tide goes out, beach erodes. tide comes in, beach un-erodes.
there have been some erosion problems, as all beaches have. nothing like the beach is sinking though. i remember when i was a kid....my grandparents would take us to atlantic city....back before the casinos turned it into "ghetto by the sea".
when the tid would come in, it nearly came all the way up to the boardwalk. it doesn't come that far anymore.
so much for ocean levels rising.