My wait the simplest there is. Wait till 2012 
That's not destroying the world, that's waiting for it to end! Any idiot can do that, in fact, every idiot is. And what're you gonna' do if the world doesn't end on 2012, huh? It's not as if it's the first time it's been delayed.
A real supervillain never leaves home without having several backup plans. For me, some of my world-ending schemes include:
1). Spread a fad among the youth all over the globe that it is funny, clever, and cool to do Marlon Brando impersonations. This will cause an u[rising of http://www.youtube.com/watch?v=tWxL0fMTk-U (ABS) to sweep across the world! Soon, everyone will be too busy impersonating Brando, that they'll neglect even eating, and all production will come to a halt!
2). Replace all televised programming on all channels in every nation of the world with neverending Golden Girls marathons. Having nothing to watch except a whole bunch of old ladies talk about six will drive people completely insane, and cause them to long for the sweet embrace of death.
3). Destroy every roll of toilet paper, every toilet paper factory, and burn the plans and blueprints for every kind of toilet paper out there so that no one will ever be able to produce it ever again. This will be especially cruel. Some will forever be trapped in their own bathrooms or latrines, never able to leave the confine of their johns. Others will simply withhold their bowels eternally, until they either blow up, or are poisoned by their own wastes. A desperate few will improvise with what they can find (printing paper, leaves, their own clothing, whatever), but realize that there is no substitute and kill themselves.
