Accelerating sea level rise brought on by climate change poses significant challenges to Hawaii’s shorelines, according to geologists who have been studying the state’s coastlines for decades, including SOEST earth sciences professor and associate dean Chip Fletcher.
The state recently commissioned a project to assess the feasibility and implication of managed retreat by looking at how other regions have successfully moved from coastlines. And the biggest takeaway: Managed retreat is a difficult but necessary option to consider.
“Managed retreat is the idea that we move our communities out of the way because sea level is rising,” said Fletcher.
Building on eroding coasts increases vulnerability to these hazards, but finding a solution that everyone agrees on is much more challenging. The concept of managed retreat is simple, yet making it happen is anything but.
Managed retreat essentially means shifting development inland from the coast either through the physical movement of structures or through legislation or policy that changes the restrictions and management of Hawaii’s shorelines.
Shoreline erosion affects tourist areas such as Waikiki, Honolulu’s urban core, and rural coastal homes, many of them owned by middle-class families who have lived on the coast for generations.
Managed retreat is an individualized approach that takes into consideration the coastline’s current conditions and existing hazards or impending threats. In some situations it could mean not only physically relocating existing buildings or shifting the placement of infrastructure, but also creating new regulations that restrict future development of vulnerable areas.
Ultimately, what the Office of Planning Coastal Zone Management Program determined in its report was that it is “currently not possible to develop a step-by-step plan to implement managed retreat for areas in Hawaii threatened by sea level rise and/or other coastal hazards given the various unknowns and competing priorities identified throughout the course of the assessment.”