Your car goes 3.5 m.p.h.?

John Michael Greer, the Grand Archdruid of the Ancient Order of Druids in America, publishes a weekly post at his site, The Archdruid Report. Greer is a much deeper thinker than I, particularly with respect to the interplay between past, present, and future. He describes his area of thought as the "history of ideas," and his grasp is broad and deep, regardless of whether you agree with him or not. A steady diet of The Archdruid Report would certainly depress me, though Greer does not strike me as depressed. He's certainly "cocksure" though, in the sense of certainty of his conclusions.

Nevertheless, I read his posts from time to time and invariably find them thought provoking. Today, in reading his post entitled "Peak Meaninglessness," I found him citing Ivan Illich from "Energy and Equity" (available as a free pdf download) contending that

"Illich’s discussion focused on automobiles; he pointed out that if you take the distance traveled by the average American auto in a year, and divide that by the total amount of time spent earning the money to pay for the auto, fuel, maintenance, insurance, etc., plus all the other time eaten up by tending to the auto in various ways, the average American car goes about 3.5 miles an hour: about the same pace, that is, that an ordinary human being can walk."

Is it true? If it is, does it have any meaning? Since, for reasons that should be obvious, I'm not interested in using my personal financial details for such a calculation, I'll posit an American household earning the median income of $52,000/year. The household consists of a husband, wife, and two children. The husband works 2,000 hours/year and earns $40,000 and the wife works 1,000 hours/year and earns $12,000. As an aside, this family doesn't live in Southern California. The average hourly earning is thus about $17.30/hour. Of course they'll only bring home, at best, perhaps $14/hour after taxes.

I'll assume two cars traveling a total of 26,000 miles per year with an average of 1.2 people in the vehicle for 31,200 passenger miles per year. The vehicles average 25 m.p.g. and gas costs $3.80/gallon, so they spend about $3,950/year on gas.

One car is a relatively new (say, two years old and purchased for $29,000 on a five year loan at 5% API with 20% down) five passenger sedan. The monthly payment is around $440, or $5,280/year. The other is a minivan on a three year lease with monthly $3,000 at signing and $300/month lease payments, or $3,600/year. They paid $8,800 up front to have the vehicles but, since interest rates on money market investments are close to zero, the opportunity costs are quite low, so I'll use the up front cash divided by the respective term in months. This adds about $2,160 to the annual total. The total to finance the cars is $11,040/year.

They take the vehicles in for scheduled maintenance a total of eight times per year and spend $300 each time (sometimes less, sometimes more depending on the service required by the schedule). The total is $2,400/year.

This family has decent driving records and no teen drivers so the annual insurance premium is about $1,500.

The grand total (leaving out car washes, aftermarket accessories, etc.) of annual expenses is $18,890. Wow, that IS a lot of money! Now, this $18,890 takes 1,350 hours (45% of their working hours) of this family's time to earn. So the final result is in: 26,000 miles/1,350 hours is about 19.25 miles per hour. This is about 5.5 times faster than Illich's estimate. So the answer to the first question, "is it true?", appears to be "no."

The second question is not so easily answered. The entirety of this family's lifestyle revolves around the vehicles. Without them, it's unlikely (though certainly not impossible) that the $52,000 would be earned. And, while a vehicle undoubtedly constrains them financially, it also enables them to do many things that would otherwise be difficult or impossible. A vehicle-free lifestyle is certainly possible (I've lived such a lifestyle at various times and for various reasons), but this family has decided that the tradeoff is worth it. I WILL say, however, that they'd have been much better off with different vehicle choices. Another way of saying this is that I believe I've made assumptions that are generous to Illich's claim as repeated by Greer.

Eating energy

In round numbers, there are 7 billion people eating on planet Earth each day. It's pretty clear that my diet here in Southern California is very different from that of a subsistence farmer in Namibia or a subsistence fisherman (or fisherperson) in Madagascar. It's also true that, as a fully grown adult of age 60, I probably consume more calories than my one year old grandson. But I estimate that my daily intake is on the order of 2000 kilocalories per day of food energy and I don't think that long term survival for an adult is possible on much under 1000 kilocalories per day. Of course, not all humans are adults and estimates of population in each quinennial group are available from the UN. Still, for rough estimates, 7 billion people consuming 1000 kilocalories per day will work.

