For decades, sea level rise (SLR) has been framed as an accelerating threat to coastal communities, with alarming projections influencing land use policies and development plans. Recently, a state Department of Hawaiian Home Lands (DHHL) project at Ewa Beach fell victim to these dire projections. How so? By accepting a consultant’s “Desktop Study” that SLR will be so great that homes shouldn’t be built some two blocks away from the ocean.
Following the consultant’s report, 47 of DHHL’s 80 acres become unsuitable for houses, effectively eliminating 240 desperately needed homes for Native Hawaiians.
Various government agencies and a task force are cited by the consultant for its recommended SLR projection, but ground zero is an outdated computer model from a 2015 United Nations report. This model, called RCP 8.5, assumes an improbable fivefold increase in coal use and CO2 emissions through 2100 — a scenario most experts now consider implausible due to the global shift to natural gas, renewable energy and electric vehicles. Incredibly, the model used in the DHHL report surpasses even the RCP 8.5 projection. From 2000 to 2100, the model used by the consultant predicts SLR of 5 feet, 10 inches — nearly 6 feet!
NOAA tide data for Honolulu since 1905 tells a very different story (see NOAA, Relative Sea Level Trend, Honolulu, Hawaii). Over the past 120 years, SLR has followed a gradual, linear trend — not accelerating — of about 6/10ths of one inch per decade. In NOAA’s own words, “equivalent to a change of 0.51 feet in 100 years.” Yes, 6 inches per century. A similar linear trend has been observed in many other locations worldwide.
Over the past 25 years, SLR for Honolulu has been about 1.5 inches, far less than the projected 6.9-inch increase in the model used by the DHHL consultant. Over the next 25-year period the consultant’s projection assumes that SLR will rapidly accelerate to a whopping and unbelievable 13.8 inches higher than the current sea level. To date, the SLR data for Honolulu doesn’t support anywhere near such an extreme projection.
Many senior scientists from prestigious universities have expressed reservations about certain aspects of the climate change narrative and projections, asserting that the scientific evidence does not fully support them. While there is a broad consensus that CO2 contributes to climate change, significant disagreements exist regarding its magnitude, pace of change and impacts.
The DHHL project at Ewa Beach illustrates the practical consequences of relying on inflated SLR projections. Such projections reduce available homes, increase infrastructure and housing costs, and worsen the housing crisis.
So, where does this leave us? The reality is more complex than the alarming narrative of blaming SLR as the primary cause of beach erosion and loss of oceanfront structures. Other factors — occasional storm surges, construction on sand dunes at big-wave locales, and aging/inadequate foundations — have played significant roles. Addressing these factors with targeted adaptation is more practical and balanced than blanket restrictions on development.
Adaptation remains key. We should prepare for extreme weather events and storm surges, while continuing to monitor tide data closely. If the next decade shows rapid acceleration of SLR, we can adjust our policies accordingly. Until then, we should adopt flexible, data-driven strategies that allow development where appropriate and avoid unnecessary restrictions that hinder progress. And DHHL should undertake a “re-do” of the Ewa Beach project by an unbiased, objective consultant.
SLR is a long-term challenge requiring careful planning and decisions grounded in reality, not policies based on dire projections. While climate change is real, let’s focus on practical solutions and adaptation strategies that protect our communities and allow them to thrive. For the sake of future generations, we must prioritize facts over questionable conjecture.
Retired businessman Clint Churchill, left, and economist Bruce Plasch, Ph.D., represent the Practical Policy Institute of Hawaii.
