We have exhausted the "low hanging fruit" of energy. Or not?

Recently, Tyler Cowen wrote about how the US has pretty much gathered all the low hanging fruit of economic growth and development and that we are doomed from now on, unless we adopted something along the lines of a libertarian manifesto.  Reviewing Cowen's e-book, Timothy Noah wrote in Slate:

Cowen's core message is: Get used to economic stagnation, or what he calls "the new normal." It's a weird conservative echo of liberalism's era-of-limits gospel from the 1970s, articulated by the Club of Rome and other groups, the chief difference being that liberals used economic pessimism to sell wise environmental stewardship while Cowen is using it to sell complacency about the fate of the middle class.

The WSJ did not do him a favor, which they thought they were doing, when writing:

His arguments aren’t perfect, and “low-hanging fruit” doesn’t quite have the catchiness of “The World is Flat,” but in terms of framing the dialogue Tyler Cowen may very well turn out to be this decade’s Thomas Friedman. 

Tyler Cowen is infinitely smarter than a Thomas Friedman. What an insult to him!

Anyway, my point is that it was Cowen's "low hanging fruit" thesis that I was reminded of as I was reading in the Scientific American this essay, which in print is titled "The true cost of fossil fuels."  The core argument involves "energy return on investment (EROI)" which is a measure that is a ratio of how much energy is returned compared to the investment.  Given that we dig for fossil fuels, it is an inversion of "low hanging fruit" in the sense that the easier it is to extract the fuel, the higher the return on it.

You need a subscription to get to the detailed charts.  And I have no patience to provide here photos of those charts.  But, the inventor of this metric explains the logic in the interview with the magazine:

What happens when the EROI gets too low? What’s achievable at different EROIs? If you've got an EROI of 1.1:1, you can pump the oil out of the ground and look at it. If you've got 1.2:1, you can refine it and look at it. At 1.3:1, you can move it to where you want it and look at it. We looked at the minimum EROI you need to drive a truck, and you need at least 3:1 at the wellhead. Now, if you want to put anything in the truck, like grain, you need to have an EROI of 5:1. And that includes the depreciation for the truck. But if you want to include the depreciation for the truck driver and the oil worker and the farmer, then you've got to support the families. And then you need an EROI of 7:1. And if you want education, you need 8:1 or 9:1. And if you want health care, you need 10:1 or 11:1.

Tyler Cowen says that we have exhausted the low hanging fruit with respect to education and healthcare.  EROI now tells us that these two will become even more expensive. The only thing good about the EROI is that yet again is a confirmation that the gazillions that go into subsidizing ethanol are wasted.

Sounds tempting to conclude, therefore, this will be the new normal and that we better get used to it.  If one is born into the middle or lower classes, well, you might as well move to Montana, build yourself a log cabin, and live your life hunting bears and fly fishing.

Except, the same issue of the Scientific American has an interesting piece in its regular feature of highlighting an article or theme from past years.  And, what was featured this time?  Well, it is from one hundred years ago, from April 1913:

Yep, a hundred years ago, the worry was about energy sources once we exhausted the coal mines:

Long before we took stock of our fuel supply and found that we must husband what little we have left, scientific dreamers wondered whether natural forces could not in some way be utilized. Already we are making extensive use of water power, or 'white coal' as it is called. The tide has yielded us some power and so have the waves.

Note there what is missing: petroleum, natural gas, and nuclear power.  In 1913, humans hadn't even figured out the proton and the neutron. Neutrinos weren't probably even in the collective human imagination.

I do not mean to suggest that science and technology will lead us out of the stagnation and that we can all rest easy until those nerds in the labs figure things out for us.  But, come on, sky-is-falling?  Check with Thomas Malthus about how his sky-is-falling claim worked out!  I suppose we have been worrying about the future ever since the proto-human stood up on two legs and made the other two as "hands" and sat posing as Rodin's Thinker.  We have evolved to worry, which is good--the worrying has led us to innovate.  Worry away :)