. The 208-foot-tall Cape Hatteras Lighthouse was just moved more than a quarter mile from its previous perch, where it was threatened by sea encroachment. Coastal erosion stripped away about 1,300 feet of beach, bringing waves within 150 feet of the 4,800-ton sentry. When the light was erected in 1870, it was about 1,500 feet from the waves. The lighthouse, on the Outer Banks, North Carolina's long barrier beach, was built to warn ships from waters called "the graveyard of the Atlantic." Ironically, the move should serve as a warning about the growing problem of coastal erosion. Erosion doesn't just plague the Outer Banks. Coastal residents up and down the United States are worried about weakening reefs, disappearing beaches and occasional homes plunging into brackish water. Beaches are in constant motion, accumulating here and eroding there, in response to waves, winds, storms and relative sea level rise. Yet when everyday people like you and me, and celebrities like Steven Spielberg, build along the beach in places like Southampton, New York, we don't always consider erosion. After all, real estate transactions rarely close during hurricanes or the Northeast, which cause the most dramatic damage to beaches. Yet Southampton, like all barrier beaches that protect land from the sea, is vulnerable to annihilation precisely because of the factor that makes it so fascinating: the sea. And the problem is growing because the sea is rising after centuries of relatively slow rise, and scientists predict that the rate of rise will continue to increase over the next century. Even the earth, in many places, is slowly sinking. The result is a loss of sand that places beach homes uncomfortably close to or in the water. However, erosion cuts in two directions. Without the process of erosion, we would not have the beaches, dunes, barrier beaches, and highly productive bays and estuaries that owe their very existence to the presence of barrier beaches. Erosion of glacial landforms provides most of the sand on Massachusetts beaches. A popular destination The problem of beach erosion has many causes. Among these are: · The omnipresent desire to live near the sea. · A historically rapid re... center of the chart... er - as determined by the grounding line - the result appears to be relative stability. “Ice flows do not appear to be susceptible to the kind of unstable retreat once predicted,” Bentley says. “Their flow is largely insensitive to the presence of the ice shelf, so the grounding line would remain the same.” Instead of a possible collapse in 100 years, as was considered possible 10 years ago, Bentley says the West Antarctic Ice Sheet is more likely to collapse - if at all - perhaps in 5,000 years at the earliest. Dean, Cornelia. Against the Tide: The Battle for America's Beaches. New York: Columbia UP, 1999. Hanley, Robert. As beaches erode, a debate over who will pay for repairs. The New York Times, April 20, 1998, P. A1. Kossoff, Julian and Kate Watson-Smyth. Fake beaches devastate marine life. The Independent (London), 2 August 1998, p. 5. Moran, Kevin. The future of beach homes is as uncertain as quicksand. The Houston Chronicle, May 1, 1999, p. A1. Lambert Bruce. Lines in the sand: the beach as a battlefield. The New York Times, May 23, 1999, p. LI14. Martin Douglas. Report warns New York of the dangers of global warming. The New York Times, June 30, 1999, p. B5.