Time Salvager
"Convicted criminal James Griffin-Mars is no one's hero. In his time, Earth is a toxic, abandoned world, and humans have fled into the outer solar system to survive, eking out a fragile, doomed existence among the other planets and their moons. Those responsible for delaying humanity's demise believe time travel holds the key, and they have identified James, troubled though he is, as one of a select and expendable few ideally suited for the most dangerous job in history"--Amazon.com.