34% of Hawai‘i’s coast at risk as climate change accelerates, study finds

High-risk zones for coastal damage on O‘ahu include the North Shore from Haleiwa to Kahuku, which is exposed to high wave energy, and Ewa Beach, which has low elevation, little reef protection or natural habitat and greater vulnerability to sea level rise. Other areas at risk on Oahu include stretches of Kailua, Waimanalo and Waianae. At left, erosion eats away at the coastline at Sunset Beach on the North Shore. Image courtesy of Dennis Oda/Honolulu Star-Adverstiser.

A study by University of Hawai‘i researchers has found a third of the state’s shorelines are vulnerable to coastal hazards as the waves and storms that hit the islands become intensified by the growing impacts of sea level rise.

Published in the journal Ocean and Coastal Management, the study examined the shorelines of seven of the eight main Hawaii islands and determined their vulnerability to coastal hazards, ranking each area from low to high risk. Researchers found that 34 percent of Hawai‘i is moderately to highly vulnerable, with shores on Maui, O‘ahu, and Kaua‘i at highest risk.

High-risk zones on O‘ahu include the North Shore from Hale‘iwa to Kahuku, which is exposed to high wave energy, and Ewa Beach, which has low elevation, little reef protection or natural habitat and greater vulnerability to sea level rise. Other areas at risk on O‘ahu include stretches of Kailua, Waimānalo, and Wai‘anae.

Primary author Yaprak Onat from the Department of Ocean Resources and Engineering (ORE) accounted for a range of factors in determining coastal hazard exposure, including topography, underwater landscape, erosion, wave energy, vulnerability to surge and sea level rise. Onat also factored in the effects of natural coastal habitats, defensive structures like sea walls and revetments, plus human activities.

Read more about it in the Honolulu Star-Advertiser and Hawaii News Now.

Related: Listen to an interview with coastal geologist and UH Sea Grant extension agent Dolan Eversole about managing our coastal resources as we face rising warming waters on Hawaii Public Radio.