Sign of the Times

It was with something like an apology that Earl Cook, a geologist and executive secretary of the division of earth sciences at the National Research Council, began his December 1972 article for Technology Review on the energy issues that he felt people would face in the next millennium. Geologists tend to take the long view of our existence on this planet, but Cook worried that his readers would fail to see the relevance of his points.

It may seem only a pleasant intellectual excursion without practical significance to attempt to look either back or ahead on a scale of centuries at man’s use of energy resources. Given the exigencies of public decision-making, this venture may be just an intellectual excursion and nothing more. But bear with me … .

He needn’t have worried: the following year brought the OPEC embargo, which revealed how utterly dependent we were on access to cheap energy. But of course, the oil shortage caused by the embargo was due to political conflicts, not geology. What motivated Cook was an idea that was then somewhat novel: that we were fast approaching the limit of the fossil fuels we could extract from the earth.

Throughout most of his history as an identifiable species, man relied on renewable energy resources for food, heat, protection from other animals, and to power boats, drive mills, lift water, and pull plows. Only about 150 years ago did he start, on a significant scale, to switch over from wood and wind, from animals and falling water, to heat and power derived from the nonrenewable resources which we call the fossil fuels. In a brief span of little more than a century, industrial-technological man has become utterly dependent on nonrenewable energy resources. Moreover, he has allowed his and the whole world population to expand enormously on the basis of a rate of energy supply that cannot possibly be maintained … .

Cook was careful not to get ahead of himself, since he knew that his readers would have seen no evidence of this imminent crisis as yet. He also acknowledged that we could defer a crisis by finding ways to get more energy out of the ground or by developing technology, like cars with improved gas mileage, to make better use of it. But he insisted that none of those solutions would be permanent. “We are dependent on nonrenewable resources which have finite quantity limits,” he wrote. In other words, one way or another, we were going to run out.

The big question then and now is: how much time do we have? Cook felt fairly certain that “world crude will not be available beyond about 2025.” It turns out not to be as dire as he thought. Oil companies have pushed back the day of reckoning by drilling in remote places (the oil that poured into the Gulf of Mexico from a well nearly a mile below the surface offers testimony of the lengths, or depths, to which we’ve gone). The International Energy Agency now predicts that we won’t reach peak petroleum production until at least 2020, and that we may then see a production plateau or slow decline rather than a calamitous plunge (see Briefing).

Cook argued that even if we could buy ourselves a few more decades or even a century, a crisis was inevitable–one that would threaten the lives of billions around the world. Although people today tend to think mainly of how a declining oil supply would affect the economy, Cook was more concerned that without abundant fossil fuel or a renewable replacement for it, the global population would be unsustainable.

Population is a function of the rate of useful energy supply, whether or not that energy comes from renewable or nonrenewable resources. If it comes from renewable resources, the rate cannot rise more than briefly above the rate of renewal and therefore populations tend rather quickly to become stabilized in ecological equilibrium with the rate of supply. …

A population based on nonrenewable resources, on the other hand, faces a much more formidable instability problem. Its rate of usable energy supply depends not on man’s efficiency in extracting energy from a dynamic system constantly being renewed but upon the rate he chooses to extract energy from a static system that is not renewable on any time scale meaningful to him. The more he allows his numbers to become dependent on this self-chosen rate, the more he faces ultimate catastrophe.