Re: Caveat
Most easily accessible coal, iron ore and petroleum deposits are pretty much tapped our. After a couple of generations of struggling to survive, would the knowledge be there to start again?
Who needs ore? The surface of the planet is littered with vast quantities of pre-smelted metals created by this civilization and nothing is going to bury them again on less than tectonic timescales. As for fossil fuels, they weren't a significant factor in human development until the industrial revolution.
You could meet all human global power requirements via hydro-electricity alone, even at contemporary consumption levels, if you dial back population numbers by a couple of centuries (about 1 billion in 1800). What no-one likes to discuss is that anthropogenic climate change is just a variation on Malthusian Catastrophe - it's essentially a demographic problem.
Biting the hand that feeds IT
