Oh yes, the world is totally going to end. Just like they've been saying for thousands of years.
Honestly, just to end civilization as we know it would take the destructive force of thousands of Japanese earthquakes all over the world. Bar a massive stray asteroid impact (rather rare as it is, and now we are looking for them) or nuclear war, I don't think it is going to happen. Unless soon is a couple of billion years for you, then the sun will swallow us up.
You know, I really hate the phase "end civilization as we know it". It's not because of any specificity with the people who use it.
It's because the phrase is SO [CENSORED] AMBIGUOUS! Because civilization as we know it could end if we suddenly had a giant computer singularity in 3 minutes, that decided that the only way for it to survive was to micromanage human's lives.
Or random dudes&dudettes J through P all get locked in cryostasis or some other wierd top-secret "does not officially exist" government project, and then they get warmed up seven hundred years from now, only to find civilization as they knew it has "ended", because it now is radically different to what they knew, despite being in cryo-sleep or hibernation or whatever for seven hundred years.
Incidentally, the second situation is somewhat of a plotline to some movie I remember glimpsing the first five or ten minutes of.
But yeah, the term has no implicitly negative or positive connotations, and it wouldn't take much to end civilization as we know it. I mean, really, if we were to facilitate a rapid (less than six months), total switch to nuclear power generation, then civilization as we knew it would end, because it would no longer be dependant on a primarily oil and coal based power economy.