Had the global financial system been allowed to cross a critical threshold in 2008, its collapse would have triggered cascading failure across human society. Only a global bailout amounting to trillions of dollars pushed it back into a safer state. Even before hysteresis occurred, far more energy (or money) was needed to stop the collapse than was needed (via the US subprime crisis) to cause it. Mass extinction events appear to be another example of contagious collapse. When one ecosystem or Earth system topples, it can pull down the systems that interact with it.12 While
