Changes in sea level, great and small

A map of the locations visited on this field trip. Click to see context. (Satellite image from NASA with map drawn over top. More about the map)

The level of the sea is always changing. These changes may be small and short-lived, as when water rushes up the beach after waves break, but others are large and long-lived — as has been the case with the post-glacial rise of the present era.

Small-scale sea level changes are part of the charm of our coastal zones. There is something relaxing about waves moving up and down the beach and the daily waxing and waning of the tides. But large-scale sea level change is usually anything but relaxing. Storms can bring water onshore to levels that cause disasters. Hurricane Katrina caused a twenty-seven-foot rise along parts of the Mississippi coast in 2005, and Hurricane Fran caused a twelve-foot rise when it came ashore on Topsail Island. Such “storm surges” change the shape and topography of the coastline and damage roads, buildings, and utilities. Sea level rises of this scale and with such grave consequences receive extensive media coverage, but the slow, steady change that occurs as the climate warms receives much less attention. These gradual changes, though, underlie and contribute to the frequency and severity of storm driven rises.

The evidence of long-term sea level change can be found everywhere along the North Carolina coast, in part because sea level is rising relatively rapidly here, and in part because many areas along our shoreline are so flat that small changes in sea level influence broad areas of our landscape. This field trip will show you what to look for to see this evidence for yourself. It is based on an actual field trip described by Stan Riggs and me in a book entitled Driving Tours to North Carolina Natural Areas (UNC Press, 2000). Both the actual and the virtual trips take you to the “Down East” part of Carteret County, a flat, gently sloping landscape that is gradually being flooded by rising sea level.

Other stops on this virtual trip show you places along our ocean shoreline where property is threatened as a result of coastal erosion caused, in part, by the gradual rise in sea level.

next