Actually, the president of SONJ predicted reserves of oil would run out in 15 years. This was in 1923.:smack:
Well I think it is the OP who is confused, or at least not clear enough. He’s talking about “crude oil used in the making of transportation fuels on a mass scale”. Is 1/10th of today’s production still “mass scale”? I’d say it is. Less people will drive, and they’ll mostly drive very efficient vehicles. I think it will be forced by supply constraints playing out over 100 years and the economics will follow on that.
Beyond that, I can imagine a situation where oil is too expensive for general use, but some corporation owns land with shale underneath and thinks it would be worth it to frack for its own, personal supply. Kind of a Mad Max scenario and a candidate for fulfilling ‘depleted’.
I don’t think it will ever be depleted, but not for the reason in your poll. Necessity will force the adoption of alternatives before all oil is used up.
Hydrogen is probably the most likely alternative at this time, unless they can produce algae based oil in sufficient quantities.
Oil is not just necessary for motive power- it is used to make just about everything we use these days.
BTW when I was at school we were told oil would be used up in 20 years, and that was a lot longer than 20 years ago!