Trivia: In every Final Fantasy video game, and the movie, there is a person named Sid (even though sometimes it's spelled with a 'c').
Trivia: Something to look for: somewhere in the film, the animators placed a Chocobo (one of those ostrich-like chicken things that people ride on in some of the Final Fantasy games). It's on the top right corner of Aki's shirt, almost the same color as the shirt, when she wakes up from her 2nd dream.
Chosen answer: The environment has become too hazardous for humans to tolerate.
Paul Plesser