In the New York Times Magazine, Samanth Subramanian describes how Singapore reclaims land from the ocean. Less wealthy nations cannot afford these measures:
Kiribati, an island nation in the Central Pacific, has bought 6,000 acres of forested land in Fiji, more than a thousand miles away, hoping to resettle some of its 100,000 people if a crisis hits. The Maldives, similarly, has talked about buying land in Australia.
How is that going to work, I wonder. Moving a whole nation into another country will cause tremendous political, legal, social and cultural issues.