This document is the seventh in a series of hazard-specific risk assessment modules, compiled as part of the Words into Action Guidelines on National Disaster Risk Assessment by UNISDR. This section provides a general introduction to the assessment of coastal erosion hazard and risk. Coastal erosion (or shoreline retreat) is the loss of coastal lands due to the net removal of sediments or bedrock from the shoreline. Erosion is typically driven by the action of waves and currents, and by mass wasting processes on slopes, and subsidence (particularly on muddy coasts). Significant episodes of coastal erosion are often associated with extreme weather events (coastal storms, storm surge and flooding) but also with tsunami.
A wide range of methodologies have been applied for coastal erosion hazard assessment. The key factors influencing these methodologies include the spatial and temporal scale of the analysis, the nature of the coastal landforms and the offshore environment in the area of interest, and the nature of the sea action being considered. This document also includes a case study of Australia and the inclusion of risk assessment into national DRR measures.