Human civilization feels so much more fragile to me since I realized how much we owe our technological progress to the accumulated effects of biological processes over geological timescales. Fossil fuels seem like the most obvious part of this story. If we had to start over "from scratch", would it even be possible? Or have we already so thoroughly exhausted the low-hanging energy stores that a second "industrial revolution" would be effectively impossible if our present civilization collapsed deeply enough?
I wasn't aware that concentrated stores of iron are also an important part of this story!
> Or have we already so thoroughly exhausted the low-hanging energy stores that a second "industrial revolution" would be effectively impossible if our present civilization collapsed deeply enough?
There's plenty of coal left, and we will likely never exploit it, because solar is getting so cheap.
Also, despite long prophecies, peak oil never arrived either. So it doesn't look like we are running out of that stuff.