The drastic "End" to human civilization as we know it will happen. How? Famine, pandemic disease, depletion of resources, terrorist attack (dirty-radioactive/biological bomb), drastic climate shift- start of next ice age, direct hit by comet/asteroid= life extinction event,polar magnetic field reversal=no protection from gamma/solar UV radiation for 200 yrs, super volcano erupts(Yellowstone USA, others), for starters. All of these are natural events that have a high probability of occuring in the next 1- 1000 years. Any of these events could mean the end of global civilized life as we know it.