(This is Part 20 of a series. Go back to Part 19.)
As we've seen, societies are open systems that maintain their order only by a continuous flow-through of energy. And we've seen that a society can obtain new energy by either taking over an existing source (conquest) or by utilizing a new form of energy (technology).
And in either case, the law of diminishing returns will eventually apply. The easiest and least costly means of acquisition will be used first; as these are used up, of necessity more difficult and more costly means must be used. Moreover, the complexity necessary to acquire and maintain these more difficult means is itself a source of increasing costs.
Thus, the increasing complexity assiciated with the new energy supply eventually returns fewer benefits than the cost of maintaining that complexity, and when a society enters upon this declining marginal curve it becomes vulnerable to collapse, as seen with the Roman Empire.
But in modern times our "society" can only be considered the entire world. And the colossal energy source that the world discovered and has built its immensely complex civilization upon is fossil fuels.
Our entire global society is now constructed on top of, and dependent upon, fossil fuels. Over 85% of all the energy used in the world comes from fossil fuels.
As Jeremy Rifkin has put it, " We heat our homes and businesses with fossil fuels, run our factories with fossil fuels, power our transportation with fossil fuels, light our cities and communicate over distances with electricity derived from fossil fuels, grow our food with the help of fossil fuels, construct our buildings with materials made from fossil fuels..."
The discovery of fossil fuels provided the human race with the greatest energy subsidy that our species had ever seen. One measure of its transformative effect was that the human carrying capacity of the planet went from one billion people in 1820 to over six times that less than two centuries later, the fastest increase in history.
The first oilwell was drilled in 1859 in Pennsylvania. And the initial returns were simply staggering. Within just a few decades monumental changes had occurred, ranging from the automobile to the electrical grid to the airplane to mass-market production and pricing, an economic and societal transformation almost beyond recognition.
To measure the benefit-to-cost ratio of energy, the energy industry uses a term called EROEI—Energy Returned On Energy Invested. It takes energy to acquire and distribute energy. EROEI is the ratio of the energy received versus the total energy expended to get it.
In the expansion phase of industrial civilization, EROEI is estimated to have been over 100-to-1, by far the highest such ratio in human history. A staggering energy source had been discovered and human society embarked upon a phase of prosperity and complexity never before seen.
This, of course, was the primary effect.
(This is the end of Part 20. Go to Part 21.)
—jim sloman, 10.16.04 for May 13
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