The creation of the Hubbert curve was filled with contradictions – its current utilization to predict peak resources fails on all levels – assumes lack of innovation

In the 1956 presentation of his model, Hubbert preceded his theoretical prediction of peak oil production in the United States with a discussion and plotting of some select cases of the history of mineral production. These cases included the world production of coal and crude oil (Hubbert, 1956, p. 9), United States production of coal and crude oil (Hubbert, 1956, p. 10), and Texas production of crude oil and natural gas (Hubbert, 1956, p. 10). All of these curves showed exponential growth without decline. To extrapolate the curves, Hubbert invoked two axioms. First, production must begin and end at zero. Second, the total area under the production curve had to equal the size of the ultimate resource, a static number in Hubbert’s mind. Because Hubbert was well aware that theoretical models needed empirical corroboration, he invoked the case history of petroleum production in the state of Ohio. Hubbert noted that production began a “sharp rise in 1884, passed through three maxima between 1890 and 1900 with the peak about 1896, and since then has undergone a slow, steady decline” (Hubbert, 1956, p. 12). A second case considered by Hubbert was oil production in the state of Illinois. The production curve for Illinois did not resemble the curve for Ohio. In the case of Illinois, there were two separate peaks, with the second peak being approximately four times higher than the first peak. Any prediction of resource exhaustion inferred from the first part of the curve would have been grossly in error. Hubbert noted that the existence of the two peaks was due to the introduction of new technology: “A new cycle of exploration using the seismograph was initiated in 1937” (Hubbert, 1956, p. 12). Apparently dismissing or ignoring the implications of the case of Illinois for making valid predictions of future production, Hubbert proceeded to make predictions for peak oil production for both the United States and the world from a single bell-shaped curve. A common misconception is that Hubbert’s curves were Gaussian. This is not correct. The curves in the 1956 predictions were drawn by hand. Later, Hubbert (1982) formally based production curves on the logistic equation originally derived by the Belgian demographer Pierre François Verhulst (Deming, 2001). Hubbert (1956) estimated that the size of the ultimate recoverable resource in the United States was 150 billion bbl. Being fully aware that past estimates had been too low, sometimes grossly so, Hubbert also calculated a curve for the higher number of 200 billion bbl. He characterized the extra 50 billion bbl as “an amount equal to 8 East Texas oil fields,” the implication being that he considered this to be an absolute, if not exaggerated, outer limit of what was possible (Hubbert, 1956, p. 18). The two curves yielded peaks in the years 1965 and 1970, respectively. Hubbert conceded that secondary recovery techniques could increase his estimates of the resource size, but he only anticipated that the “effect of improved recovery will be to reduce the rate of decline after the culmination” (Hubbert, 1956, p. 18). The timing of peak production would remain unchanged. Hubbert pressed ahead with this analysis even though the admission of its very unsoundness was explicit. He assumed, without justification, that oil production in the United States would mimic the case history of Ohio, not that of Illinois. Ironically, the production curve for crude oil in Ohio, which appeared to follow Hubbert’s peak oil model for several decades, later diverged and exhibited multiple peaks. In 2019, the oil production of Ohio exceeded 27 million bbl, surpassing peak production in the 1890s (US Energy Information Administration, 2023). Hubbert continued to revisit the peak oil hypothesis for the rest of his career. In 1967, he noted that there had been a “succession of recent assurances that the oil present in the United States may be as much as 3-5 times that discovered already” (Hubbert, 1967, p. 2208), but stuck with his earlier appraisal that the size of the ultimate recoverable petroleum resource in the United States would not exceed 200 billion bbl. Hubbert again explicitly conceded that “the curve reaches one or more maxima” (Hubbert, 1967, p. 2209), but then stuck with his original 1956 prediction of peak oil production between 1965 and 1970, based upon a single symmetric curve.