If the world was so great outside.....*spoiler*

Yeah, the movie never really explained what exactly happened that caused everyone to live in a domed city in the first place. Since the buildings of Washington DC were mostly still standing, it doesn't seem likely there was a nuclear war. Maybe it was some sort of plague or environmental catastrophe which poisoned the atmosphere.

Whatever it was, it had cleared up and the planet was recovering - but nobody told the people inside the domed city (or the computer malfunction prevented them from finding out). It's possible that there may have been other smaller shelters scattered about which would have allowed for other pockets of survivors (some of whom apparently liked cats). That would explain the presence of the old man and all those cats.

"The environmental deniers must love this one. All the problems in the world are all just a big lie, the global warming talk and overpopulation and wars are just BS by the leftist media."

Nope, that's your take on it.

The movie is a kludge of the original novel. Read it?

The domed city is a metaphor for the all-powerful state, controlling its citizens with imagined threats. You might do well to imagine how the state you live in could control you with threats of environmental disasters. Do what you're told or terrible things will happen. Obey and all will be well. Huh?

Runners are non-believers, right? But what is it they don't believe in? They don't believe in what the state is telling them. So what is your state telling you? And do you believe it? Are you a runner?

Or do you believe what the state is telling you? Isn't the message from the state that environmental disaster is nearly upon us? Do you believe it? If you do, then maybe the "environmental deniers" are the runners and you are a Sandman.

ISIS set off a dirty bomb in New York. The politicians in Washington went underground, and their descendants were living in the City.