N.C. sea level rise of 3.28 feet by 2100?

The sea level off North Carolina's coast is rising at an annual rate of 4.27 millimeters per year, a science panel advising the state of North Carolina reported this morning in Raleigh, but the rate of rise could accelerate before the end of the century and rise one meter by 2100 -- or about 3.28 feet.

The Science Panel on Coastal Hazards warned that its findings were the result of "an inexact exact science" and noted that sea level may rise by as little as 1.26 feet by the end of the century or as much as 4.59 feet. For the next 25 years the rate might continue increasing at the constant rate of 4.27 mm per year, said panel chair Margery Overton, a professor at NC State University, but changing conditions suggest the rate of sea level rise could increase.

The predicted one meter rise is an overall rate adopted for simplicity's sake, but the sea level is rising at different rates along the coast. It is rising fastest in northeastern North Carolina where relative sea level rise is marked by a subsidence of the land.

The findings were released near the end of a two-day Sea Level Rise Science Forum sponsored by the N.C. Department of Environment and Natural Resources and the N.C. Coastal Resources Commission. During Thursday's session, one researcher showed a graphic that indicated what might happen in the Wilmington area if sea level rises as much as predicted by the end of the century. The graphic shown by Benjamin Horton, a professor at Pennsylvania State University, portrayed the area of Wrightsville Beach largely under water. These are all what-if projections, of course, but they indicate what might happen if sea-level rise is as severe as some predict. Others believe it may be much more rapid as the century ends.

Stan Riggs, a coastal geologist at East Carolina University, showed graphics that indicated the coast of what is now North Carolina has been as far East as 50 to 60 miles offshore, and as far west as a line shown on popular satellite photos of the East Coast and known as the Suffolk Scarp -- a clear delineation that runs through Eastern N.C. from the Dismal Swamp down to an area west of Morehead City.

The point of research on sea level rise is not to warn the public to abandon the coast, Riggs said. "We don't have to run away from the coast, but we have to be smart about what we do," he said.

That includes recognizing that most (75 percent) of our beaches are simple barrier islands that are starved of sand and that in the event of terrible storms or excessive sea level rise, many of them will be submerged, he said. Most of our beaches are eroding at a long-term rate of 15 feet per year, and building hardened structures such as condominiums that keep the ocean from overwashing and building sand deposits on the sound side are a "long-term death sentence" for our barrier islands, he said.