It used to be that civilizations pivoted on points at crossroads: Greece, Iran, Gibraltar, Stalingrad, Vicksburg. The future of technocivilization's colonialist extraction Empire (resources flowing toward cities) will be decided on the high ground near every coastal city where refugees coming out are trapped in a battle line against food producers and land dwellers demanding retribution. There will be a fossil record of shopping bags, burned cars and Crocs leading back to sunken skyscrapers, radioactive or not. 200 ft: that's the future's number, whether in 10 years or 200 years, it's just a matter of when the perception of "coastline" hits the delusion of our collective ego. Maybe they'll make a movie.