Maximum elevation above water: + 2.12m
Land area: 1.7 ha
Reef flat area: 83 ha
Population (2015): 529
Households (2015): 108
Households with income below poverty threshold (2015): 73%
Median height of tidal flooding (2016): + 24.5cm
Number of flooded days per year (2016): 44 days
Bilangbilangan is located the furthest from the mainland (compared to Ubay, Pangapasan and Batasan). Its white sand beaches are picturesque, although they are slowly eroding because of poorly constructed seawalls lining the perimeter of the island. Being relatively remote and, at the same time, having a small reef flat area, Bilangbilangan is highly susceptible to the effects of high waves. Unfortunately, its small reef flat is not conducive for growing mangroves, reducing the range of ecosystem-based adaptation options. Nonetheless, Bilangbilangan has a well-managed marine protected area, with many patches of large, hard coral stones scattered throughout its reef flat.
The experience of Bilangbilangan underscores the need to examine the unique geophysical characteristics of each island, in order to identify the risks to which it is exposed and, more importantly, to be able to take advantage of its natural ability to adapt. A recent study examining 12 different atolls in central and western Pacific over the past few decades (when the region experienced sea level rise up to 3 to 4 times faster than the global average) found very little evidence of heightened erosion and reduction in island size (McLean and Kench, 2015), indicating how they are persisting rather than sinking in the face of sea level rise – as otherwise suggested by popular narratives about “disappearing islands”. Coral islands exist in very dynamic environments, often changing in shape and position within the reef surfaces as a result of seasonal shifts in wave processes and extreme events (Kench and Brander, 2006) and sea level change (Webb and Kench 2010). In other words, islands have a natural ability to adapt to environmental changes, and harnessing this natural ability could be a potential option for adaptation.
Kench, P.S., Brander, R.W., 2006. Response of reef island shorelines to seasonal climate oscillations: South Maalhosmadulu atoll, Maldives. Journal of Geophysical Research 111, F01001. doi:10.1029/2005JF000323.
McLean, R. and Kench, P., 2015. Destruction or persistence of coral atoll islands in the face of 20th and 21st century sea‐level rise?. Wiley Interdisciplinary Reviews: Climate Change, 6(5), pp.445-463.
Webb, A.P. and Kench, P.S., 2010. The dynamic response of reef islands to sea-level rise: evidence from multi-decadal analysis of island change in the Central Pacific. Global and Planetary Change, 72(3), pp.234-246.