10 apocalyptic scenarios, but you fail to consider probabilities. Risk is the product of consequence and probability. The world is a big and varied place; the chances of most of the above actually coming to pass are very small.
The problem is not just complacency. The history of a population of six billion has vast inertia, even if those steering it only number in the thousands. Replacing those in power would not solve anything, since the cycle would eventually begin again. It'd buy time, perhaps, but changing leadership by force has unpredictable consequences on the rest of the population and changing it by vote requires a majority (which is how the current guys got into power, at least in democracies).
The other approach is to start at the bottom and aim for a global change in how humans think. With the Internet this is possible, but still requires a group with appreciable historic inertia to exert a lot of effort. Six billion minds need to be changed. Doing that fast enough would require millions to cooperate. Cooperation on that scale is rarely seen outside of wartime, which says a lot about people, really.