Hawaii Sea Level Rise Vulnerability and Adaptation Report

Hawaii’s Sea Level Rise Vulnerability and Adaptation Report was initially mandated by the Hawaii Climate Change Adaptation Initiative (Act 83, 2014, and expanded by Act 32, 2017). This report represents the first state-wide vulnerability assessment for sea level rise (SLR) coastal hazards in Hawaii.  Statewide and island specific adaptation recommendations are given to help reduce Hawaii’s exposure to sea level rise and increase coastal hazard resilience.

Vulnerability was assessed for land use, people, property, cultural and natural resources, and critical infrastructure exposure to impacts for each island in the state (Hawai’i, Kaua’i, Lana’i, Oahu, Maui, Moloka’i, and the Northwestern Hawaiian islands). Sea level rise vulnerability was modeled based on passive flooding, annual high wave flooding, and coastal erosion in the SLR exposure area. Vulnerability to 1.1 feet of sea level rise in the SLR exposure area is used to approximate current or near-term exposure to coastal hazards and sea level rise; and a 3.2 feet of sea level rise was chosen to determine hazards that may occur in the mid to latter half of this century.

The assessment found that chronic flooding in the area with 3.2 feet of SLR would render over 25,800 acres of land in the State unusable. The impacts were monetized, and the value of projected flooded structures combined with the land value of the 25,800 acres, is estimated to over $19 billion in economic loss by 2050. Hawaii’s urban areas are the most vulnerable economically, with the greatest potential loss in Honolulu at 66% of the total statewide economic loss projected, due to the density and economic assets potentially exposed to SLR. The report states that the impacts of sea level rise on O‘ahu could then generate substantial social, infrastructure, and economic impacts with ripple effects throughout the State. 

Policy recommendations and supporting recommended actions are extensively detailed in the report - developed as guidance for state and local agencies, communities, and stakeholders.

Recommendation 1: Support sustainable and resilient land use and community development

Recommendation 2: Prioritize smart urban redevelopment outside the SLR exposure area and limit exposure within the area

Recommendation 3: Incentivize improved flood risk management

(through support to a state-wide Community Rating System program, encouraging property owners outside currently regulated flood zones to purchase flood insurance, and incorporate sea level rise in hazard mitigation plan updates and disaster recovery frameworks.)

Recommendation 4: Enable legacy beaches to persist with SLR

Recommendation 5: Preserve Native Hawaiian culture and communities with SLR

Recommendation 6: Protect nearshore water quality from SLR impacts

(by initiating a comprehensive review of environmental regulations that allow for the siting of environmental hazards, such as hazardous materials/waste storage facilities and onsite wastewater storage systems in SLR zones)

Recommendation 7: Develop innovative and sustainable financing and incentives to support adaptation to SLR

Recommendation 8: Support research, assessment, and monitoring to support adaptation to SLR

Recommendation 9: Promote collaboration and accountability for adapting to SLR

 

Publication Date: December 29, 2017

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  • Assessment
  • Policy analysis/recommendations

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