The Hubbert Curve

When the historians of some future civilization write about the times we are living in now it is possible that two phrases will be frequently quoted. They are ‘Hubbert Curve’ and ‘Limits to Growth’. They will use these terms to illustrate how the people of our time were well informed as to the predicaments that were heading their way, but they chose not to take action.

In this article we provide some background to the first of these: the Hubbert Curve and its relevance to climate change. (In one science fiction story set at a time about three hundred years from now his name is treated as a cuss word; where we would say “by God!” the people in the story say, “By Hubbert!”).

In the year 1979 Alfred North Whitehead said,​

The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.

A similar comment can be made about Hubbert — so much of our current discussions to do with resource constraints has its roots in what he wrote over sixty years ago. Most current Peak Oil writings are essentially footnotes to Hubbert's work. He said,

The fossil fuels . . .  have all had their origin from plants and animals . . . during the last 500 million years. Therefore, as an essential part of our analysis, we can assume with complete assurance that the industrial exploitation of the fossil fuels will consist in the progressive exhaustion of an initially fixed supply to which there will be no significant additions during the period of our interest.

He understood that there is a finite amount of oil in the ground, and that when it is gone it is gone. It will only be replaced over the course of many millions of years. He then went on to provide a mathematical form — the ‘Hubbert Curve’ — that described this predicament.

M. King Hubbert

M. King Hubbert

Marion King Hubbert (1903-1989) was a geologist and physicist who worked for the Shell Oil Company in Houston, Texas, and then for the United States Geological Survey. Hubbert's early insights into the fundamental problems to do with oil depletion provide the foundation of much of today’s thinking regarding the limits not just of crude oil but of any natural resource.

​Hubbert wrote a series of papers to do with with oil reserves and the rate at which they decline. He did not use the term ‘Peak Oil’, but he developed the concept. His basic idea — which seems obvious to us sixty years later but which was far from obvious in his time — was that all oil reserves have a finite life and will eventually be depleted. Geologists in his day knew this about individual oil wells, but he scaled up the discussion to consider reserves in much larger regions, such as the States of Texas and Illinois. His insights resulted in the now famous Hubbert Curve.

As a leading scientist employed by one of the world’s largest oil companies Dr. Hubbert  was authoritative and credible. The four pages of citations in his seminal paper confirm his commitment to thorough and professional research. He was also willing to say what his thought, in spite of the fact that his employer tried to prevent him presenting that paper.

The 1956 Paper

Hubbert presented his paper Nuclear Energy and the Fossil Fuels at an American Petroleum Institute (API) meeting in San Antonio, Texas in March 1956. In it he showed what is now referred to as the ‘Hubbert Curve’. It is Figure 29 in the following image. (Note that the paper was typewritten — he was working long before the use of even the simplest word processors.)

Hubbert Curve
The Hubbert Curve

The reasons for the paper being so foundational include the following:​

  • He discussed the issue of fossil fuel production in a global context.
  • He recognized the finite nature of fossil fuel reserves.
  • He developed a generic (Hubbert) curve to show how production of fossil fuels peaks and then declines.
  • He understood the fact that continued exponential growth in a finite world cannot continue.
  • He had a grasp of the social implications of his research.

​The Age of Happy Motoring

Hubbert was not only creative, he was also courageous. What he said was very much counter to the ‘Happy Motoring’ culture of his times. In 1956, the year that he presented his paper, oil production in the United States was increasing, the giant fields in the Middle East were coming on stream, and the new energy source — nuclear power — was going to be too cheap to meter.

The paper also showed how he anticipated that nuclear power would smoothly take care of the decline in petroleum production. Nuclear power is the dashed line in the Hubbert Curve drawing. This prediction did not, of course, turn out to be accurate. 

Hubbert curve including nuclear

Moreover, in the years since his passing new discoveries of oil in locations such as Alaska and the Gulf of Mexico have maintained production. (Shale oil has also added to the supply, but it is likely that this effect will be short-lived given that very few of the shale plays are profitable.) 

Nevertheless, the fundamental insight remains correct. Once a new field is discovered, its production rises and then falls as shown in the Hubbert Curve.

Other Resources

Although Hubbert  applied his research to just the oil reserves in the United States the principles he used can be applied to any non-renewable resource or to a resource that is depleted more quickly than it can be replaced. For example Hubbert curves have been developed for coal and for fish stocks in the ocean.

