Assessing Social Impact of Storm Surge and Sea Level Rise Compound Effects in Viti Levu, Fiji, Comparing With The Historical TC Records

Abstract

 The compounding effects of storm surges and sea level rise (SLR) are expected to accelerate coastal hazards and inundation. Therefore, projecting the compound effects in coastal territories is important for impact assessments and adaptation. Small island states in the South Pacific are one of the areas that are the most highly impacted by climate change. Storm surges are caused mostly by tropical cyclones (TCs), which may result in a significant portion of the population being temporarily displaced by infrastructure damage, flooding and erosion. Meanwhile, SLR is changing coastlines permanently and may result in a lasting displacement of the exposed population. This study focuses on Viti Levu, the largest and most populous island in Fiji, and estimates the impact of SLR and storm surge on the coasts and population, by using data from observations and future projections to estimate the angle of approach, occurrence frequency, and intensity of TCs. Based on the findings of this study it can be inferred that while Fiji has had a long record of TCs that hit its islands, SLR may become a more significant phenomenon that shapes climate-related migration. While a milder increase in the climate radiative forcing (+2K scenario) will increase the exposed population less dramatically compared with a sharper increase (+4K scenario), we conclude that either scenario would result in a significantly higher number of the population exposed during future storms.