Study: 40% of Hawaii’s beaches could disappear in 30 years due to sea level rise

HONOLULU, Hawaii (HawaiiNewsNow) - A new study by published out of the University of Hawaii predicts that as much as 40% of Hawaii’s beaches could be lost by the year 2050 because of sea level rise.

The research was conducted by the School of Ocean and Earth Sciences at UH and also looks at beach hardening, which is the practice of building groins and sea walls to unnaturally maintain beaches.

A previous study by the group explains how sea walls can actually accelerate erosion and predicts a grim future where close to 25 miles of beaches on Oahu could disappear if practices don’t change.

The study also points out that sea level rise is speeding up — estimating that it could raise by nearly 10 inches in the next 30 years. Researchers suggest that if we continue the practice of beach hardening — building sea walls to retain shorelines — the outlook isn’t good.

They identified the location and severity of risk of shoreline hardening and beach loss, and a potential timeline for the increase in erosion hazards.

The most threatened properties fall into an “administrative erosion hazard zone,” an area likely to experience erosion hazards and qualify for the emergency permitting process to harden the shoreline.

“By assessing computer models of the beach migration caused by 9.8 inches of sea-level rise, an amount with a high probability of occurring before mid-century, we found that emergency permit applications for shoreline hardening to protect beachfront property will substantially increase,” said graduate researcher Kammie Tavares in SOEST’s Department of Earth Sciences.

They want a government program to help transition shoreline property owners out of their doomed locations and develop a long-term plan to stay out of the way of natural beach migration.

“Beaches are critical ecosystems to native plants and animals, offer protection from storms, are an essential cultural setting, and attract tourists, who are important for Hawaii’s current economy,” added Tavares. “This research shows that conversations on the future of our beaches and how we will care for them must happen now rather than later, if we are to protect our sandy beaches.”

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