In addition to the Army's Ronald Reagan Ballistic Missile Defense Test Site where 1,300 people work, over 50,000 people call the Marshall Islands home.

A recently completed SERDP project provides a new understanding as well as specific information on the impact of climate change and sea-level rise on Roi-Namur Island on Kwajalein Atoll in the Republic of the Marshall Islands.  Results include an improved and updated timeline of the threats that low-lying atoll islands face due to future climate change. Researchers on this effort included the U.S. Geological Survey, National Oceanographic and Atmospheric Administration, Deltares, and University of Hawaii. To produce the study, they relied on physics-based numerical oceanographic and hydrogeologic models to project the effects of wave-driven flooding of the island and evaluate its resulting impacts to infrastructure and freshwater resources.

The impact of sea-level rise inundation combined with annual wave-driven flooding will begin to significantly negatively impact Roi-Namur when mean sea level is 0.4 meters higher than at present.

Without active management measures the annual amount of seawater flooded onto the island during storms will be of sufficient volume to make the groundwater nonpotable year-round.

Additionally, at 0.4 meters of sea-level rise, much of the isthmus that connects Roi and Namur will be flooded annually, negatively impacting the facilities in those locations.

Proposed next steps for this research are detailed in the Final Report but one recommendation is to comprehensively identify DoD managed atoll islands most vulnerable to sea-level rise and associated impacts over the next 20 to 50 years. Managers could then prioritize funding for further place-based studies and/or restoration and adaptation efforts based on those locations. This critical work has been featured through several media outlets, including, Science Advances, Frontline PBS, and Scientific American to name a few.