January 8, 2007 -- A recent study conducted by Oberlin College Assistant Professor of Geology Laura Moore looked at how climate change and sea-level rise will potentially impact the future existence of barrier islands by examining the barrier coast between Rodanthe and Cape Hatteras, North Carolina Outer Banks.

The results of her study suggest the Outer Banks of North Carolina, a world famous barrier system, may become vulnerable to collapse if sea-level rise by the year 2100 exceeds the Intergovernmental Panel on Climate Change (IPCC) estimates.  Based on observations of barriers in Louisiana, where barriers are currently collapsing due to limited sand supply and rapid sea level rise, the results of Moore’s study suggest that barrier collapse may occur in the Outer Banks if sea level reaches 1.4 – 1.9 meters above modern sea level by the year 2100.

Barrier islands front a large percentage of the United States Atlantic and Gulf of Mexico coasts.  These narrow, low-lying, sandy landforms attract increasing numbers of coastal residents and support trillions of dollars in coastal infrastructure despite being extremely vulnerable to storms and experiencing landward migration in response to relative sea-level rise.

According to the IPCC, sea level will likely rise between 0.09 meters and 0.88 meters by 2100 AD unless there is a substantial reduction in greenhouse gas emissions. Recent paleoclimatic evidence for ice-sheet instability suggests sea level may rise even faster—as high as 4-6 meters above modern sea level.

“How rapidly barrier islands migrate depends on a number of factors, including underlying geology and sand supply,” says Moore. “But in general, the faster sea level rises, the more rapidly the barrier islands will have to  move landward to keep up.”

Predictions for barrier island response to future sea-level rise have been limited generally to qualitative assessments based on geologic and historic records.  However, Moore used a two-dimensional, cross-shelf morphological-behavior model, GEOMBEST, to simulate the response to sea-level rise of the North Carolina barrier coast in her study, along with data on past barrier island migration.

Moore conducted her study with Jeffrey H. List, S. Jeffress Williams, and David Stolper at the the USGS Woods Hole Science Center in Woods Hole, Massachusetts.  Moore was a visiting scientist at the Woods Hole Science Center while on sabbatical from Oberlin College during the 2005-06 academic year.

Prior to joining the Oberlin College geology department in 2002, Moore was a research associate at the College of Marine Science/USGS Center for Coastal Geology at the University of South Florida in St. Petersburg. She earned a B.A. in Geology at Colgate University (1993) and Ph.D. in earth sciences at U.C. Santa Cruz (1998).

Related Links:
- Reuters Foundation Article