Neolithic farmers got back about ten or twenty calories for every calorie they expended in work. In those cultures, ninety percent of human power, call it the labour force, was involved in food production. Now, the human energy involved in food production is maybe ten or fifteen percent. Modern farmers using machinery, fertilizers and pesticides use about eight calories for every one produced. By the time these foodstuffs reach the table, twenty to thirty calories have been ‘burned up’ to produce every single calorie consumed. This is the result of entropy in the food chain, which can be described in different ways.
A thousand pounds of grain fed to cows produces one hundred pounds of beef, which when consumed by one human, produces one pound of corresponding flesh. It’s a ten-to-one ratio from one level to the next of the food web according to a well-known theory. One wonders if it’s ten-to-one when it’s a whale shark eating krill. But for every thousand pounds of krill ingested, there probably is a ratio of ‘productive work.’
In the example of the cow, much of the benefit of eating the grain went to wasted work—the animal walked around in a field, it mooed, it wagged its tail to keep off flies. Much of the energy burnt was consumed buy the very act of eating and digestion. It was wasted energy in the sense of entropy in the food chain. The whale shark didn’t spend all of its energy ingesting krill, it also propelled itself continuously through the water in order to obtain that krill. The whale shark is burning food energy to produce more food just as we do. Incidentally, the thousand pounds of grain would have done more ‘work’ if we simply consumed it as grain. That’s because ten people each could have consumed one hundred pounds of that grain and it would have gone into the making of one corresponding pound of flesh. This is a simplistic view, but bear with me.
If you go back to hunter-gatherer cultures, it’s estimated they spend about twenty hours a week providing food, shelter and clothing for themselves. It’s been called the original affluent society, because the people want for nothing and have plenty of free time to enjoy the most important things in life, which are friends and family.
Admittedly, they live in grass huts and go around mostly naked. In our eyes they are poor. But one of the costs of modern society in all of its energy-richness, is that we tend to take up all the slack in a thousand meaningless activities designed to burn off all of our own surplus of free time. We are also an affluent society.
At one time in the exploration and extraction of fossil fuels there was a ratio of about a hundred-to-one in terms of entropic value. Nowadays it’s more like ten-to-one. For every one calorie of energy expended, we now only get ten back in terms of caloric value, whether it’s for automotive fuels or home heating. The great thing about fossil fuels is the caloric value. It is amazing that a single gallon of gas can push that big heavy vehicle at highway speeds for thirty or forty miles. It really is a kind of miracle when you think about it, and I think that’s why so many of us simply take it for granted: because it’s kind of incomprehensible how all that energy, all that work can come out of such a small amount of some aromatic fluid. Try imagining that with a gallon of water. Theoretically, there’s all kinds of energy locked in there.
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The indications are this ratio will deteriorate further still, in fact, that’s one reason why the price of energy is both high in historic terms and volatile in terms of everyday markets. Another reason is increasing demand, due to the increasing complexity of our systems. Thirty years ago, very few people in China owned a car. Now it is becoming much more common.
The system is becoming more complex.
The more complex a system becomes, the more demanding it becomes.
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Political events, such as a revolution in the Middle East, often have an immediate impact on energy prices, with a trickle-down effect on other industries. Simply put, if the price of energy goes up today, the price of sowbellies is going up not too far down the road. Modern society has replaced human energy with chemical and nuclear energy to perform much of its work. These models are models of abundance at low efficiency. The typical auto engine has an efficiency of twenty –five to thirty percent. The most modern nuclear reactors have an efficiency estimated at forty-five percent.
Simply doubling the efficiency of what we already have would solve many of our energy needs for the immediate future. The effect of thermodynamic entropy is so strong that this seems unlikely to be achievable using known processes, both technical and theoretical. This is an entropic aspect of knowledge itself. It takes more energy to learn what we need to know than it might generate in added efficiencies. That’s why old technologies linger. It’s not that they are the best, they are simply more efficient in achieving immediate goals in terms of pure cost-benefit analysis. As you might expect, the efficiency of some of our modern institutions isn’t particularly high. They merely work and solve an immediate and ongoing need, essentially because no one has any better ideas. All new ideas involve risk, and at least old technologies involve easily-understood risk factors. In entropic terms, it’s easier to keep the old thing going rather than get the new one up and running.
The trouble with entropy in the societal sense is that we have to keep the whole shebang going, or we return to barbarism. We have no choice but to stay ahead of that entropic curve. We can conceive of no other choice. Perhaps that is a truer statement.
Social entropy means that the more we attempt to impose our artificial order, the more complex the system becomes, and thus the greater the rate of breakdown of its constituent parts—classic thermodynamics applied to fairly large and heterogeneous groups of people, much of whose energy is dissipated in seemingly random, even nonsensical activities. Many have little to do with providing for material needs. This might include religion, or tattoo parlours, or the jewelry industry, or the glamorous international world of cheese connoisseur magazines. They must have some benefit to society, however intangible. They contribute to GDP. In some weird sense, GDP, gross domestic product, is a measure of the ‘work’ output of a social system, not in caloric terms but monetary terms.
http://secondlawoflife.wordpress.com/2007/07/28/entropy-and-the-food-chain-part-i/
http://en.wikipedia.org/wiki/Social_entropy
http://en.wikipedia.org/wiki/Entropy
http://en.wikipedia.org/wiki/Generation_IV_reactor
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