Thus, in raw terms, this equates to humanity ingesting food energy at the rate of 7*10^12 kilocalories per day or about 10 "quads"/year (for some reason, lots of analysis of world primary energy is done in quads, where a quad is 10^15 or a quadrillion btu(a so-called "short scale" quadrillion)). Of course, the amount of chemical energy in our food as measured by bomb calorimetry exceeds this number since we cannot oxidize 100% of the mass that we ingest, the unburned residue leaves us in ... various ways... ahem. And we certainly don't ingest 100% of the food plants we eat. Further, many of us eat the meat of animals who have ingested the plants, or even the animals who have eaten the animals who...

But, in my simplistic model world, I'm going to estimate that 20% of the mass of a food plant is edible, that we burn 50% of it for energy, that meat represents 20% of the kilocalories consumed by humanity, and that the "hit" on losses due to an animal intermediary is the square of the losses inherent in eating plants directly. Thus, 10*0.8*P+100*0.2*P=C where P is the available kilocalories of "primary burnable energy" ("PBE")and C is kilocalories ingested as metabolizable food energy. So we have that 28 kilocalories of PBE are required for every dietary kilocalorie in this model.

So, we're now talking about 28*10 or 280 quads per year in photosynthetically created PBE. Depending on the plant species involved, the efficiency of using solar energy to convert carbon dioxide and water to biomass is in the range of 3% to 6%. I'll use 5% since it makes the arithmetic easy, and thus 5,600 quads of solar energy per year are needed to feed us. Let's move to SI units: the 5,600 quads are 5.9*10^9 terajoules and 5,600 quads/year are 187 terawatts.

This energy comes, of course, from the sun. There are approximately 14 million km^2 or 14*10^12 m^2 of arable land on our planet so, on average, each arable square meter must be responsible for converting (5.9*10^9 terajoules)/(14*10^12m^2)=422 megajoules/year or an average rate of 13.4 watts of incoming solar energy into ingested food energy.

And, as we see in the graphic at right, this is something like an order of magnitude away from the total incoming energy absorbed by the surface of the Earth. While I've looked at other articles that come to different conclusions about solar energy embodied in our food, I'd be shocked if I were off by an order of magnitude. The lesson? There's not a lot of spare capacity in our system for squandering our biota's ability to feed us.

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Rob's aphorisms

There have been a few seemingly simplistic or tautological things that I've incorporated into various situation analyses.

1. If something's wrong, something's wrong. This is a conclusion reached jointly by my closest friend Dr. Captain Right Reverend Frank Hanna (Frank is second from right in this photo from 2000 of the Northern Arizona University Department of Geography and Public Planning), may he rest in peace. It came to us during flying together but has wide applicability in business, at home, and elsewhere. For example, I'm flying at 11,000 feet density altitude, power is at 27" manifold pressure and 2,400 r.p.m. I usually get 142 knots indicated airspeed in this situation, today it's 132. "Huh, oh well, la de da." 10 minutes later: "Oh $*)^%*, I forgot to put the flaps up." If something's wrong, something's wrong.
2. If it did, then it can. Frank was a professor of geology and took students on field trips, sometimes to map geological features. Students would look at, measure, and map some feature, scrunch their brow and say "but can it do that"? Answer: If it did, then it can.
3.  If they are, then they do. I got my start in the business I'm now in via performing inspection of various facets of building construction. I'd see some very shady things apparently involving various quid pro quos (quids pro quo?) between contractors and construction managers (who ostensibly represent the interests of the owner of the development). A newer inspector would say "Do they really do that"? If they are, then they do.
4. Everything is dramatically more difficult and complex than you thought it would be, even when you allow for things being dramatically more difficult and complex than you thought they would be. This applies to everything from installing drywall or toilets to welding to applying conservation of momentum to a dynamics problem. Self explanatory.

Now, along with always assuring that you're wearing clean underwear (about which I wrote a song decades ago, motivated by a friend who said she couldn't bring herself to commit suicide because she didn't want to be found in her unkempt apartment), applying these should come close to assuring a smooth sail through life's various meanders.

You're welcome.