Analysis of the 1956 Paper

Because of its importance and because many of the issues that he raised are with us still it is worth reading Hubbert’s 1956 paper in detail and analyzing his findings and conclusions.

​His paper is in three parts. The first part analyzes the fossil fuel industry of his time (the early 1950s) and provides forecasts as to likely production rates over the next half century. The second part of the paper is to do with the transition that he expected to see from fossil fuels to electricity generated by nuclear power plants. The third part of the paper, an assumption that society will respond to analyses such as his rationally, is implicit in the overall context of his analysis.

Part 1 — Fossil Fuel Reserves

In the first part  of the paper Hubbert analyzed the oil industry in the United States in the early 1950s. He also made forecasts to do with future production that turned out to be accurate. Later, he predicted the timing of peak oil production world-wide. His forecasts as to the amount of oil that would be discovered and produced were low as regards quantity, but the timing was spot-on. (He himself recognized that new sources of oil would be discovered. For example, more than a decade after the publication of his paper the fields in the North Sea and Alaska’s Prudhoe Bay became a major factor in the world’s oil production picture.)

​The following quotation summarizes his understanding as to how oil production would change in the coming decades.​

. . . world production of crude oil increased at a rate of 7 per cent per year, with the output doubling every 10 years.. . . How many periods of doubling can be sustained before the production rate would reach astronomical magnitudes? No finite resource can sustain for longer than a brief period such a rate of growth of production; therefore, although production rates tend initially to increase exponentially, physical limits prevent their continuing to do so. This rapid rate of growth for the production curves make them particularly deceptive with regard to the future length of time for which such production may be sustained. 

​In other words, fossil fuels are a finite resource; they cannot be replaced except over many millions of years.

Hubbert drew a clear distinction between the three kinds of fossil fuel (solid, liquid and gaseous) but did not anticipate any issues to do with moving from one to another.

Part 2 — Nuclear Power

The title of his paper – Nuclear Energy and the Fossil Fuels – illustrates Hubbert’s fundamental optimism. He anticipated that society would make a smooth transition from fossil fuels to nuclear power and that economic growth could continue.​

This prediction missed the mark. Although the nuclear power industry now constitutes an important part of the overall energy mix, the optimism that Hubbert showed regarding the transition from fossil to nuclear fuels has not occurred in the manner that he anticipated. ​It turns out that different energy sources are not nearly as fungible as was thought in the 1950s. The world now has close to a billion vehicles (automobiles, trains, airplanes, trucks, ships) that run on fossil fuel. Although we see some attempts to introduce electric cars, the reality is that electricity from nuclear power plants is not a direct replacement for gasoline and other refined products, at least not on a realistic time scale. ​

The civilian nuclear power industry was just getting started in 1956 with promises of energy that “would be too cheap to meter”. In hindsight it is now evident that Hubbert was much too optimistic. Although the nuclear power industry meets a large fraction of the world’s demand for electricity, it has not been the savior that Hubbert anticipated. Costs have been far higher than anticipated, accidents such as Chernobyl and Fukushima-Daiichi have shaken public confidence to do with the safety of the industry, and issues to do with the disposal of radioactive waste remain unresolved.

​Part 3 — Society’s Response

Throughout Hubert's paper lies an unspoken assumption that, when presented with the facts and analyses shown in papers such as his, then we, as a society, will take the appropriate actions. In 1956 there was sufficient time to make the transition from an oil-based society to one that derives most of its energy from nuclear power. We have since learned to be more skeptical — people generally do not plan for the medium or long-term future. They look mostly to satisfy their own immediate needs and wishes.

​We now see that Hubbert was rather too hopeful, maybe a little naïve. It seems as if he thought that, by merely identifying the problem, society would respond appropriately. That did not happen. No serious attempt was made in his day to address resource constraints, and little has changed since then.

Relevance to Climate Change

There are two issues that Hubbert raises that will affect climate change. The first is that the models that project continuous growth in fossil fuel use my be misleading. If we do reach a point of peak oil then we will be adding less CO2 and other greenhouse gases to the atmosphere. 

The second concern is more worrisome. If all types of resource are finite in nature, and subject to their own Hubbert Curve then we may find that we do not have enough of the necessary materials to transfer our entire energy production to alternative sources.

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