There is a close relationship between Peak Oil and population. Since the 1950s there have been many estimates of the rise and fall of global oil production, but it was perhaps inevitable that the shift has been from optimistic to realistic. After all, it is better for one’s reputation to make errors on the side of caution than to look like foolish by announcing a catastrophe that does not occur. With increasing studies, however, and with increasing proximity to the critical events, realism at last takes over.
We begin with two basic facts. The first is that the world’s present annual consumption of oil is nearly 30 billion barrels. The second is that the world’s present population is nearly 7 billion. From there we can add some reasonable estimates of both oil decline and population decline.
The peak of world oil production is about 2010, and the most likely rate of decline after the peak is 6 percent. [5, 7, 11] That means production will fall to half of the peak level in 11 years, i.e. in 2021.
Population size is directly correlated with oil supply. Oil has been the main source of energy within industrial society. It is only with abundant oil that a large global population has been possible, and it was oil that allowed population to grow so quickly. 
If oil production drops to half of its peak amount in 11 years, therefore, world population must also drop by half, i.e. to 3.5 billion. A drop from 7 billion to 3.5 means that, as with oil production, the annual population decline rate will be 6%.
But how will it be possible to reduce the population from 7 billion to 3.5 billion in 11 years? Would such a reduction be possible with a program of voluntary cessation of all childbirth, but with no other drastic global change in human behavior? Would a no-child policy be workable?
Unfortunately, such a program would be quite unlikely to succeed. In the first place, in order to have any significant effect the program would have to be both global and immediate. In addition, most of the world is hardly amenable to the suggestion of a one-child policy, such as that of China, so it is not likely that it would tolerate a no-child policy.
In any case, cutting the birth rate without increasing the death rate would not have a great enough effect on the final numbers. Since most of the people now living would still be alive in 2021, the population would not be reduced sufficiently. There is, in fact, no feasible political means of reducing population by 6 percent annually.
The only solution will be famine, and that solution will not be one that is chosen by humans. It will be chosen by Nature, as she does for so many other species. The process will be set in place by the ubiquitous and systemic decline in resources, and the consequent decline in industrial production. Without fossil fuels, agricultural yields will decline to about 30 percent. [7, 8, 9]
The famine has already started, to judge from the decline in world food supplies. [3, 4] Roughly similar declines will occur in everything from mining, electricity, and manufacturing, to transportation and communication. [2, 6]
Planning for such a scenario should have been started long ago. Even at this late date, however, what is needed is to accept the facts and to ease the way for those relatively few who will constitute the future of humanity. At least on a small scale, such a program will succeed.
1. Catton, William R., Jr. Overshoot: The Ecological Basis of Revolutionary Change. Champaign, Illinois: University of Illinois Press, 1982.
2. Duncan, Richard C. The Olduvai Theory: Energy, Population, and Industrial Civilization. The Social Contract, Winter 2005-2006. http://www.thesocialcontract.com/pdf/sixteen-two/xvi-2-93.pdf
3. Earth Policy Institute. Earth Policy Indicators. 15 June 2006. Grain Harvest: http://www.earth-policy.org/index.php?/indicators/C54/
4. -----. Earth Policy Indicators. 22 June 2005. Fish Harvest. http://www.earth-policy.org/index.php?/indicators/C55/
5. Foucher, Sam. Analysis of Decline Rates. The Oil Drum. 25 February 2009. http://iseof.org/pdf/theoildrum_4820.pdf
6. Gever, John, et al. Beyond Oil: The Threat to Food and Fuel in the Coming Decades. 3rd ed. Boulder, Colorado: University Press of Colorado, 1991.
7. Höök, Mikael, Robert Hirsch, and Kjell Aleklett. Giant Oil Field Decline Rates and Their Influence on World Oil Production. Energy Policy. June 2009. http://www.tsl.uu.se/uhdsg/Publications/GOF_decline_Article.pdf
8. Pimentel, David. Energy Flows in Agricultural and Natural Ecosystems. CIHEAM (International Centre for Advanced Mediterranean Agronomic Studies). 1984. ressources.ciheam.org/om/pdf/s07/c10841.pdf
9. -----, and Carl W. Hall, eds. Food and Energy Resources. Orlando, Florida: Academic Press, 1984.
10. -----, and Marcia H. Pimentel. Food, Energy, and Society. 3rd ed. Boca Raton, Florida: CRC Press, 2007.
11. Poston, Steven W. Decline Curves. Hamilton Group. http://www.hamiltongroup.org/documents/Decline%20Curves%20-%20Dr%20Stephen%20Poston.pdf
• Peter Goodchild is the author of Survival Skills of the North American Indians, published by Chicago Review Press. His email address is email@example.com.