I'm writing a sci-fi/fantasy story that partially takes place in a supercity (Pop 15 Bil) made of skyscrapers. The inhabitants thereof are immortal, and so don't have to be concerned about atmospheric things like breathing at such insane heights and the like, but my question centers around the following:
How much louder would people have to speak at the top floors to talk over the wind?
Approximately how complex would the transportation of industrial materials be?
Could there be walkways between buildings without barriers to protect from wind?
What would the energy consumption be like, and what solutions would/could there be to keep up with it?
Any other things you think I should consider?