I'm not an anti-natalist because I don't accept the central plank in their platform that "having children under any and all circumstances guarantees continued suffering". I have no desire to see our species vanish.
By "resting place" I merely meant that you have gone as far as you can in the logic of promoting H production at sea by solar power. Once you've proved that 2+2=4, people have to either accept the fact or ignore it. There are quite a few examples of 2+2=4 that people seem quite capable of ignoring. Just a simple example here:
The city of Minneapolis, where I live, collects trash, recyclable material (single stream) and compostable material. All that is a plus. We have found that it is very difficult, apparently, for many people to figure out what the difference is between trash, recyclable, and compostable. Signs with words, signs with pictures, signs with actual examples, someone standing behind the bins telling people where the stuff goes -- none of this seems to work with a certain percentage of the population. I think it should be obvious even to morons that a bin with potato peelings, left-over food from plates, moldy bread, carrot tops, spoiled oranges, etc. IS NOT the right bin for plastic cups and aluminum cans. None the less, some otherwise not apparently too-stupid-to-breathe people still don't get it.
If we can't get people to figure out the difference between rotten oranges and aluminum cans...
Seven tenths of the earth's surface is still as rich in metals as when the earth was new. — karl stone
I would imagine that better than 99.9% of the metals that were ever in the earth are still on earth--somewhere. That doesn't mean that it is even remotely possible (in the imaginable future) to get at these metals for a bearable cost.
How will we overcome the problem of metals becoming harder to find in large, accessible quantities?
Take iron, for example. Iron wasn't extruded by magma or volcanoes. 2 billion years ago iron was mostly suspended in water. As cyanobacteria produced oxygen, the O combined with Fe producing an oxide which settled on the sea floors and, in certain places, was concentrated. Other metal deposits were formed by other geological processes. Other metal deposits are formed more directly by geologic activity, plus precipitation and concentration processes. Large deposits just don't occur everywhere.
True, there may be tiny bits of gold, tin, zinc, silver, rare earths, aluminum, nickel, and so on scattered around the globe, but if they were not concentrated a billion years or two ago (or more) then the chances of us getting our hot little hands on lots of it are exceeding small. We aren't going to run out of iron or aluminum tomorrow, but the reachable supply is by no stretch of the imagination inexhaustible.
Take Uranium
as an example of a metal with a limited supply: the available unmined reserves of uranium are reported in "millions of
pounds" not millions of tons. Were the world to use nuclear fuel heavily, we would find the supply far short of needs.