Pretty soon, Roland Emmerich is going to run out of ways to destroy the world. He’s already used up aliens, global warming and now, an ancient numerological prophecy that predicts doom on Dec. 21, 2012.

He’s burning through options quick. What’s left to be the next cause of global catastrophe? Nigerian scammers? Those guys who wash your windows uninvited at traffic lights? Fox News?

Maybe it doesn’t matter, because the disaster impetus is hardly what’s fueling Emmerich; he just wants to blow crap up, and if you’ve seen “Independence Day” or “The Day After Tomorrow,” “2012” will merely be an exercise in repetition. Hammy dialogue and sappy melodrama punctuated by unmitigated disaster at every turn can only be done so many ways.

“2012” features a cast led by Chiwetel Ejiofor (“American Gangster”) as White House scientist Adrian Helmsley and John Cusack (“War, Inc.”) as hack author Jackson Curtis. Helmsely forecasts doom due to increased solar activity that will eventually disrupt the earth’s core, causing the earth’s crust to shift and earthquakes and tsunamis to overtake the world.

He advises President Thomas Wilson (Danny Glover, “Saw V”), flirts with the president’s daughter Laura (Thandie Newton, “W.”) and grapples with fellow adviser Carl Anheuser (Oliver Platt, “Year One”). A plan is put into motion to build “arks” that can save as much of the human race as possible.

Curtis, meanwhile, is the pseudo-deadbeat dad who wants to connect with his wife (a shrewish Amanda Peet, “Martian Child”) and kids (Liam James, Morgan Lily), but is in desperate need of a crisis to show him the error of his ways. Good thing the apocalypse is on its way!

Woody Harrelson (”Zombieland”) makes an appearance as a kooky conspiracy theorist, and George Segal and Blu Mankuma are a couple of aging musicians on a cruise liner. There’s also a wealthy Russian magnate, his brutish twin sons and his bimbo girlfriend (Zlatko Buric, Alexandre and Phillippe Haussmann, Beatrice Rosen).

And wouldn’t you know it, all of these characters’ lives are going to intersect as the end of the world brings them together. It’s like watching a three-year-old’s take on Robert Altman.

Now, to Emmerich’s credit, his preposterous action sequences are a lot more fun to watch than Michael Bay’s testosterone gushing — Emmerich’s inherent cheesiness is far preferable to Bay’s super-serious perfectionist posturing.

But still, should watching this kind of thing be fun? Emmerich destroys entire cities with a flick of the wrist. A scene with Curtis and his family fleeing Los Angeles with the earth literally caving in behind them is undeniably exciting, but should this kind of purposeless human and property annihilation pass as entertainment?

Obviously, it’s just a film, but two-and-a-half hours-plus of the fetishism of destruction is a little unsettling.

Compounding the matter is the fact that “2012” has very little to say; there better be a damn good payoff if nearly the entire human race is going to be wiped out for the purposes of this film.

There isn’t one. Emmerich closes his bloated opus with a little girl’s revelation that she’s overcome wetting the bed. Now that’s profound. Definitely worth 6 billion lives and civilization as we know it.