2019-09-25 Meeting Minutes (EMC)

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Dr. Romine introduced himself. He is with the University of Hawaiʻi Sea Grant College Program and is a coastal geologist by training and background. He works out of UH-Mānoa and has worked on coastal processes, beach erosion, and human impacts on the shoreline. He works closely with the Department of Land and Natural Resources and actually worked there for six years. At Mānoa his focus is on longer range projects, such as climate adaptation initiatives, and he is involved with the Climate Change Mitigation and Adaptation Commission. Dr. Romine did a slide presentation entitled “Sea Level Rise Observations and Outlook for Hawaiʻi Island.” A few of the highlights: • The sea level at Hilo Bay has been increasing roughly 3 mm per year, which comes to about 12 inches over a century. • The rate of global mean sea level rise is increasing and has roughly doubled from .6 mm per year in the early part of the century to 3.2 mm. Hilo’s rate is similar to the global rate but somewhat higher due to the weight of the volcanoes pushing into the earth’s crust. • There are two contributors to the sea level rise: added water from melting glaciers and ice sheets, and thermal expansion. • Sea surface temperatures are increasing and contributing to the sea level rise. • There are satellite missions that circle around the earth repeatedly, taking measurements of ice mass changes. • Greenland and the Antarctic ice mass are the two ice sheets of most concern. Greenland is losing about 300 billion tons of ice per year, and Antarctica is losing about 125 billion tons per year. • Projections: it is very likely the sea level will rise 0.5 to 1.2 feet by 2050 and 1.0 to 4.3 feet by 2100, and extremely likely it will continue beyond 2100. • The rise being experienced now is mainly from the past couple of decades’ worth of greenhouse gas emissions, and projections show it will only continue to rise. • NOAA forecasts a 1-foot rise by 2050 and 3-foot rise by 2100. • King tide events will occur more frequently and severely. • There are projections the ice mass loss may change the gravity field and possibly the rotation of the planet. • Scenario planning—how planners plan and engineers design, given the range of possible scenarios—is ongoing. Higher scenarios should be considered for a major CIP investment such as a wastewater treatment plant or power generation facility. • Hawaiʻi became the ﬁrst state to enact legisla?on that implements parts of the Paris climate agreement. The Hawaiʻi Climate Change Mitigation and Adaptation Commission has been established, and it is to provide direction, coordination, and planning, develop strategies, and complete a Sea Level Rise Vulnerability and Adaptation Report. • There are websites that show the different types of sea level rise impacts. • Because of the sea level rise, king tide events will get more severe, and there may be flooding during regular high tides. • Passive models can underestimate the effect waves may have, and it is expected they will frequently overtop the coastal bench.