As I watch movies that include scenic views of coastlines, I often imagine what the scene will look like in a century, two centuries and on into the next millennium. Current rates of sea level rise will not decrease until the onset of the next ice age tempers the global warming induced by the increasing level of greenhouse gases. As current coastlines are submerged, they will become part of the continental shelf.
The continental shelves are not considered part of the ocean floor proper, but as the flooded margins of a continent. It is the stretch of the seabed adjacent to the shores of a particular country to which it belongs. The shelf break of the continental margins is located at a current uniform depth of 460 feet. This depth marks the ancient shorelines of the continents during past ice ages, when the sea level was lower than it is now.