This is my view of the 'end of the world' issues and situations:
The earth itself will be here for a VEEEERY long time.
We might not be.
Like any other species - we are also prone to extinction.
Any possible extinction will be an end of *our* days - not necessarily an end to a dog's days or an elephant's days - but ours and ours alone. . . not even the earth's - in fact - it might be the opposite for other species. With us gone many might flourish and only natural selection will finish off others.
The things that give us a hands up in the 'preventing our own extinction' situation is that we are capable of *causing* our own extinction, *knowing* something might happen, *informing* others that it might happen, *preventing* it from happening if we want, and *avoiding* it in the future based on what we learn in the past.