Hubbert's Peak: The Impending World Oil Shortage
by Kenneth S. Deffeyes
208 pp. Princeton University Press - 2002.
Reviewed in American Journal of Physics by Mark P. Silverman
I have read numerous books that were informative, a smaller number that in addition were entertaining, and very few that had the potential, as well, to be life-changing. Hubbert's Peak is in this last category. That we live on a finite planet with a finite fossil energy supply may seem upon reflection an obvious, if not banal, observation. However, to judge from the relatively low level of public concern over the rate at which nonrenewable resources are being exhausted, it is fairly clear that most people do not think about, or do not understand, the sweeping implications of this simple fact. M. King Hubbert first brought the "bad news" to the oil industry in 1956. And Kenneth Deffeyes, through the medium of this comparatively short, highly readable, and carefully argued book, is bringing it to the general public.
A geophysicist by training, Marion King Hubbert made numerous scientific contributions of a fundamental nature. For example, he demonstrated that fluids can become trapped under circumstances previously not thought possible, and that even the hardest rocks on the earth's surface become soft like mud or clay when subjected to enormous pressure. However, what projected Hubbert to fame - or notoriety - was his assessment of the finite availability of the world's petroleum supply. In 1956 at a meeting of the American Petroleum Institute, Hubbert - against the strenuous objection of his employer, the Shell Oil Company - predicted that U.S. oil production would reach a peak in the early 1970s. This is bad news indeed if one is counting on an endless supply of accessible and cheap petroleum to sustain an unrealistic vision of unremitting economic growth. Although there have been numerous cries of wolf in the past, Hubbert's prediction was close to the mark: the peak year for U.S. oil production turned out to be 1970. Since this time, the United States has been an oil importer.
"The present state of human affairs," Hubbert wrote in a 1949 Science article ("Energy from Fossil Fuels"), "can best be appreciated in the light of a time perspective, minus and plus, of some tens of thousands of years from the presentÉ The consumption of energy from fossil fuels is thus seen to be but a 'pip,' rising sharply from zero to a maximum, and almost as sharply declining, and thus representing but a moment in the total of human history." This delta function of oil exploitation against a geological time scale of hundreds of millions of years of oil accumulation constitutes Hubbert's peak. The bad news: once you've gone over Hubbert's peak, there is no climbing back up.
But why should we believe Hubbert? After all, as Deffeyes, who was himself a close colleague of Hubbert during the time he too worked for Shell, writes: "We scientists don't like to admit it, but we often guess at the answer and then gather up some numbers to support the guess. ... Hubbert's oil prediction was just barely within the envelope of acceptable scientific methods. It was as much an inspired guess as it was hard-core science." Certainly the oil companies must have thought so for, according to Deffeyes, "...neither Shell nor the rest of the oil industry was ready to listen to Hubbert's prediction. It was as if a physician had diagnosed virulent, metastasized cancer; denial was one of the responses." Indeed, even as recently as 2000, Deffeyes informs us, the president of the American Association of Petroleum Geologists published yet another denial of the validity of Hubbert's results.
Looked at superficially, there is a certain deceptive simplicity to Hubbert's model that has invited numerous criticisms. Fitting the annual rate of oil production then available to him with a symmetric curve, Hubbert deduced the projected peak year of production and, from the area under the curve, the total consumable supply. There are many ways, however, to thwart Hubbert's argument, and the author, who has a whimsical sense of humor, proposed the following as his favorite: "...[I]nvite the Saudis to join us as our 51st state." - this was undoubtedly written before 9/11 - "Now you count the Saudi oil as U.S. oil; Hubbert is toast." Deffeyes, of course, clearly recognizes the fallacy of such reasoning, since "...first you must draw a line around the problem and then discuss what goes on inside the line. Fudging the line, either geographically or categorically, only makes a mess out of the discussion." True, but there is more to this fallacy than fudging boundary lines. Hubbert's model embodies truths much deeper than curve fitting.
I have been teaching energy and society courses for many years, usually to students whose facility with mathematics is rather limited, and have unfailingly evoked a certain degree of consternation whenever I worked out on the blackboard the simple consequences of geometric growth - as, for example, the time required to exhaust a nonrenewable resource whose annual consumption increases at a fixed rate. I usually worked with geometric, rather than exponential, growth because the former involves no more than algebra, whereas the latter entails the calculus, but the results were close either way and invariably surprised those (the majority of the class) who were not exposed before to the idea of compounding. Thus, a resource like coal or petroleum, which might have lasted for over a thousand years if annual consumption remained constant, is found to last considerably less than a century when the annual production increases at even a relatively low fixed rate. But more disturbing is the realization, ineluctably following the logarithmic dependence of duration on supply, that the discovery of an oil field or coal vein many times larger than all currently known merely extends the availability of the resource by only a short span of time when measured against a human lifetime (or the time a society would need for the commercial implementation of new energy technology). So even if Saudi Arabia became the 51st state one day, without a radical reform in the consumption of fossil energy Hubbert's peak would still stand out like Everest, only shifted a bit along the timeline.
