The Pacific’s most densely-populated island under threat

Published: 24 May 2018

A recent study has shown how damage to houses and infrastructures on Ebeye due to natural hazards and sea level rise may increase by a factor of three to four by the end of the century if no extra measures are taken. Given the fact that annual damage is already very extensive in the present situation, this may constitute a serious threat to the daily life of local inhabitants and the economies of the Marshall Islands and other low-lying island countries. The study was conducted in close collaboration between Dutch scientists from Deltares, the SISRI team from the Global Facility of Disaster Reduction and Recovery of the World Bank, the Joint Research Centre from the European Commission and the government of the Republic of Marshall Islands. The study was published in the Journal of Regional Environmental Change.

Flooding on the island of Ebeye during a daily, non-extreme, event

About Ebeye

The island of Ebeye is a small strip of land on the Kwajalein atoll (Republic of the Marshall Islands) in the middle of the Pacific Ocean. With a population density of about 40,000 inhabitants per km2, it is the most densely-populated island in the Pacific and the sixth in the world. It has an average height of about 2 m above mean sea level and so it is highly vulnerable to natural hazards and climate change.  A large proportion of the population currently works at the nearby American base on Kwajalein Island. Over half of the population is under 20 years old.

Natural hazards, climate change and induced damage

The scientists have assessed how annual damage to the island induced by coastal hazards and climate change will increase during this century. ‘Annual damage to property and infrastructure may increase on Ebeye by a factor of three to four by the end of the century according to standard RCP scenarios for sea level rise,’ says Alessio Giardino, a coastal engineer and disaster risk specialist at Deltares. Simulations were carried out at Deltares using a state-of-the-art modelling train that included the assessment of offshore hazards, an assessment of the impact on property and the population on the islands, and the presentation of the results as risk maps and cost-benefit analyses, all for a range of climate change scenarios. ‘Quantitative risk-based information is extremely useful to help increase resilience and improve planning for small islands. This study informed the preparation of a US$49 million resilience project funded by the World Bank and the Green Climate Fund,’ says Denis Jean-Jacques Jordy, lead environmental specialist at the World Bank. The results can also serve as a proxy for many other islands in similar situations.

Predicted development of expected annual damage ($/m2) on Ebeye for different time slices (Giardino et al., 2018)

Climate Change Scenarios

Capping the temperature increase at 2°C as required by the Paris Agreement will reduce the consequences slightly but that will not be sufficient. Furthermore, a temperature increase on this range will lead to additional irremediable damage to the coastal ecosystems and most of the scenarios indicate that this limit will already be exceeded in no more than fifty years from now. Sea level rise is also a phenomenon with a certain time lag in relation to increases in temperature, rendering the pathway to warming an important parameter and implying that slower warming will result in additional sea level rise for a given temperature. This consideration is generally forgotten in the public debate.

Possibilities for risk reduction, mitigation and adaptation

Measures for reducing disaster risks can be useful in terms of mitigating risks and expected damage in current and future scenarios. However, they should be incorporated in a long-term adaptive planning strategy for these islands. The effectiveness of adaptation options will be limited in time depending on the design and the future rate of sea level rise. Most solutions will serve to ‘buy time’ until a new solution is found. Adopting long-term adaptation strategies will therefore ensure that the effectiveness and impact of investments and solutions will be maximised, which also produces direct benefits for the local people.

Full article

The full article, “Coastal hazard risk assessment for small islands: assessing the impact of climate change and disaster reduction measures on Ebeye (Marshall Islands)” is available online.