Model projects major habitat transitions on North Core Banks by 2050

What you need to know

• The model uses probabilistic projections that account for uncertainty in relative sea-level rise and high-water events. The USGS data release includes scenarios with sea-level-rise rates of 6, 12 and 18 mm per year, and high-water-event intensity changes of 0%, 4% and 8%. 12
• Across the modelled period, passive submergence of the island’s interior emerges as a dominant projected transition. Higher sea-level-rise rates increase projected interior submergence and overwash, and the projected loss of beach and dune states. 1
• The projections are not uniform across North Core Banks. The study identifies dune and unvegetated interior states as particularly changeable, and reports that modelled transitions respond more to sea-level-rise rates than to changes in high-water-event intensity. 1
• The model does not include sound-side inundation and outwash, tidal inlets, or environments below mean high water, including back-barrier marshes. The authors note that these omissions could affect the projections and may lead to some interior submergence being overstated. 1
• The work sits within a management-relevant, multidecadal modelling effort. An earlier paper describes the MEEB model’s design, processes and use of observations for calibration at North Core Banks, but it is methodological context rather than independent confirmation of these projections. 13

Why this matters

The projections highlight how sea-level rise could reshape habitats on an undeveloped barrier island, while showing why scenario assumptions and omitted processes matter when interpreting model results for coastal management. They indicate potential change, not a verified conservation outcome. 1

What happens next

A key unresolved question is how observed changes will compare with the projections as observations accumulate. The released model inputs and outputs make the scenarios available for examination, but the supplied reporting does not establish when that comparison will be made. 12

What we know

• The study models 32 km of North Core Banks from 2018 to 2050 using a probabilistic approach that accounts for uncertainty in relative sea-level rise and high-water events. 12
• The model projects interior submergence as a dominant transition, with outcomes that vary alongshore and are more sensitive to sea-level-rise rates than to the modelled changes in high-water-event intensity. 1
• The USGS data release provides inputs and outputs for scenarios using three relative sea-level-rise rates and three levels of change in high-water-event intensity. 2

What we don't know

• It remains uncertain how actual changes on North Core Banks will compare with the model’s projections as observations accumulate. 1
• The reporting does not quantify how including sound-side inundation and outwash, tidal inlets, and back-barrier marsh accretion would change the extent or timing of projected interior submergence. 1
• The supplied sources do not establish how well the projected patterns would apply to other barrier islands with different sediment supplies, elevations and physical settings. 1

Read the reporting

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