The new New York City would balance the relationship between the information networks that the metropolis depends on and Earth’s finite resources.
All vital components of life would be monitored and attuned to the needs of every organism, not just humans. Supplies of food and water, our energy and waste and even our air would be sensibly scrutinized. Thanks to masses of miniaturized low-cost electronic components deployed across the city, communication becomes far easier. New York will grow and adapt to millions of new minds entering it everyday.
The city would make sure every need is provided for within its borders. How we provide nutrients, transports, and shelter would be updated. Dilapidated buildings would be replaced with vertical agriculture and new kinds of housing would join cleaner, greener ways to get around the city. What were once streets become snaking arteries of livable spaces, embedded with renewable energy sources, low-tech, green vehicles for mobility and productive nutrient zones. The former street grid could provide the foundation for new flexible networks. By reengineering the obsolete streets, we can create robust and ecologically active pathways.
While all this may sound optimistic, some of this city of tomorrow is already taking shape... see:
http://www.bbc.com/future/story/20140402-a-vision-of-new-york-in-2050