History Repeats Itself
In the history of Earth, there have been five mass extinctions in which at least half the species on the planet disappeared. Scientists believe the extinctions were brought on by natural disasters -- massive volcanic eruptions, rapid climate changes and meteors hitting Earth.
Today, scientists say we are in the middle of a "sixth extinction" -- and for the first time, it's being caused by one species -- us. It seems inconceivable that we could do so much damage to our planet that we actually cause society as we know it to collapse. But historical precedent shows that it is, in fact, a very real possibility.
"Every society that collapsed thought it couldn't happen to them," says Joseph Tainter, an expert in anthropology and societal collapse. "The Roman Empire thought it couldn't happen. The Maya civilization thought it couldn't happen. Everyone thought it couldn't happen to them. But it did."
These populations grew too much and exhausted their resources -- and their climate suddenly changed. People were forced to fight each other for what little was left or face starvation. Entire societies broke down.
"Civilizations in the past have lost the fight," says climatologist Heidi Cullen. "They have collapsed as a result of the inability to deal with several different events going on at once. I think the takeaway is that honestly, we are not that special."