Comment by est31 | Hacker News Reader

Comment by est31 | Hacker News Reader

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(d) their previous activities have rendered it way harder to rebuild a technological society

There used to be iron deposits etc. on the surface. They were recovered by pre-industrial societies. Now we are digging deeper and deeper for resources, but once we lose that ability, it's possible we won't be able to regain it.

What do you do once the nuclear power plant's core has melted, the mine is full of water, and there is nobody around who knows what these things are even there for because all the people who did died years ago of old age. You can't read it up either once we've moved our stored knowledge from paper to machines in what the ancient texts refer to as the mythical "US-EAST-2 region".

Humans have deposited a lot of iron and other useful elements on the surface for the next civilization to start with though.

It's less of an issue with recraftable materials (like iron) and moreso with one-way ones (like petroleum, fissionable uranium isotopes, helium, or some plastics).

Of those, it feels like the only irreconcilable one is scale: e.g. something you need so much of, repeatedly, that no less-efficient substitute is viable.

And of those, geologically-created, carbon-based energy sources (coal, oil) are the primaries that come to mind.

(Also, nitrogen, but I imagine the Haber–Bosch process would survive)

Where did all that iron that we mined run off to? Is it not on the surface anymore?

1. it might be covered in sediments requiring expensive movement for little gain (and how do you know where the iron was/is?) and 2. the structures that don't get covered rust away and turn into dust that erosion distributes over large areas. Post apocalyptic societies will be able to salvage iron here and there for a long time, but will it be enough to cover our planet with railways and kick off a new industrial revolution?

Also, the iron was only an example. Coal and other fossil fuels we can only burn once, then they are gone.

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