Rising Atlantic Erodes Waterfront Real Estate

Although the Atlantic Ocean is rising by only a fraction of an inch each year, scientists warn that the increase is enough to radically change the coastline of the northeastern United States in coming decades. The extra seawater will cause unprecedented erosion, flooding, storm damage and drowning of salt marshes.

That means built-up waterfront real estate in this heavily developed region will get damaged as beaches retreat.

Climatic warming is to blame for the accelerating rise in sea level during the last 150 years along the New England coast. The Atlantic Ocean has risen six inches (15 cm) since 1938 and now gains around one-tenth of an inch (2.5 to 3 mm) a year. Exacerbating the matter, land on this part of the North American continent is also sinking by as much as four one-hundredths of an inch (1 mm) a year.

Scientists at the Woods Hole Oceanographic Institution say they can't predict with any certainty how far Atlantic waters will continue to rise. The rate depends upon how fast polar ice melts. Conservatively, they estimate that the Atlantic will take on another 9 to 15 inches (23 to 38 cm) by 2100. But these predictions don't allow for any sudden accelerated melting of Greenland's ice sheet, which some experts believe has already begun.

Scientists also don't know enough about coastline dynamics to foretell how much waterfront property will be lost to the Atlantic. They nevertheless agree that by this century's close, the extent of eroded beaches and receded coastline in the northeast will be severe.

The additional ocean water will continually carve away shoreline. But the biggest waterfront alterations will result from severe storms such as Nor'easters and hurricanes. These can propel surf across low beach barriers and cut new inlets. The fresh channels leave previously protected portions of coastline exposed to eroding waves. Such a chain of events unfolded when a January 1987 storm breached Nauset Beach off Chatham Massachusetts, creating an inlet that eventually destroyed many homes in a new oceanside development.

Low-lying and gently-sloping coastlines are most susceptible to dramatic changes from rising waters. Storms are already eating away up to 6.5 feet (2 m) of beach a year on the south shore of Martha's Vineyard. The areas rated by the US Geological Survey as having the highest risk of being damaged by a climbing sea level lie along the shores of New Jersey, Long Island, Nantucket Island, Martha's Vineyard and southern Cape Cod.

Salt marshes are also especially vulnerable. These biologically rich ecosystems will turn into relatively austere cordgrass wetlands as the marshes drown under rising water. Several examples of the encroaching Atlantic outpacing marsh accretion exist along the east coast. Among them, inundation at Maryland's Blackwater Wildlife Refuge eliminated 5700 acres (2300 ha) of salt marsh between 1938 and 1979.