Sea level rising will effect different parts of the world differently. It is impossible to make blanket statements about rising levels. The biggest effect will come on island nations, as they could be totally submerged. Less so on contents with mountain ranges close to the shoreline. If you spend enough on infrastructure, most cities can be saved.

That said, NYC has serious infrastructure problems. I was there during hurricane Sandy and it completely submerged the subway system. An even bigger problem is that most electrical transformers are under ground and if flooded explode. The question for NYC is how much will it cost to keep the city from flooding, and will it be worth the cost?

In studying climate change I've learned often there are two agendas: pro and anti capitalism. In almost every situation the truth lies somewhere outside either agenda.