Not to seem like a smartass, or a jackass, or any kind of ass for that matter, but this seems kind of obvious from the get-go. Bigger mechanisms (machines, programs, societies) need more energy/fuel to keep them going. Insufficient energy results in something similar to the results of the Great Starvation Experiment, and too much results in a fireworks frenzy of expansion and growth (Sort of like that monster at the end of Evolution - in fact, the aliens in that movie are a perfect example of this)

As for the inevitable collapse of society, i'm not so sure about that. Sure, The US, China, and the world as we know it may end/change drastically, but that's usually what happens as we transition into a more advanced, larger society. Which isn't to say that all elements of the previous societies are destroyed. They're often incorporated into the newer ones, resulting in a never ending cooking pot of mashed up societies and ideas. We shouldn't have too much to worry qabout in the future - The US, being the biggest example of conflicting societies and ideas chunked together, is alive and kicking after more than 200 years of internal wear, tear, and dissent; and if that can stick together, then modern society for Earth as a whole can.