A state report on the impacts of sea level rise estimates that a 3.2-foot increase would displace 1,000 Hawaii Island residents and pose a serious flooding risk to urban areas of Hilo and Kona, in addition to resorts in Puako.
The 304-page Sea Level Rise Vulnerability & Adaptation Report was released Thursday and provides the first statewide assessment of impacts of rising seas as a result of climate change, according to the state Department of Land and Natural Resources.
Hawaii County Planning Director Michael Yee said the report should act as another wake-up call to the threats posed by climate change, though the tough planning decisions on mitigating its impact still lie ahead.
“We’re probably more reactive than proactive,” Yee said. “What’s great about this is it elevates the issue for us to talk.”
While rising seas are already a reality, sea levels globally are projected to rise by as much as 3.2 feet by 2100, according to the report, developed under DLNR’s Office of Conservation and Coastal Lands. The report notes that such an increase could happen even earlier and that Hawaii should start planning for that scenario now.
Statewide, the rise would render 25,800 acres of land unusable, displace about 20,000 people and cost $19 billion in lost property and structures, the report estimates.
For Hawaii Island, that means 1,000 people in need of new homes, based on current population levels, loss of 130 structures due to chronic flooding and an economic loss of $439 million due to the loss of structures and land. The report doesn’t estimate costs associated with relocating infrastructure or broader economic impacts.
Areas with the greatest potential economic loss include low-lying coastal areas from Puako to Kailua-Kona due to the high value of residential, commercial and resort lands. For instance, portions of the Hualalai Resort would be permanently flooded.
In Hilo, portions of coastal roads, such as Kalanianaole Avenue, would become chronically flooded. Harbors in Hilo and Kawaihae also would be impacted.
Kapoho, which already experiences coastal flooding, would see more properties claimed by the sea.
While Oahu would see the biggest economic impacts from climate change, the report notes Hawaii Island is seeing the largest rate of sea level rise at 2.95 millimeters a year, in part because of the island’s higher subsidence rate.
One of the report’s recommendations is to follow a “managed retreat strategy” for flooded areas to reduce impacts on agriculture and conservation lands.
Yee said the report was meant to be technical and not heavy on policy.
“There’s recommendations in terms of possible things that counties should look at,” he said. “When you talk about retreat and entire communities retreating back that’s obviously something that has to be really planned out.”
Yee said he emailed the report to other department heads Friday and noted that “nobody expects this to lessen in the near future.”
He said his department is in the process of updating the county’s General Plan. Planning for sea level increases could play a larger role.
“For us to ignore it certainly would be foolish,” Yee said. “No one wants to ignore it. In the General Plan, we’re trying to include an element of what’s happening around sea level rise.”
But he noted the county has many priorities that are unfunded and that the counties likely will be looking to the state for help or guidance.
“I’m taking a big guess at this, since the state played a big role (in the report) they are going to hopefully provide funding for each county to look at specifically what’s needed on each island,” Yee said.
To view the report, visit http://climateadaptation.hawaii.gov.
Email Tom Callis at tcallis@hawaiitribune-herald.com.