I think that what they mean by the planet dying is more or less humanity. I think that there will always be life on the planet after Lavos. All it takes is one cell, whether bacteria or whatever. And also don't forget that the Sun is a constant energy source of a planet. trees and other plant life use the sun as energy. Unless the sun blacks out, there will always be an energy source for the planet. And there are mutants and wild animals on death peak. The planet will revive itself eventually, but human life would be over. There is still water on the planet and it even rains/snows in 2300 AD. As long as there is water, Sun, and an atmosphere, there is a chance that life can happen. I agree with Paradox.