Friends who have seen "the Al Gore movie" report that some of its most compelling images are computer simulations that project sea level rise resulting from global climate change. The EPA has been modeling this for some time, now, and the impacts in the US are particularly dramatic from the Mid-Atlantic States southward. The outer banks of North Carolina and low-lying areas far inland are particularly vulnerable as this dramatic EPA map illustrates.
The implications of sea level rise, and models that anticipate warmer ocean temperatures and therefore more severe storms affecting coastal areas, are sweeping in scope and complexity. According to Coasts in Crisis by Don Heinrichsen, writing in September 1995 for AAAS, the publishers of Science:
"In the United States, 54 percent of all Americans now live in 772 coastal counties adjacent to the Atlantic and Pacific Oceans, the Gulf of Mexico and the Great Lakes. Over the past 30 years, coastal populations have grown by 41 million, faster than the country as a whole. The Washington DC-based Population Reference Bureau reports that, between 1960 and 1990, coastal population density in the United States increased from 275 to nearly 400 people per square kilometer. By the year 2025, nearly 75 percent of all Americans are expected to live in coastal counties; with population density doubling in some areas such as Florida and southern California."
The densely populated, high value property along our Atlantic, Pacific and Gulf coasts provides essential ecosystem services as well. Barrier beaches and dune systems blunt the force of hurricanes, while tidal estuaries and coastal wetlands filter pollutants and sustain fisheries. In most states the wet beach is where private property ends and public access begins- unless private property owners armor the beach and sea level rises, eliminating the public land between low and high water.
It was precisely this concern that prompted Texas, not usually considered to be on the cutting edge of conservation innovation, to adopt a broad collection of arrangements under which human activities are required to yield the right of way to naturally migrating shores. The problem in Texas was that if private property owners were allowed to erect bulwarks and buttresses against the sea and sea levels continue to rise, Texans would lose their treasured right to drive along the beach. The concept of the "rolling easement" emerged from Texas Common Law and allows private land owners to develop their shore front property but does not grant the right to hold back the sea. Usually, rolling easements kick in when water levels reach a certain level, and they have been used
The EPA's James Titus is an authority on managing for sea level rise and has written extensively and articulately on tools like rolling easements that work with landowners to allow the inshore migration of coastal wetlands and preserve the public rights of shoreline access.
"Rolling easements seem more likely to succeed on a broad scale. These policies do not require a particular line to be drawn on the map. Their impact on current property values would generally be less than 1 percent. Governments could afford to compensate riparian owners; and even a failure to compensate them would impose a minor burden. Developers who deny that the sea will rise would view the policy as costing them nothing. Unlike setbacks, rolling easements allow landowners to decide how best to use their property between now and whenever the land finally erodes. Nevertheless, enforcement may be politically difficult. A combination of density restrictions, setbacks, and rolling easements would probably be more successful than relying on any single option."
Titus is a very engaging speaker. I once saw him hold a large convention of wetland scientists absolutely spellbound rapt attention: part revivalist preacher, part car-salesman, and always thought provoking and focused on practical solutions to a complex problem. Get him for your next Rotary luncheon or corporate breakfast and you will not regret the effort.
80% of our tidal shorelines lie inland of our oceanfront. Some forward thinking conservation organizations are using predictive models to identify not only those low-lying areas vulnerable to flooding with sea level rise but incorporating types of land-cover into a cost/distance analysis for inland migration of coastal wetlands. Hard surfaces and built areas are less likely to become the salt marshes of the next century than open fields or forestland. It is then possible to select areas that are most likely to be coastal wetlands in the future and conserve them today when they are currently dry and open.
Some savvy landowners are negotiating conservation easements on their waterfront properties with floating building envelopes that retain the right to relocate a house threatened by rising seas to higher ground where development is otherwise restricted under the easement. I am negotiating one such easement for my family's land on Buzzard's Bay as we speak. Easements are meant to be perpetual and the ability to anticipate dramatic changes in a few short generations will be increasingly neccessary as climate shift produces to altered habitats and shorelines. Rolling easements will not hold back the sea, but nor should they close all avenues of retreat.