currency when you boil finances down to the simplest possible model there's only unit of currency: a person's labor. you can leverage that labor by drilling oil and adding the work the oil can do to the labor pool. oil is an amazing thing. a single barrel of oil is worth 15 /years/ of labor. each day we produce some 500 billion man-days worth of oil. people produce some insignificant 2 billion man-days of labor. it costs some 25 billion man-days to produce that oil. and yeah, i'm starting to pull numbers out of my backside for the purposes of illustration. anywho, after the math clears we're left with some 80 man-days of labor per person. that labor is spent on necessities and luxuries. let's call it half and half. and yeah that's a guess. but it's not far off. it's really impressive how much energy it takes to feed everyone. anywho, fast forward 50 years. at current growth rates the population doubles and oil demand quadruples. now things look more like this: 2 trillion man-days oil produced per day and 4 billion man-days from humans. but that oil now costs some 500 billion man-days. resulting in 125 man-days per person. nice! an obvious win, right? well maybe. depends on how much it costs to feed everyone. if the energy cost of necessities triples, the amount you have available for luxuries plummets from 40 to 5. which is fine as long as the technology factor boosts luxury production by more than 8x. heh. my grandkids are gonna be so poor.  ¶ 8:00 AM