What is an extinction level event?
An extinction level event (ELE) is an event where the majority of life on Earth becomes extinct, usually caused by a single catastrophic event or series of events. This is opposed to normal extinctions of just a single species, which happen all the time in the wild at a background extinction rate. Things that cause extinction level events include super-volcanoes and climate change, which are events suspected to have happened in the past on several occasions as noted below. The most spectacular events we can imagine are asteroid impacts which have been popularized in the late 1990s by the movies "Deep Impact" and "Armageddon" and later, in a slightly different fashion, by spectacular but equally as flawed movies such as "The Day After Tomorrow" or "2012". There are also TV shows such as the highly popular "The Walking Dead" or "Z-Nation" depicting mass pandemics albeit of the zombie kind. It's hard to not see movies and TV shows that wander through post-apocalyptic and dystopian worlds.
Why should I care?
Hopefully, you don't have to; these are not every day events and some, such as the type of asteroid impact capable of inflicting an extinction level event are few and far between. However, that doesn't mean something won't happen and, in fact, is, eventually, very likely to happen. For instance, there are thousands of small earthquakes that take place every day around the world. Occasionally, a large quake happens and we have no means of pre-determining any of them other than to say "I live near an earthquake zone so I will feel one at some point".
On top of which, if we know that at some point, one of these events will take place, shouldn't we plan for it? Take some reasonable precautions? For instance, if you live in a hurricane zone you take steps to try to ensure that your property is protected. It isn't a leap to take some simple steps that could make the difference between life and death when an extinction level event does occur.
What can I do about it?
As an individual you could do simple things like have an escape pack ready to go, keep reasonable supplies of food and water readily available, make a plan to escape to a safer area and so on. You and your family would have a fighting chance of surviving by taking some simple steps now.
Has it happened before?
The fossil record, at present, appears to indicate that there have been a number of extinction level events and those are discussed and described under the menu option "ELE" above.
Will it really destroy the earth?
Most of the extinction level events that we discuss here do not have the ability to destroy the planet and by that we mean render the planet into a state where it either no longer exists or will never be capable of harboring life again. That would take an event like the Sun dying, or the Moon somehow falling out of it's orbit and colliding with the Earth. Events that could, potentially, render the planet uninhabitable to any form of life might be a super-nova erupting close by and bathing the earth in deadly gamma rays. That is unlikely, though, as, to the best of our knowledge, there are no stars close enough that can cause that level of damage that are likely to go super nova for millions of years, if at all.
So, no, it is very unlikely that a disaster will befall the planet that would physically destroy it. Life may vanish for a while but the fossil and geological records indicate that life, of some sort, will flourish again.
