| Whether you believe that man has had any effect on earth’s climate or in global warming, the science is out there to show that the sea level along the Gulf coast is rising. The world’s oceans have been on the rise since the peak of the last ice age over 18,000 years ago. Sea level is rising along most of the U.S. coast and around the world. In the last century, sea level rose five to six inches more than the global average along the Mid-Atlantic and Gulf coasts because coastal lands there are subsiding.
The combination of sea level rise and land subsidence is referred to as relative sea level rise. In most journal articles and government reports on sea level rise, Louisiana is listed as the area to be most impacted by relative sea level rise. While Cameron Parish’s coastal area is experiencing the least impact of any coastal parish from relative sea level rise, the impact still is quite significant.
The two National Weather Service tide stations to Cameron’s east and west, which have more than 100 years of data, show an average relative sea level rise of 5.66 mm per year for Sabine Pass, Tx., and 9.65 mm per year for Eugene Island, La. This converts to one third of an inch per year or three inches per decade. Three inches over a decade does not seem like much until you consider that much of Cameron Parish has an elevation of three feet or less.
What does this mean for Cameron Parish and its residents?
- Let’s assume that a high tide of three feet puts water in the streets in downtown Cameron. A three-foot tide is not the norm, but does happen several times per year. Using the three-inch per decade average in relative sea level rise, in 30 years (nine inch increase in relative sea level) a two-foot, three- inch tide will put water in the streets. The impact: A two-foot, three-inch tide is quite common.
- Assume the life of a tidal marsh management project with water control structures is 30 years. The management goal of the project is constructed to maintain water levels at a set water level.Over the 30 year life of the project, tide water levels will be 9 inches higher than planned for, making management goals of the project nearly impossible.
Relative sea level rise will affect every aspect of coastal activities.
This is not meant to alarm anyone, only to raise awareness and to plan for sustainable future activities. Anyone who has lived on the coast for 30 years or so realizes in normal years there is more water to land ratio than ever before.
For more information, visit www.epa.gov/climatechange/effects/coastal/index.html , http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml , http://sos.noaa.gov/datasets/Ocean/sea_level.html .
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