7 Doomsday Scenarios You Probably Shouldn't Worry About (And 2 You Really Should)

2. Supervolcanic Eruptions

The eruption of a supervolcano would set off a similar chain of destructive events to those that you might expect from an asteroid impact.

A supervolcanic eruption would not just obliterate everything in the direct vicinity, but it would throw enough carbon dioxide, sulfur and ash high into the atmosphere to alter the global climate, collapse the food chain, precipitate acid rain and cause mass extinctions. This is bad news for sure but, again, the threat of this may have been slightly exaggerated for the purposes of a good headline.

The image of a broiling reservoir of magma building under Yellowstone, for example, that's ready to blow is a bit of an exaggeration. Most of the crust beneath that and many other supervolcanoes is solid, with little pockets of magma making up a total of about 9% of the structure. Estimates vary but it's generally thought that the magma volume would have to reach at least 50% before we're in danger of any impromptu fireworks.

Much like an asteroid impact, no one is denying that a supervolcanic eruption would be spectacularly bad news but, also like the asteroid threat, this means that there are lots of very clever people keeping a very close eye on the situation. By carefully tracking the activity beneath the Earth's crust, we could have years of warning before the explosion actually came.

So, yes, it would be pretty bad for Yellowstone, or any other supervolcano, to blow its top but it's not going to catch us unawares.