I'm not sure how many historians there are here in the comment section, but it seems like to me that the modern world, and the United States in particular, have set in motion a chain of events that may lead to a total "systems collapse," in the very near future. "Systems collapse" is what happened to the western Roman empire in the 5th century, it's what happened to the Soviet Union in the 1990's, and it may happen to the United States and many other industrialized nations in the next few decades too. We've built a world today that's utterly dependent upon trade, both intentional and domestic. And this trade is absolutely essential for keeping international conflicts from springing up, it keeps our economies rolling, people employed, and it's a huge web that effects almost square inch of this planet today. And since literally ALL of that trade network relies upon petroleum powered transportation equipment ...well, you see where this is going right? We currently have no renewable way of powering the transportation infrastructure that this world relies upon everyday, and we've only got a few more decades to figure that problem out or we're fucked.
A similar systems collapse event happened back during the end of the Bronze Age, and is known today as "The Late Bronze Age Collapse." In a period of only about ten year's time, TEN YEARS, every single kingdom located in modern-day Egypt, Greece, Cyprus, Crete, Anatolia (Turkey), Israel, and Syria was destroyed. Their societies all relied upon using bronze farming implements, like hoes and horse-drawn plows, to be able to feed their populations at the time. And when the bronze, a mixture of copper and the extremely rare element tin, started to be depleted to such an extent that bronze farming equipment could no longed be replaced affordably enough, reliably enough, or rapidly enough, the entire civilization, along with all of their trade networks, collapsed before they could find a replacement for their bronze. And since today every single person in the modern world relies almost solely upon petroleum powered agricultural equipment to keep us affordably clothed and fed, we too may in for a systems collapse event like the ones suffered by so many ancient nations that came before us.