From the film, even the crazies theories of a nuclear winter weren't close. Nuclear war doesn't do much. I think a meteor or supervolcano is also impossible f

From the film, even the crazies theories of a nuclear winter weren't close. Nuclear war doesn't do much. I think a meteor or supervolcano is also impossible from the scenes in the film, not having lots of things growing within a month doesn't fit really, but it'd be an interesting discussion. Obviously this is why it's not mentioned, so people don't get wrapped up in the details about how it happen but the story.