. In addition, knowledge gaps that are relevant for the assessment of the optimal adaptation pathways are identified.