[Hoodat]

Something similar to what happened when whale oil ran out, I suppose.

But whale oil never did run out, and neither will our current petroleum supply.

[GonzoGOP]

But whale oil never did run out, and neither will our current petroleum supply.

No but between 1860 - 1880 whales got scarce enough that it became cheaper to refine the black goop they found in Pennsylvania then send ship all over the world to find whales. The substitutes already exist, see my post on TDP, so if/when supplies run down the substitutes will kick in. you can't run out of something you can grow, reuse and make from garbage.