Only two of the sites (Nuatambu and Mararo) are populated, whilst the sites in Isabel and Roviana have no known history of continuous human habitation. (a) Map of the Solomon Islands relative to south Pacific region indicating study sites (•) in Choiseul (Nuatambu), Malaita (Mararo) and Isabel Provinces, (b) inset of study sites across northern Isabel. Summary data of island area and percentage decadal change at seven atoll sites in the Central Pacific (modified from Mc Lean and Kench 2015) and Solomon Islands (this study).
The islands in Roviana are used on a daily basis by nearby communities for fishing, whilst the islands in Isabel are infrequently visited on a weekly-monthly basis by fishers with no significant disturbance of coastal vegetation by fishers observed. Island-change data within the highlighted ±3.0% band width is not considered significant.
The higher local rate of historical rise is the result of both a larger global averaged rate of sea-level rise (Church and White 2011) and also stronger trade winds since 1990 (Merrifield and Maltrud 2011) which are directly related to the decreasing Pacific Decadal Oscillation index (Zhang and Church 2012).
These PDO and ENSO conditions may ease in the Solomon Islands in coming decades to produce sea-level rise rates closer to the global average.
The volcanic islands of Melanesia are typically considered to be less vulnerable to sea-level rise due to high elevations and low population densities (Barnett and Adger 2003, Nunn making it amongst the most sparsely populated of Pacific Island nations. Understanding the drivers of this rapid shoreline recession and contrasting erosion rates between different areas within this region is critical to provide a foundation for local adaptation strategies.