The topic of mining asteroids for valuable resources has come up recently — one senior man in a mining corporation given publicity on the Internet suggesting that we might find an asteroid with high concentrations of platinum. An economist has replied that if a lot of platinum were available then it would simply become very cheap. It’s water we really need on earth. I replied as follows:
Humans desperately need water because its dire shortage happens to be one of the ways by which the world economy finds its automatic level of activity — that is, the law of least effort (or maximum thermodynamic efficiency, if you like). Because the ultimate size of a stabilised world economy is much more critically dependent on incoming energy — solar plus fossilised solar — then the present price of energy suggests that the world economy is probably heading downwards rather than upwards towards stabilisation. Mining ex-earth for anything except energy — even water — would not make the slightest difference to the size of the ultimate stabilised economy.