In an opinion piece published by Yale 360, Rob Young and Orrin Pilkey, authors of The Rising Sea, explain that planners need to assume that oceans will rise seven feet in this century.
The most recent (2007) report of the Intergovernmental Panel on Climate Change (IPCC) did not take into account the melting of the Greenland and West Antarctic ice sheets. The Panel settled on a two-foot rise this century by taking into consideration only the expansion of the oceans and the melting of mountain glaciers outside the poles. Since the 2007 report was released, melting of the Greenland and West Antarctic ice sheets has accelerated. Most climate scientists now predict that the melting of these ice sheets will be the main cause of rising sea level in this century, though the rate of future melting is still uncertain.
In describing impacts of the rising seas in this piece Young and Pilkey speak largely of cities and smaller human communities. Obviously, however, a rise of seven feet would also have a severe impact on natural communities.
The most vulnerable of all coastal environments, the authors say, are the deltas of major rivers, including the Mississippi. In the Mississippi delta, land subsidence, already occurring, will increase the rate at which seawater swallows the land. The specter of a seven-foot rise in sea level raises the question of whether efforts since Katrina to restore natural areas in the delta in order to absorb the impacts of future storms can be effective in the long term.
On the barrier islands, which stretch along the eastern seaboard, a rise in sea level of only three feet would be sufficient to prevent development, unless the islands are protected by massive sea walls. A few of the barrier islands support natural communities undisrupted by humans. “The only way to preserve the barrier islands themselves will be to abandon them so that they may respond naturally to rising sea level, ” Young and Pilkey write. The barrier islands have been shaped by the action of the sea. Possibly, their original communities will survive the rising seas, though changed.
“How High Will Seas Rise? Get Ready for Seven Feet” can be accessed online at http://e360.yale.edu/content/feature.msp?id=2230
–Mary Byrd Davis
Copyright © 2010 by EcoPerspectives
Tags: barrier islands, IGCC, Mississippi delta, Orrin Pilkey, Rob Young, sea level
