Watch the trailer. It said, human want to start over. They don't concern about the effect of altering the pass to the future event. It's like you have **** life. then you have this chance of sending your conciousness back in time into your childhood self. armed with the knowledge of misfortune that befallen you in the future, i'm sure you want to avoid any actions or events that originally bring you to your future predicament. Terra Nova is not just about visiting the past, it's about reinventing human civilization.