40 percent of the population lives within 62 miles of the ocean. High tides and storm surges put millions of lives and billions of dollars of property endanger. Natural protections against damaging storm surges are increasingly threatened. Barrier islands, beaches, sand dunes, salt marshes, mangrove stands, and mud and sand flats retreat inland as sea level rises (unless there are obstructions along the retreat path) If they cannot move, these natural protections are washed over or drowned.Also a rise in the sea level makes saltwater intrude into the groundwater and contaminates it.

Sea levels

Since 1870, global sea levels have risen by about 8 inches.