Deffeyes writes that "[d]espite sharing 100 lunches and several long discussions with Hubbert, I never had the guts to cross-examine him about the earliest roots of his prediction. Lunch discussions were more cheerful when Hubbert chose the topic." (Early in the narrative we learn that Hubbert can be rather difficult to get along with; the saying in the lab was "That Hubbert is a bastard, but at least he's our bastard.") Having read some of Hubbert's papers myself, I am puzzled by this uncertainty of the author, who after all knew Hubbert well. The roots of the prediction seemed quite clear to me, for I found Hubbert (like Deffeyes) to be an articulate, clear, at times movingly eloquent writer. I would speculate, even if Deffeyes would not, that Hubbert arrived at his method of resource analysis by the inverse of the procedure that is recounted in textbooks.
If one believes a resource is limited, then, barring artificial barriers to discovery and production posed by political upheavals, the exploitation of the resource almost certainly must take a path more or less like the following. At the outset, when the resource is first discovered and the infrastructure for exploiting it is still nascent, production is slow. With increasing maturity, the industry can recover more of the resource in less time; the cumulative production curve rises steeply. Upon nearing depletion of the recoverable supply, the cumulative production approaches its limiting value asymptotically. Thus, cumulative production takes the general form of an "S", i.e. a sort of logistic curve, and the point of steepest slope gives the time of maximum rate of production.
Vicissitudes of politics and the real-world marketplace may put numerous bumps and wiggles into the "S". Maybe the productivity curve will not be symmetric. Maybe it will not have one peak, but several peaks or a plateau. In the overall scheme of things these are minor quibbles. Numerical predictions of time and quantity may change, but none of this changes Hubbert's fundamental conclusion that an effectively nonrenewable resource ultimately will be exhausted at a rate that depends in some way on the amount that is produced and the amount that remains to be produced.
To this seemingly pessimistic conclusion a nonbeliever may be inclined to raise an array of objections. What about the natural formation of new oil? What about new technology to recover more old oil? What about drilling deeper to tap the vast supplies of oil that must lie below the depths hitherto reached? What about drilling in the various corners of the globe that have not yet been explored for oil? And so on. Alas, the reader who looks to such ultimate fixes will not find comfort in Deffeyes' lucid and masterful narration, which comprises the greater part of his book, of how oil formed, where it is to be found, and how and to what extent it can be recovered. Since the enjoyment and edification of the book lie in the details of Deffeyes' personal account, it will in no way diminish the pleasure of reading it when I state briefly the damning conclusions that: (a) Any oil, if indeed there is any, that forms over the next 10,000 years would be but a drop compared with the past available supply. (b) New technology will not recover sufficient oil to meet the growing demand. (c) Beyond a certain depth there is no oil to be recovered because the high temperature within the Earth's mantle has decomposed organic matter into methane, the simplest hydrocarbon. (d) With a couple of exceptions, there is virtually no place on Earth that has not yet been explored for oil.
Some years ago I attended a session at - of all places - a meeting of the American Physical Society and listened incredulously to an eminent physicist describe how vast quantities of oil currently exist and are being produced deep underground, and that apparently depleted oil fields will be renewed by extensive upwellings from below. There was little reason to believe that then and less reason to believe it now. Rather, it is Hubbert, whose perception of the situation is the one I would wager on, as quoted again from his 1949 paper in Science:
"The release of [fossil] energy is a unidirectional and irreversible process. It can only happen once, and the historical events associated with this release are necessarily without precedent, and are intrinsically incapable of repetition. It is clear, therefore, that our present position on the nearly vertical front slopes of these curves is a precarious one, and that the events which we are witnessing and experiencing, far from being 'normal,' are among the most abnormal and anomalous in the history of the world. Yet we cannot turn back; neither can we consolidate our gains and remain where we are. In fact, we have no choice but to proceed into a future which we may be assured will differ markedly from anything we have experienced thus far."
Time has passed and we are no longer on the "vertical front slope" of the oil curve as when Hubbert first wrote those words in 1949. We are over Hubbert's peak and we still do not have a sensible, coherent, effective national energy policy to avert the day of reckoning when no sum of dollars will be able to buy what is no longer available for purchase. Kenneth Deffeyes gives an enlightening and compelling justification of Hubbert's portentous conclusions that should make thought-provoking reading for anyone concerned about the consequences of the eventual depletion of petroleum. The author himself, convinced by Hubbert's reasoning that there was quite literally no future in oil, gave up the well-compensated carefree life of an oil company geologist for the hard labors and low pay of a Princeton University professor.
About the author
Mark P. Silverman is Jarvis Professor of Physics at Trinity College. He wrote of his investigations of light, electrons, nuclei, and atoms in his books Waves and Grains: Reflections on Light and Learning (Princeton, 1998), Probing the Atom (Princeton, 2000), and A Universe of Atoms, An Atom in the Universe (Springer, 2002). His latest book Quantum Superposition (Springer, 2008) elucidates principles underlying the strange, counterintuitive behaviour of quantum systems.