SMALLER LOUISIANAThe image below shows the Louisiana coastline in 1932 on the left and 2011 on the r

SMALLER LOUISIANAThe image below shows the Louisiana coastline in 1932 on the left and 2011 on the right. You can see a dramatic decrease in land mass over the last 80 years. Each year, about 40-55 square kilometers (25-35 square miles) of coastal land is lost. Over the entire 80 year period, about 3,058 square kilometers (1,900 square miles) of land has disappeared. Many factors work together to remove the coastline in this vulnerable area. Soil settling, or subsidence, sea level rise, and storm surge from tropical systems all work to eat away at the marsh land. Levees and navigation corridors help prevent floods, but also prevent silt from replenishing the delta. Canals dredged for oil exploration and vegetation loss caused by nutria have not helped the situation. Relative sea level rise is a measure of the change in sea level compared to the land elevation. It is a combination of many factors including global sea level rise and subsidence. In southeast Louisiana, the rate of relative sea level rise is about 1 meter every 100 years.Louisiana Highway 1 is the only roadway connecting Port Fourchon and Grand Isle to the mainland. Port Fourchon is a major port for the oil and gas industry. There are now some areas of the LA-1 highway that are less than a meter above sea level. Even weaker storms now require closing the highway, disrupting transportation. This trend will continue over the next several years as the area becomes more and more vulnerable to the storm surges from tropical storms and hurricanes.Some work has been done on Grand Isle and other barrier islands to stop erosion and build up the islands for storm protection. The areas in green on the right side image show new land added since 1932. Areas around Port Fourchon are being shored up with levees and stronger structures.The image from 1932 was created by superimposing a 2011 NASA satellite image with 1932 US Geological Survey maps. For more detailed images, check out the links below.-AmyReferences:http://www.climatewatch.noaa.gov/image/2013/underwater-land-loss-in-coastal-louisiana-since-1932http://www.climatewatch.noaa.gov/article/2012/thriving-on-a-sinking-landscapehttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC1332684/Image courtesy of the USGS and NOAA -- source link

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