Rising seas could swallow up to 40 percent of Oahu's beaches by 2050

Rising sea levels may lead to the loss of 40 percent of all beaches on the island of Oahu, Hawaii, by the midpoint of this century, according to new research at the University of Hawaii at Manoa.

Unless beaches migrate landward, they will end up drowning due to sea level rise, according to the study. This will lead to widespread coastal erosion of private and public beachfront property along portions of the island, according to the University of Hawaii News report.

In addition, shoreline hardening, which is the construction of seawalls or revetments, interrupts natural beach migration, causing waves to erode the sand and accelerating coastal erosion on neighboring properties. This sets the stage for a beach to eventually drown in place as the ocean continues to rise.

The research team looked at the potential impacts to the most susceptible Oahu beaches by three different sea-level rise scenarios.

Key excerpt from the University of Hawaii report......

“We determined that almost 30 percent of all present-day sandy shoreline on OÊ»ahu is already hardened, with another 3.5 percent found to be so threatened that those areas qualify for an emergency permit today. Our modeling indicates that, as sea-level rises about 10 inches (0.25 meters) by mid-century, an additional nearly eight percent of sandy shoreline will be at risk of hardening—meaning at that point, nearly 40 percent of OÊ»ahu’s sandy beaches could be lost in favor of hardened shorelines," said Tiffany Anderson, who is a co-author of the study.