Rereading Margaret Atwood's Oryx and Crake, I noticed an off-hand comment of Crake I hadn't before. There is no second chance for civilization. History is full of stories of empires rising and falling and rising again. So it seems natural to assume that if civilization collapses, people will eventually pull themselves back together and rebuild. Probably faster than last time, because of the residual knowledge preserved in writings and artifacts, and maybe in lore. But there's a key problem.
All the easily accessible deposits of coal, oil, and gas have been used. There is more in the ground. Some say a lot more, some say not much more, but it doesn't matter. At this point, it takes an advanced technical society to get it. No one is going to invent hydrofracking if they don't already have sophisticated technology built on ample energy supplies. You don't start drilling for oil on the ocean bottom. If you need to move a mountain to get at a coal bed, you need earth-moving machinery.
Atwood posits that this is even true for metals. Sources of iron and copper are no longer sitting on the surface, easily found. In order to sink a mine five hundred yards into the earth, you need to already have metal tools. There will be salvage metal available, of course. That may be enough to get metal-working going again. But I don't see any way around the energy bottleneck.
The mythology is wrong. Empires rise and fall and rise again. Civilization rises, endures for a time, and then passes away.
Humans have trod this earth for 50-150,000 years (counting from "Behavioral Modernity"). Civilization has only existed for 5,000 of those years. For the first 2-4,000 years, it was an oddity, practiced only in certain regions where the available resources were ideal. It's only in the last 1,000-1,500 years that civilization has been extensive around the globe.
Enjoy it while we've got it. It may never come again.
