Every year, 25-35 square miles of land off the coast of Louisiana—an area larger than Manhattan–disappears into the water due to a combination of subsidence (soil settling) and global sea level rise. The maps at right show how much land has been lost to the Gulf of Mexico in the past 80 year. The second image shows the state of the coast in 1932. The image combines the 2011 satellite image with a U.S. Geological Survey map in which land areas that were present in 1932 are light gray. Since the 1930s, (source : NOAA ; Underwater: Land loss in coastal Louisiana since 1932 (click under the picture to see the two maps), on line 2013-04-04