Maui County leaders heard detailed modeling and local projections at the Agriculture, Diversification, Environment and Public Transportation (ADEPT) Committee meeting on Oct. 9 showing accelerating sea level rise, hotter ocean temperatures and shifting rainfall patterns that will increase coastal flooding, groundwater inundation and erosion along island shorelines.

"Climate change is real. It is here and its impacts will get worse," Committee Chair Gabe Johnson said in opening remarks, framing the presentations the committee received from academic and nonprofit experts.

The presentation by Charles "Chip" Fletcher, dean of the School of Ocean and Earth Science and Technology at the University of Hawai‘i at Mānoa, showed multiple pathways of sea level and coastal flood risk, including models of storm-drain backflow, groundwater inundation and seasonal wave overtopping. "Sea level rise is unstoppable from a human time frame," Fletcher said, adding that satellite records show the rate of sea level rise has doubled in 30 years and that two feet of sea level rise — a projection he cited for as early as 2060 — would render many storm-drain outfalls unusable during high tide in places such as Waikiki.

Why this matters: County officials and presenters said the combination of higher seas, increased ocean heat and more variable rainfall will compound hazards already familiar to island communities — flooded roads, saltwater intrusion into groundwater, coral bleaching and vegetation shifts that feed wildfires. Tonya Graham of the GEOS Institute and Darla Palmer Ellingson of 360 Green Living tied those physical risks to community impacts: risks to food access, beach loss, disruption of infrastructure and damage to tourism and small businesses.

Most important evidence and local details: Fletcher presented global drivers (ocean thermal expansion, melting ice, and continental groundwater losses) and then focused on Hawaii-specific trends. He said Hawaii’s ocean temperatures have risen strongly in recent decades and that Maui County has seen average temperature increases and reduced trade-wind days. Presenters reported regional precipitation declines: Maui Island precipitation down about 20% since 1920, Molokai about 24% and Lāna‘i about 26% (presenters). Fletcher also said the area burned by wildfire in Maui County has quadrupled since 1950.

Presenters described a range of adaptation responses and trade-offs. Fletcher warned that hard coastal armoring kills beaches when it prevents shoreline migration: "If you respond to coastal erosion by protecting the land with seawalls, you will kill the beach," he said, noting a state-level restriction on shoreline armoring enacted in 2020 that limits using seawalls as a long-term strategy. He and others identified alternative approaches that can be combined: elevating structures (post-and-pier), strategic relocation of vulnerable coastal roads (the state has identified segments of Honoapiʻilani Highway for realignment), managed sand nourishment where appropriate as short-term maintenance, and planning for eventual retreat of development from the most exposed shorelines.

Speakers and county staff emphasized co-benefits when feasible: raising coastal buildings can reduce heat exposure, improve storm resilience and allow wave overwash to pass beneath structures rather than destroy them. Fletcher urged taking a long-term view when investing in infrastructure: "Any infrastructure that you're looking to have last for a long period of time needs to really take into account that longer term trajectory," he told the committee.

County response and next steps: Department of Environmental Management (DEM) staff — including Deputy Director Michael Peterson and Cecile Powell, manager of the Environmental Protection and Sustainability Division — said the department is building staff capacity and plans a consultant-assisted update to the county Climate Action and Resiliency Plan (CARP). DEM said it is working on a public-facing CARP dashboard to track strategies and that county departments will collaborate with community partners. Committee members directed staff to continue coordination; the committee ultimately deferred the informational item for follow-up.

Ending: Committee members and presenters said the pace of sea-level and climate impacts argues for accelerated planning and funding. Fletcher recommended prioritizing infrastructure investments that yield multiple benefits and planning retreat and shoreline management with transparency and community engagement. The committee asked departments to provide follow-up materials and said they will continue the item at a later meeting.