Here's a chart of sea levels for the last 500 million years:
The seas have occasionally been higher than current levels, but rarely. It's more common for sea level to be 100 m lower than for it to be at current levels.
Most of the changes in sea level observed on time scales of a human lifetime are due to changes in the land, not changes in the relative amounts of water and ice. At polar latitudes the land was pressed down by glaciers during the ice age and is slowly popping back up, moving ocean water toward the equator. Tectonic plate movements are also a factor. Meanwhile coastal land is subject to erosion, especially on barrier islands such as the one Alton Road is situated on.
This page shows sea level changes (relative to land levels) by location globally. Generally the sea level is falling at northern latitudes and rising in the tropics:
http://tidesandcurrents.noaa.gov/sltrends/sltrends.html. Around Miami the sea level rise recently has been about 2.5 mm/year or about 10 inches per century.