A dramatic rise of sea levels by the end of the century could wipe out some of America's barrier islands off its eastern and southern coasts, researchers said on Tuesday.
"Barrier islands may really look quite different in the future for our children's children," Laura Moore of Oberlin College's geology department told the fall meeting of the American Geophysical Union. "Barrier islands may become vulnerable to threshold collapse."
Narrow barrier islands ring much of the East and Gulf Coasts of the United States, protecting the mainland from storms, providing refuge to wildlife and offering vacation possibilities to beach lovers.
Some of the barrier islands are quite built up, like Miami Beach, an international tourist lure. Others like the Chandeleur Islands off New Orleans are uninhabited but home to birds and wildlife. Fire Island off Long Island offers a vacation refuge where typically wary New Yorkers often do not lock their doors.
The Intergovernmental Panel on Climate Change estimated in 2001 that the world's seas will rise by between nine and 88 centimeters (3.5 and 35 inches) by 2100. Scientists who study America's barrier islands worry about what could happen if the higher estimates come to pass amid global warming.
"Potentially we're looking at the failure of barrier islands," said Asbury Sallenger, an oceanographer at the U.S. Geological Survey.
He showed images of the Chandeleur Islands off the Gulf of Mexico, which were decimated by Hurricane Katrina last year and continued to erode.
As part of a natural process barrier islands often retreat over time toward the shore, but homeowners' desire to rebuild what is lost in storms could complicate the natural cycle.
"If we prevent barrier islands from migrating we will then prevent them from moving to higher elevations and they will eventually be perhaps more prone to catastrophic failure," said Moore, who has studied the evolution of North Carolina's Outer Banks.
Sallenger cited Dauphin Island off the coast of Mobile, Alabama, which has suffered major damage four times since 1979 and was four times rebuilt.
"We have to be far wiser about how we rebuild," he said.
Ultimately, the erosion of barrier islands is a long fight Mother Nature is likely to dominate.
"If sea level rises too fast there may be little we can do in the very long term to prevent failure from occurring," Moore said.Reuters
