A study by a team of scientists, including researchers from the University of Hawaii at Manoa, has predicted that many low-lying atolls in the Pacific will become uninhabitable by the middle of the 21st century.

The study, which was published in ScienceAdvances today, factors in wave-driven flooding in its estimates of atoll habitability, in addition to sea level rise.

Using current greenhouse gas emission rates, the researchers — from the U.S. Geological Survey, National Oceanic and Atmospheric Administration, UH‘s International Pacific Research Center and others — improved estimates of atoll habitability by considering the effects of wave activity that flood low-lying islands with elevations of less than two meters.

Previous studies considered only the hazard from average sea level rise gradually inundating the atolls, and projected they would still be livable until 2100 or later. This study, however, included the additional effects of waves on Roi-Namur Island of Kwajalein Atoll in the Republic of the Marshall Islands.

The effects of waves have serious consequences far sooner, researchers said, which can lead to active flooding, the damage of coastal infrastructure and contamination of aquifers filled with freshwater. USGS geologist and lead author Curt Storlazzi predicted potable groundwater on the majority of atoll islands would be unavailable no later than the middle of the 21st century.

Researchers, including Hariharasubramanian Annamalai and Matthew Widlansky, formerly with IPRC and now with the UH Sea Level Center, evaluated 41 various global climate models that best simulated recent conditions and trends, such as precipitation and sea surface temperatures, in the Pacific and Indian ocean regions.

They then selected the five models that best captured past patterns and used them to project future conditions, particularly storm activity, for each decade until the year 2100.

“The worldwide teamwork is the beauty of this project, with all the different modeling aspects — climate, wave dynamics, groundwater hydrology — all brought together so smoothly and efficiently,” said Annamalai, who plans to study the Seychelles and Maldives next.