A recent meeting at the United Nations showed that floating cities and islands will be increasingly needed when sea level rise accelerates:

OCEANIX Website

Marine Habitat Regeneration

Waterworld? Floating Cities Turn Hollywood Sci-fi Into Reality As Sea Levels Rise

Tom Goreau, President of the Global Coral Reef Alliance discusses how two innovative materials will make these possible. 

First, Biorock reefs on the bottom provide growing anchor reefs for mooring points, creating bottom reefs that get stronger with age and cement themselves to the bottom, while floating Biorock reefs around floating islands dissipate wave energy and increase fisheries production. 

Second, EPIC floating concrete provide floating stable foundations.