People who live on low-lying atolls in the Pacific like Roi-Namur in the Republic of the Marshall Islands may have to evacuate due to rising sea level in as little as 12 years, according to a new study by researchers from the USGS, NOAA and the University of Hawai‘i’s International Pacific Research Center.
Sea levels are rising, with the highest rates in the tropics, where thousands of low-lying coral atoll islands are located. Most studies on the resilience of these islands to sea-level rise have projected that they will experience minimal inundation impacts until at least the end of the 21st century. However, these have not taken into account the additional hazard of wave-driven overwash or its impact on freshwater availability. We project the impact of sea-level rise and wave-driven flooding on atoll infrastructure and freshwater availability under a variety of climate change scenarios. We show that, on the basis of current greenhouse gas emission rates, the nonlinear interactions between sea-level rise and wave dynamics over reefs will lead to the annual wave-driven overwash of most atoll islands by the mid-21st century. This annual flooding will result in the islands becoming uninhabitable because of frequent damage to infrastructure and the inability of their freshwater aquifers to recover between overwash events. This study provides critical information for understanding the timing and magnitude of climate change impacts on atoll islands that will result in significant, unavoidable geopolitical issues if it becomes necessary to abandon and relocate low-lying island states.
An April 25 news release from the University of Hawai‘i puts the timetable for evacuation in even more dire terms: “The combination of rising sea levels and wave-driven flooding will cause frequent damage to infrastructure and will irreversibly contaminate island freshwater resources by 2030-2060,” it states.
“The tipping point when potable groundwater on the majority of atoll islands will be unavailable is projected to be reached no later than the middle of the 21st century,” said Curt Storlazzi, USGS geologist and lead author of the new report, in the news release.
What’s more, Storlazzi said that these results are applicable to low-lying islands around the world. And Hariharasubramanian Annamalai of the UH Sea Level Center intends to expand on this research by looking at the Seychelles and the Maldives in the Indian Ocean. There, increased cyclone activity is already impacting residents.
Photo of Kwajalein Atoll: NASA/Wikimedia Commons
Sea Level Rise Inundation imagery courtesy University of Hawai‘i