The miracle of photosynthesis, the plant-and-animal cycle, is a closed cycle. You have opened it -- and your lifeblood runs downhill....
- Robert Heinlein
I'm in the middle of reading Michael Pollan's excellent book, The Omnivore's Dilemma. If you're a public radio junkie like me, you've probably heard more than one interview with him. The relevance of the subject matter -- how all of us in the United States manage to feed ourselves -- and the engaging and lucid way he makes his points make him one of my favorite guests to listen to.
I read some interesting things this morning:
The fertility of the earth is limited in large part by the amount of fixed nitrogen in the soil -- that is, the amount of nitrogen that has been converted from its inert form in the atmosphere into more reactive forms that are useful for life. Only a few organisms are able to fix nitrogen: so-called "nitrogen-fixing" bacteria (clever name) that live among the roots of some plants, such as legumes. The amount of nitrogen these bacteria can fix, by limiting the number of plants that can grow on a given plot of land, essentially limits the size of the entire biosphere that subsists on that land.
This is a problem for a species, like ours, with unlimited ambition and for a society, like ours, that would rather have its people compete in industries other than farming, so we have improved upon nature with chemistry. The Haber-Bosch process, developed in the early 20th century for the dual purposes of farming and chemical warfare, fixes nitrogen chemically using fossil fuels -- in particular natural gas -- as inputs. The resulting chemical fertilizers allow farmland to support many times the number of plants that its native fertility could support. How well this process works is testified to by the fact that most of the nitrogen in your body and mine was fixed, not by soil bacteria, but by the Haber-Bosch process. Indeed, somewhere between 30% and 40% of the human beings alive today would not be but for our ability to increase fertility in this way.
(An interesting and sad corollary: farmland that used to produce corn before the era of chemical fertilizers has, with their aid, increased its yield tenfold. However, where it used to produce two calories of food for each calorie invested in it, it now requires more than a calorie of fossil fuel to produce a single calorie of food. We are breathing methane, drinking oil, and eating coal, my friends.)
...which set my gears spinning:
Of course we have not actually increased the fertility of our land at all -- not any more than a TiVo increases the number of shows on television. We have simply time-shifted forward the nutrition our food crops require by millions of years. As fossil fertilizers become less available and more expensive, we are liable to discover that we need a good deal more farmland and a good deal more farmers -- and that there are too many of us by half.
All of this exposes a rather large but apparently thus-far-unnoticed problem with the fossil fuel industry -- indeed, with almost all extractive industries. They are based on an economically unsound practice: liquidating capital and calling it income. If I possess a stockpile of gold bars, each worth $100, and sell one of those bars to you for $100, only a fool would claim that I have made myself $100 richer. But if I own $100 worth of oil under the ground, and I pump it up and sell it to you for $100, I will immediately be acclaimed as a baron of the most profitable business ever.
I may have shared this analogy before, but here goes:
Suppose I have before me a basin of water. This water is replenished at a rate of one tall refreshing glass every day. At the same time, I dip my glass into this basin every day and take out one glass to drink. But now I get to thinking (never a good idea), and I approach several of my friends. "If you will invest your money with me," I say, "I will be able to buy a second glass, and will be able to dip twice as much water, which I will share with you." They do, I do, and we all enjoy the extra water very much. But of course there's no more water than there ever was; we're just depleting our stockpile twice as fast as it's being replenished. We might get away with this for a while, but eventually we will learn the hard way that, as Heinlein also wrote, There Ain't No Such Thing As A Free Lunch.
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