A portion of land larger than Manhattan is disappearing off the coast of Louisiana each year due to soil settling and a rise in global sea levels, NOAA says.
The agency has released two maps demonstrating the coastal land loss that took place between 1932 and 2011.
"Storm surge—the water from the ocean that is pushed toward the shore by the force of storm winds—takes advantage of the problems caused by subsidence and global sea level rise. Because much of the Louisiana coast is very low in elevation and gradually converting to open water, entire neighborhoods, roads, and other structures are vulnerable to even small storm events," the agency said in an article posted to NOAA's website.
In addition to the potential loss of infrastructure along coastal Louisiana - estimated to be worth $150 billion - coastal land loss puts wetlands at risk.
"The swamps and marshes of coastal Louisiana are among the Nation's most fragile and valuable wetlands, vital not only to recreational and agricultural interests but also the State's more than $1 billion per year seafood industry," said S. Jeffress Williams of the U.S. Geological Survey, in a statement.
"The staggering annual losses of wetlands in Louisiana are caused by human activity as well as natural processes. U.S. Geological Survey scientists are conducting important studies that are helping planners to understand the life cycle of wetlands by detailing the geologic processes that shape them and the coast, and by providing geologic input to models for mitigation strategies."