And as you know, part of the tenets of biophysical economics is measuring our natural resource endowments in natural resource terms, themselves. For example, Energy Return On Investment (EROI) is how much energy it takes to get one unit of energy in our society. And 70, 80 years ago, we would invest one barrel of energy to get out a hundred barrels of oil, and that 100:1 ratio declined to 30:1 in the 1970’s, and it was around 10:1 in the year 2000, and the EIA stopped producing data on how much energy it takes to get energy. So we can kind of interpolate it now, but it’s clearly under ten in single digits.
And you eventually get to a point, even if oil is $100,000 dollars a barrel, or $1 million dollars a barrel, if it takes one barrel of oil to get out barrel of oil, you’re kind of out of gas at that point.