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Island Stability on the Takapoto Atoll, French Polynesia

Paper Reviewed
Duvat, V.K.E. and Pillet, V. 2017. Shoreline changes in reef islands of the Central Pacific: Takapoto Atoll, Norther Tuamotu, French Polynesia. Geomorphology 282: 96-118.

Atoll islands are considered by many to be especially vulnerable to climate-related changes (rising seas, storms and ocean acidification) due to their small size and low elevation. However, more and more research has revealed that small oceanic islands are much more resilient to the forces of both nature and humanity than originally thought (see, for example, multiple recent studies on this subject posted here). The latest such study to illustrate their resilience to climate change comes from Duvat and Pillet (2017).

By examining multi-date aerial imagery, the two French researchers set out to assess shoreline and island changes on Takapoto Atoll, Northern Tuamotu, French Polynesia, between the years 1969 and 2013. Takapoto is a closed atoll with no pass connecting the open ocean to the lagoon. It is orientated northeast to southwest with dimensions of approximately 20 by 6.5 km and the total land mass within the atoll in 2013 consisted of 43 islands (~13 km2). However, limitations in the spatial extent of the aerial imagery utilized to determine shoreline position restricted their analysis to only 27 of the 43 islands. And how did those islands change over the 44-year period of analysis?

According to Duvat and Pillet, over the 44-year period most of the reef islands "exhibited either areal stability (41%) or expansion (33%)," including the two largest islands (772 ha and 320 ha), which showed expansion and stability, respectively. In commenting on these findings, the two researchers say "our results therefore confirm that the reef islands of the northern Tuamotu chain are robust landforms showing no sign of widespread erosion or of positional instability as a result of contemporary sea-level rise." Consequently, we have another example where a climate model claim (submersion of low-lying islands due to warming climate and rising seas) is failing to materialize out in the real world.

Posted 27 June 2017