You are thinking hundreds to thousands of years, whereas I am thinking that techno-man will be all but wiped out at the next ice age in a few 10,000's years. Will your iron ore stocks be enough to last Austria for 10,000 years?
Uhm ok, lets get this clear. An ice age does not happen over night. It takes a looong time for it to come along. Enough time for us humans to react by e.g. using geo/climate engineering.
Plus, even an ice age would not simply whipe out the memory of the entire human knowledge. It is a ridiculous assumption!
Even a most dramatic impact of an asteroid would not achieve that, unless it is an extinction event. That would maybe be the exception, but even then, it seems likely that at least some humans with some knowledge and skills would survive in a way that would allow them to pass on the knowledge for a few generations.
Austrias iron reserves are of course small. As I said, we barely have any resources on our own, thanks to WW1 and the shameful peace of St. Germain. But anyway, we still have reserves that would allow us to continue on a lower level, even in the event hat ALL other resources dry out. Not for thousands of years of course. But for a few decades.
That is enough time to come up with something else.
If energy was almost free, there would be plenty of ways to do that. You could dig deeper, much deeper, you could mine asteroids and so on...
Free energy solves a lot of problems, especially with resource gathering.
Heck, as you know the core of our planet is mostly iron...
It is a lovely idea, but is not facing down the reality. It is quite evident that those stocks would dwindle to uselessness at the current high rates of material consumption and current low rates of advances to interstellar exploration.
Chris, the topic is "with free energy". With free energy, provided it is useable for space propulsion, we can easily, easily improve our space traveling. We wont need interstellar either. For now, we would barely need interplanetary. Maybe in a few thousand years, we would need interstellar, but that is a problem for future generations to solve. I always say that we should plan for millenia ahead, but some developments require the development of other things first. Lets begin with finding an energy source for our interstellar space ships. Once we have that, we can think about a propulsion system to power with that energy source...
Right now the energy source is the most important thing, as it solves other problems as well.
Modern techno-man will cause his civilisation to die out in the same way as most before him - by complacency that everything will work out OK because we are so ascendant now and it is inconceivable that the Roman Empire could end.
That is a ridiculous assumption. Yes, western civilization might come to an end. Most likely it will be taken over by others that have higher fertility rates. A slow process, but as it seems, unavoidable. However, whoever will take over from us, will use most of our knowledge and keep building on that. Just like the "barbarians" that took over Rome. Yes a lot was lost in the early middle ages, but not everything and those were very different times, with little knowledge.
It is inconceivable to me that when millions of people know how to build a simple gasoline engine, this knowledge could be lost. Since just as many people know how to make alcohol that could act as a fuel, it seems impossible to me that this knowledge could just disappear.
Steam engines are even simpler. Heck even I would be able to build a simple one.