The funny thing about life is, trouble never comes from where you expect it. You spend two months worried about interviewing for that big job promotion, then on your way there, you get attacked by a pack of wild dogs. That's just the way it goes.
So in terms of worldwide disasters, while Hollywood obsesses over asteroid strikes and earthquakes and whatever the fuck 2012 was about, don't be surprised if disaster comes in the form of one of these lesser-known calamities that you'd never even heard of.
Until today, that is.
Volcanoes are badass, there is no denying that. People worship the things as gods. They can create damned land masses. And sure, Mt. Pinatubo and Krakatoa may have messed some shit up when they went off, but that's really just a problem for the people who made the rather short-sighted decision to live at the base of one.
Whatever, mountain god. We live over here.
But what if you had a really, really big volcano. A super volcano, if you will. One big enough to fuck up the whole planet.
Supervolcanoes exist, and they are to volcanoes what nuclear weapons are to firecrackers. According to Wikipedia, a supervolcano can puke out more than 240-cubic-miles of matter into the sky, which is millions of times larger than a normal eruption.
Imagine tossing all of Connecticut into the atmosphere.
They are caused by massive amounts of magma building up pressure under the crust, and not enough holes (volcanoes, geysers, etc,) to vent it all. Eventually, the pressure builds until a massive section of earth explodes. The human race was possibly shaped by one such explosion--it wreaked such havoc on the ecosystem that when it was done, there were only enough humans left on the planet to fill one high school gymnasium.
So Are We Doomed?
Maybe. There is no evidence that any of these are going to explode in our lifetime- oh wait. Long Valley in California has been showing signs of "waking up" in the past 20 years.
Foul play hasn't been ruled out.
Then there are the Siberian traps in Russia, which are quiet for now. This is very good news because it is estimated that if they blew up, they would likely cause another event like the one back at the Permian Triassic boundary 251-million-years ago... which virtually wiped out all life on Earth.