Rising Seas Called Threat To Shore and Bay by 2100
Friday, May 23, 2008
Rising sea levels could swamp sections of the Eastern Shore, eat away islands in the Chesapeake Bay and submerge long stretches of Atlantic Ocean beaches by 2100, according to a report released yesterday by the National Wildlife Federation.
The report says a computer model was used to simulate the effect of a 27.2-inch rise in sea levels triggered by global climate change. It says that kind of a rise was at the upper end of forecasts by the United Nations' Intergovernmental Panel on Climate Change, a conference of scientists from around the world.
Using this model, the report presents a more detailed picture of a problem that others have already sketched. The Chesapeake region, rimmed with marshes and other low-lying land, would be one of the hardest-hit areas in the country if warmer temperatures drive water levels up, the report says.
"If you want to find a poster child for climate change, there are only a handful of places . . . that stand out," said Patty Glick, a wildlife federation scientist who worked on the report, "and the Chesapeake Bay is definitely one of them."
The region is unusually vulnerable to rising seas, scientists have said, because the land is already sinking, in part because of geological changes that date to the last ice age. The report estimates that in some parts of the region, water levels rose a foot in the past century and that about half of that change was attributable to natural subsidence.
In the next century, the report says, waters could be pushed upward as polar ice sheets melt and as warmer temperatures cause oceans to expand. Around the bay, more than 167,000 acres of dry land and 161,000 acres of brackish marsh could disappear, replaced in many cases by open water, the report says. The total area lost would be larger than Fairfax County.
The worst consequences, the report says, would fall on the bay's islands and the Eastern Shore. Washington, Baltimore and Richmond are on the western side of the bay.
At Blackwater National Wildlife Refuge, a vast area of swamps on the lower Eastern Shore, 90 percent of some marshes could turn to open water by 2100, the report says. In the lower Chesapeake, large parts of Smith Island, Tangier Island and Deal Island might wash away.
On Virginia's Eastern Shore, the report says, 80 percent of beaches on the Chesapeake Bay and Atlantic Ocean could vanish. In the Hampton Roads cities of Norfolk and Virginia Beach, the report says, 79 percent of the beaches could be lost if steps are not taken to add more sand.
Glick said the foundation was particularly concerned about the effect on wildlife, including fish, frogs and marsh birds. Some animals are highly adapted to one ecosystem, she said, and might not be able to adjust if their habitat is inundated. "We're throwing changes at them . . . in a blink of an eye" in evolutionary terms, Glick said. "So I think there's very, very legitimate concerns."