A Review on Multidecadal Coastal Changes at Funafuti, Tuvalu from 1897 to 2015

Abstract

Tuvalu is a small reef islands country in the Pacific Ocean. Its coastal regions are very much dynamicdue to the profound effects of tropical cyclones and sea level rise (SLR). However, research works on coastlinedynamics of Tuvalu mainly cover its capital, Funafuti. Therefore, this review summarizes the extent of long-term coastal changes in different islets of Funafuti and on overall Tuvalu. In Funafuti, highly accreting areas areTe Afualiku, Fuafatu, Motugie, and Amatuku, and highly eroding areas are Fuagea and Tefala with the fullydisappeared islet of Vasafua after 2005. However, in spite of different causes and supposition of scientists ondisappearing these lands the accretion is more dominant than erosion which resulted in 7.3% net increase of landareas of Tuvalu over 117 years till 2015. Severe tropical cyclones mainly caused accretion of land areas byforming coral rubble rampart formation and further reworks and erosion to small sandy islands whereas frequentlow-energy cyclones mainly caused erosion. Though, till now severe erosion of coastal areas are not evident byglobal SLR, islets of Funafuti experienced remarkable shoreline increase as formation of 30–40 m wide rubblerampart formation along 19 km in 1971 by tropical cyclone Bebe and net increase of area of 3.45 ha by tropicalcyclone Pam in 2015. In spite of such overall accretion of coastal areas several scientists suspect drowning of itsareas in future because of high SLR (~5.1±0.7 mm/year) at Funafuti which supposedly will not work as abreakwater anymore. Thus, protection measures should be taken to prevent coastline erosion as well as landreclamation activities should be done following the global examples.