Megalopolis facing sea level rise

Devastating hurricanes, torrential rains, the inexorably rising waters: coastal megacities are now up against the wall. The filmmakers have chosen three emblematic cities: New York, Singapore and Rotterdam. Cities that each face unique problems and must revisit their relationship with water in order to survive on the long run. In 50 years, all surge barriers in the world will be out of order. What solutions will then remain for coastal cities?