EROI, or Energy return on investment, as measured by the amount of energy attained over the amount of energy consumed in the attainment, is going down
. In other words it is taking more and more energy (oil) to extract and refine energy (oil) from the earth.
In the 1930's the ratio was roughly 100:1. It took a barrel of oil worth of energy to extract 100 barrels of oil. In the 1970's that ratio was down to 30:1 and by the turn of the century it was all the way down to 11:1.
Anyone who doesn't believe that these numbers indicate an increasing concern for us (and in the very near-term, to boot) is fooling themselves and doing no favour to the rest of us.