During the ice ages of the past million years, the level of the sea has risen and fallen. Because Florida and the coastal plain is flat, this has meant a great change in the total land area. {...the Florida shore line at a time between Ice Ages when the sea level was high.} Since southern Florida is especially low and flat it is interesting to speculate on possible changes in the shore line which may come about if the world climate becomes slightly warmer or colder during the next century or so. (Land From the Sea p.37)