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East Coast May Feel Rise in Sea Levels the Most
Researchers are finding that climate change could bring new bad luck by untracking a system of ocean currents that performs the astounding feat of keeping the sea here below the average sea level.
They say it works like this: Warm water from the south Atlantic flows north along the coast, cools off and sinks. That sinking happens on such a vast scale that the Atlantic's surface is lower here, a depression in the ocean 28 inches deep. But two new studies have shown that climate change could make northern waters warmer and could dump a disruptive flood of fresh water from melting glaciers in Greenland.
"You're getting less sinking, because [fresh water] is less heavy, it doesn't sink as much. That kind of slows down this whole conveyor- belt thing," said Gerald Meehl, a scientist at the National Center for Atmospheric Research in Colorado whose study of this phenomenon came out last week.
"You'd get an additional one or two feet over this global sea-level rise" along parts of the coast, Meehl said, an effect that would be strongest in the Northeast.
Another study last month found a threat from a Texas-size ice sheet in Antarctica. If it broke off and melted, the shift of mass from pole to ocean would change both Earth's gravitational field and its rotation.
The result? Still more water would slosh to the U.S. Atlantic Coast, along with the Pacific Coast. But in this case, it would probably not happen for centuries.
Scientists concede that these predictions could be flawed or flat wrong.
Even if they are right, New York still isn't in the same danger as New Orleans. Even a yard of sea-level rise, they say, would not put any major East Coast cities underwater. But higher waters would mean bigger storm surges, a greater chance of flooding on rivers such as the Potomac or the Patapsco in Baltimore.
It could be a much bigger problem for barrier islands and marshes, which are typically just a few inches above the water. Even before the recent research forecast accelerating rise, Blackwater National Wildlife Refuge -- a rare, vast marsh on Maryland's Eastern Shore -- was predicted to become mainly open water by 2030.
So some researchers have already begun thinking about how to defend the coast. Professors at the State University of New York at Stony Brook have suggested building barriers that might pop up during big storms and seal off the city's water like a bathtub. The fishing port of New Bedford, Mass., has had such a "hurricane barrier" since the 1960s.
In the Washington region, Environmental Protection Agency official James G. Titus said, Hains Point, along the Southwest Waterfront, and K Street NW in Georgetown might have to be elevated. Sections of the waterfront Fells Point neighborhood in Baltimore might also need to be jacked up.
And, Titus said, rural areas along the water might have to be abandoned. On Maryland's Eastern Shore, for instance, rising seas could eat up large sections of marshy Dorchester County.