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MARI/CCPO Seminar Series
Coastline Shapes Respond to Changing Storms: Morphodynamics, Coupled with Human Dynamics
Dr. Brad Murray, Nicholas School of the Environment, Duke University
As the statistics of storms (tropical and extra-tropical) shift with global warming, the wave climates affecting coastlines will shift. In response, we can expect coastline shapes to change—with associated intensification and changing locations of large-scale shoreline erosion zones. Observations from the cuspate capes of the Carolina coastline, USA, where a shift in wave statistics has been documented, provide a test of this prediction. Along underdeveloped cape shorelines, the difference between historic and recent shoreline change patterns conforms to model predictions. However, on the developed Cape Fear, long-term shoreline stabilization (through beach nourishment) precludes the predicted changes in coastline shape. In this location, model experiments coupled with observations of cumulative beach-nourishment sand volumes indicates that the response to climate change exists within the human component of the coupled human/natural system.
Because shoreline stabilization decisions, made in response to coastline changes, affect large-scale coastline change, the present and future evolution of developed coastlines results from coupled physical and human dynamics. Coupling economic and coastline-evolution models leads to the conclusion that patterns of coastline change and alongshore distributions of property values are co-dependent. Analyzing the holistic results of different coastal management decisions made by different stakeholders along a common coastline requires taking human/coastline coupling, as well as wave-climate-change scenarios, into account. A stakeholder-initiated study of coupled dynamics on the Virginia coastline, USA, provides an example.