[alecifel]

It's a common line amongst us "peakers" that everyone is effectively a slaveowner when it comes to fossil fuels. But few have been mathematically inclined to sketch out what kind of numbers those really are.

Would you like to see an exercise in Friday afternoon boredom and a demonstration in unsustainability?

1. How many man hours are in our GDP?

US oil consumption = 26 mpd
Annual oil consumption = 9,490 million barrels
Man-hours per barrel = 16,800 (400 x 42)
Total petroleum manhour equivalents = 159,432,000,000,000 (that's 159 Trillion, with a "T")
divided by 40-hour workweeks and then divide that result by an assumed national population of 285 million:

Each man, woman, and child in the US has the equal of 13,985 slaves.

(Somehow the math doesn't sound right, but I've checked it thrice.)

Conversely, that means if the oil was cut off completely, we'd be able to produce only 1/13985th of our current output with manual labor.

This does not include any energy other than crude oil. Those are a whole other gang of slaves.

2) Corn?

I did a little experiment the other day. I planted a test plot 10x10 feet with corn using only hand methods. Hoeing, raking, and preparing the soil, planting, and then figuring how long it would take to weed, fertilise, harvest and shuck it, I came up with about 6-3/4 hours per 10x10 foot area. Then I said, economy of scale would give me a break on larger areas, perhaps 20%.

That's 2,349 hours per acre, or 23.49 a bushel. At current rates, the workers would earn 50 cents a day after cost of seed and fertilizer were deducted.

In 2004-2005 the total US corn crop was 11,613,000,000 bushels. That's over 272 billion man-hours of effort if done by hand.

285 million people working 40 hours a week is only 11.4 billion man-hours, and you can't really work corn that evenly. You need two thirds of those hours divided between two 2-week periods at the beginning and the end.

I suppose you could say that wages have never really gone up. A man still makes 50 cents a day, and then gets another $99.50 a day in profit sharing on the slave (oil) wages.

Today it takes about 4 hours to make a coffee table with modern power equipment. If you had to go chop down a tree, saw it by hand into boards, and craft that table by hand, it would take a couple of weeks to do it.. but you'd still only get $100 or so for it.

But looking back at the corn -- even if all of our population worked at it, and nobody did anything else, our ability to produce food would be reduced to 4% of its current production levels.

"Food" for thought.

Archimedes said if he had a long enough lever and a place to stand, he'd move the world. If that lever breaks, what happens to the world?

[Jack]

Fascinating calculations! Thanks for taking the time to do this cogent analysis.

[Dreamtwister]

That's an interesting way of looking at it. I've considered the whole "how long would it take you to push a car for 10 miles" thing, but this is the first time I've ever considered that harnessed power in these terms.

[katkinkate]

Hi alecifel, I don't mean to criticise your mathmatic efforts, but I would like to put forward a view that all that energy usage isn't really necessary for survival or even a 'good' life. Much of the energy used can be accounted as wasted on unneeded light, excessive heat, dumped unused food. Not to mention the tendancy for people to drive places they could walk to, or to make multiple trips when one planned trip would suffice.

In the corn example, a change in agricultural method would inprove on the post oil expected yield. Using mulches and ground cover crops would reduce/eliminate the need to do the weeding and the plowing. Growing legumes as part or all of the affore-mentioned ground cover and the breakdown of the mulch and crop rotation will reduce the need for fertilizer, eventually to nil as the soil improves over successive seasons.

Modern methods tend to be very wasteful because they have all been developed with an assumption of eternal cheap energy. Why design for conservative use of energy when it (energy) is so cheap. The main thrust of design has been to make things easier for machinery in order to reduce the most expensive input in business/manufacturing/agriculture - wages.

Post peak oil society won't just crash to a level dictated by the removal of today's use of oil energy, but will trigger return to older methods and invention of new methods of doing things, that don't need the input of oil energy.

Of course I agree that it would be difficult - impossible to maintain populations at today's levels and economic standard of living without oil.

[coyote]

$this->bbcode_second_pass_quote('alecifel', 'M')an-hours per barrel = 16,800 (400 x 42)

[aflatoxin]

$this->bbcode_second_pass_quote('coyote', '')$this->bbcode_second_pass_quote('alecifel', 'M')an-hours per barrel = 16,800 (400 x 42)

[SoothSayer]

So how many teaspoons of oil would I need to say have just a few slaves going for say 20 years?

Perhaps I could find this amount by rummaging around in scrapped cars, rubbish tips etc?

[Cobra_Strike]

To the OP: A question, from part of your calculation one gallon of oil holds 400 man hours of work. Can you cite your sources for this? I know I have heard it before, but supporting information can only help your argument.