Rising sea levels accelerate; Hawaii remains vulnerable

 “The rate of global sea-level rise is telling us something about what to expect at most coastlines around the world.”

— Josh Willis, sea-level researcher at NASA’s Jet Propulsion Laboratory

Foreground

A NASA led Interagency Sea Level Rise taskforce recently provided up-to-date sea level rise findings and projections based on tidal gauge locations, including Hawaii, forecasting sea-level rise out and into the year 2050.

The report’s projections are based on data compiled in a recently released NOAA-led interagency report.  The study, published in Nature, combines data from 230 regional estimates and confirms that human-caused atmospheric warming is driving a rapid glacier retreat and corresponding sea level rise and expansion through rising global temperatures.

The report includes sea-level flood modeling and projected impacts to exposed coastlines with low-lying development, most specifically, the islands of Maui, Oʻahu, and Kauaʻi.

The study, however, failed to include sea-level rise impacts and associated flooding for the islands of Hawaii, Molokai, and Lānai, nor for some harbors or other back-bay areas throughout the state. Additional studies and funding would also be needed to include the annual high wave flooding for those areas previously omitted from the study.

Background

Since 2000, glaciers outside Greenland and Antarctica have lost about 270 billion tons of ice per year, a rate more than a third higher than in the previous decade.

The global glacier meltdown now underway feeds not only sea levels, but glaciers also serve as a freshwater reservoirs for millions of people, buffering against droughts and sustaining ecosystems. The glacier meltdown further threatens the disappearance of vital water supplies, increases sea level rise, and thereby the risk of coastal flooding.  Even small rises in sea level can displace millions, exacerbating climate migration and economic instability.

Scientists stress that the extent of future glacier loss hinges on global efforts to curb greenhouse gas emissions, and warn that a continuing rise in fossil fuel emissions will continue to push the world into unchartered territory – up to half of the world’s glacier ice will be lost by 50-75 years if the rate of global emissions continues to rise unabated. Policy makers who ignore the science, do so at everyones peril.

Long-term observational data from local tide gauge stations show sea level is rising and increasingly impacting Hawaii’s archipelago.

• Hawaii and other tropical Pacific sites will experience sea level rise that is 16% to 20% higher than the global average.
• Last Year, the world’s oceans rose 35% more than anticipated, with record-high temperatures driving the surge, according to a NASA-led study.  Global sea levels rose by 0.23 inches in 2024, exceeding the projected 0.17 inches, largely due to ocean warming.

While melting ice sheets have been the dominant factor over decades in rising sea levels, last year’s rise was driven mainly by thermal expansion, an increasing cause and effect phenomenon associated with rising global temperatures and tied to rising fossil fuel emissions.

Coastal cities, particularly in the U.S. Southeast, are experiencing even greater sea level increases, leading to more frequent flooding. Yet, Hawaii, an island state, is certainly not immune to effects of rising sea levels as the data already indicates.

Rising sea levels and warming oceans are reshaping coastlines placing millions at risk.

As glaciers and ice sheets melt and seawater expands due to rising temperatures, coastal cities face increasing threats from flooding, erosion, and extreme weather.

Warmer oceans are fueling stronger hurricanes, making storms more destructive and unpredictable.

The consequences are already visible

• Coral reefs, which support vast marine ecosystems, are experiencing widespread bleaching due to warming, disrupting fisheries and the livelihoods that depend on them.
• Scientists warn that some warming-driven changes may be irreversible within a human lifetime.
• And, as the oceans continue to absorb excess heat, the long-term implications on weather patterns, sea life, and global coastlines mean certain and established effects including  increasingly erratic and stronger storms couple to rising sea levels altogether point to a call to action – a remediation and solution-driven response, which is especially true for the residents of Hawaii, as well as the rest of the world.