Malama ai Hawai'i: 40% of O'Ahu Beaches Could Disappear by 2050

A study revealed that as sea levels rise, shoreline hardening on Hawaii beaches will also increase. Shoreline hardening causes beach loss; thus, if practices are not changed, we can expect as much as 40 percent beach loss in O'ahu by 2050. 

The study team suggests that existing legislation to manage beaches in Hawaii is not working, and the government needs to develop innovative programs to help beachfront owners and free the beach fronts to migrate towards land in the face of the inevitable sea-level rise. 

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The Beaches of O'ahu, Hawai'i

The study revealed areas and the severity of risks of shoreline hardening and beach loss. The study also revealed that nearly 40 percent of the beaches would be lost by the middle of the century. 

The study's computer model suggests that beach migration due to 9.8 inches of sea-level rise, the expected sea-level rise by midcentury will dramatically increase emergency applications for shoreline hardening. 

The findings also reveal that, currently, nearly 30 percent of O'ahu shorelines are already hardened. The study team also found around 3.5 percent of areas at significant risk that it needs to qualify and emergency permit the soonest.

As the sea level rise reaches 10 inches by 2050, nearly eight percent more sandy shorelines will have to be hardened. As this happens, almost 40 percent of Oahu's sandy beaches could be lost to hardened shorelines.

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Sea Level Rise and Shoreline Hardening 

As sea level rises, beaches tend to move landward else it would drown. The movement of the beach towards the land is called beach migration of shoreline retreat. This movement is causing erosion along with beach properties. 

In Hawaii, emergency protection for shoreline hardening or the construction of walls or revetments is granted on beach owners when evidence of beach erosion is within 6.1 m of a specific structure.

However, poor management of shoreline hardening has caused beach narrowing and loss around the globe. 

The shoreline hardening structures prevent beach migration, but the waves erode the sand, fast-tracking coastal erosion. As the sea level rises, the beach will eventually drown in place. 

In 2018, another study suggested that flanking, the accelerated erosion on properties, leads to shoreline hardening and condemns the entire beach.

Coastal Erosion 

As the sea-level rise, coastal erosion is inevitable. Sea level rise is expected to continue for several centuries, even if the greenhouse emissions are reduced or stopped.

Shoreline hardening continues as the preferred action to prevent coastal erosion on properties, Dr. Chip Fletcher, a study co-author said. Fletcher attributes this to management agencies unable to develop assisted transition plans for beachfront landowners impacted by the rapid sea-level rise. Beachfront lots are being sold to unsuspecting buyers with no regard for the welfare of the potential buyer.

Fletcher recommends that government agencies develop innovative and socially equitable programs to help beachfront owners and allow the sandy ecosystem to migrate landward naturally. 

According to Tavares, the lead author, beaches are vital ecosystems to flora and fauns. It offers protection from the storm, making Hawaii's economy due to the tourism industry it brings. This research suggests that dialogues on the beaches' future and how it will be managed and protected must be discussed soon.

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Check out more news and information on Sea Level Rise on Nature World News.