Don Paul, a television meteorologist from Buffalo NY that I follow on Facebook, has an excellent description of why sea levels are rising and the consequences of both rising sea levels and subsidence of land on coastal cities and ecosystems.  You can read it at https://buffalonews.com/2017/02/03/don-paul-ominous-duo-rising-seas-sinking-land/.

The Mississippi River meanders through New Orleans, while Lake Pontchartrain sits at lower right, in this photo taken from the International Space Station in 2014. (NASA file photo)