The reason I called it decaying earth was because I played a video game that was set in the future, past humanities almost extinction.  The world was scattered with pieces of our decayed civilization, nature reclaimed what we conquered, and the scattered pieces of humanity was broken into tribes and mostly feared us and the greed that brought down our world.  It's eye opening to think about how our memory won't be there in a thousand years, let alone a hundred, and we need to create and build something that may last.