Jim gave me a book called Overshoot the last time he was in town wandering around the hills. What follows are my notes taken while reading the book.

The thesis of Overshoot seems to be:

• We should think of the human population the same way that we think of any other population of creatures in an ecological system
• We've extended past the steady-state carrying capacity of the earth, and there will be a correction in population as a result

Table of Contents

1. The Unfathomed Predicament of Mankind
   1. Our Need for a New Perspective
2. Eventually Had Already Come Yesterday
   2. The Tragic Story of Human Success
   3. Dependence on Phantom Carrying Capacity
   4. Watershed Year: Modes of Adaption
3. Siege and the Avoidance of Truth
   5. The End of Exuberance
4. Toward Ecological Understanding
   6. The Processes That Matter
   7. Succession and Restoration
   8. Ecological Causes of Unwelcome Change
   9. Nature and the Nature of Man
   10. Industrialization: Prelude to Collapse
5. Resistance and Change
   11. Faith versus Fact
   12. Life under Pressure
6. Living with the New Reality
   13. Backing into the Future
   14. Turning Around
   15. Facing the Future Wisely

1. Our Need for a New Perspective

The chapter proposes thinking about human population in terms of "Carrying Capacity", a term which it leaves only vaguely defined. The idea of there being a maximum sustainable population on the Earth given a particular level of technological advancement is easy to swallow -- It's trivial to see that with present-day technology, the Earth could not sustain more than 5 x 10¹⁴ people (about 1 person per square meter of both land and sea), and equally trivial to see that the Earth could sustain less than 1000 people. So there must be a cut-off line somewhere between those numbers.

This introductory chapter then goes on to explain that the carrying capacity of the Earth with present technology is actually below the population living on the Earth, if you were to somehow remove from the picture all of the technologies which require petroleum. Petroleum, being a finite resource, will at some point run out or dwindle in availability, at which point groups of people will start villifying other groups of people for the inevitable results of overpopulation (like food shortages, price increases, whatever). The new perspective we need, the author argues, is that these pressures, when they happen, were fundamentally caused by overshooting our sustainable steady-state carrying capacity, and thus, we shouldn't be blaming (or killing) each other when it happens.

2. The Tragic Story of Human Success

This chapter lists a series of technological advances in human history (agriculture, tools, ships and firearms which allowed the Europeans to find and dominate over America) and shows a corellation between the advances and human population growth. It also implies a hand-wavy claim that until each advance, human population was living at the environment's carrying capacity. That weak non-explicit claim is the basis for an argument that goes something like this:

1. We were at or near the carrying capacity before we discovered petroleum and started building machines and using industrial fertilizers
2. That industrialization has enabled population to grow dramatically and quickly (this is a well known fact)
3. Therefore, if you were to take away petroleum, we would be above our carrying capacity

Given the amazing growth of the human population in in the past few hundred years, I'm inclined to agree with the conclusion that there are more people alive than a world without petroleum could support, even if we weren't at capacity before its discovery. But the thing the author ignores (without any compelling argument) is discoveries in the past few hundred years which, though they may now be reliant on petroleum (tractors, the electricity grid), could be adapted to use other sources of energy (electric tractors, nuclear, wind power). Yes, perhaps we're coming to a local peak in carrying capacity (any exponential growth does have to come to an end), but even without petroleum, we could support more humans with technology today than we could in 1800. When oil supplies become scarce and "tractor fuel becoms prohibitively expensive", we won't go back to using draft animals, as the book suggests -- we'll start using less powerful electric tractors.

The chapter makes one other point which (because I agree with it) I feel is worth mentioning: In general, an increase in carrying capacity can either be used by people to live more lavishly, or to support more people. If you agree with that point, that implies that an eventual decrease in carrying capacity will cause people to live more simply, or people to die. Personally, I think that if "carrying capacity decrease" caused people to stop driving 10 minutes to work every day and use a more efficient form of transportation, that would be a great thing. And as far as people dying, my guess is that unfortunately, it will happen in places that are already poor (and already have lots of people dying). If people in some region die on average at age 31 instead of age 32, will anyone even notice?

3. Dependence on Phantom Carrying Capacity

In a long term steady state, we can't rely on carrying capacity based on a resource that we use more quickly than it's replenished. The two examples given in the chapter are fishing and fossil fuels. It points out that, as humans start competing for limited resources, we tend to use them even more quickly. As fishing became more necessary to feed people, countries started to extend their territorial claims over the oceans. As oil becomes more difficult to find, the book predicts that similar things will happen. (History will tell if they already have).

The one thing I disagree with is the suggestion that we have to use fossil fuels at the exact same pace that they're replenished. That's asking humankind for too much. The important thing will be that price signals (and hopefully that will be enough) adjust people's behavior over a long enough period (say a generation or 20 years?) that any reduction in our world's overpopulation will happen mainly through normal attrition, and not through cataclysmic famine.

4. Watershed Year: Modes of Adaption

Food and energy price increases and shortages in 1973 (preceding October 6) were widely incorrectly interpreted as "arab oil blackmail," when the underlying cause was the fundamental supply of and increasing demand for petroleum. The point is made that the United States is living over the carrying capacity of its own land, and by importing oil from the Arab world is actually importing temporary carrying capacity. Shortages then trigger competition, with the U.S. suspending critical soy exports to Japan, Canada imposing drastic tariffs on oil exports, and motorists attaching each other in gas station queues. The chapter ends with a table of possible reactions to the situation. I think I fall into what he strangely calls "cynicism" (disregarding the circumstance and consequences), because I was born after the time that he's talking about. I never experienced the so-called "age of exuberance" other than in books and Bloom County comic strips. It's seemed self-evident to me since elementary school that the world is overpopulated. Although I do believe alternative electricity sources will come online as petroleum becomes to expensive (nuclear, not ethanol), I'm starting to believe that we would be lucky if we can ever find a source of energy that has as high an energy return on energy investment that petroleum has historically given.

5. The End of Exuberance

The American Dream originated from excess the carrying capacity of North America given European technology. By displacing, killing, and destroying flora, fauna, and native Americans for their carrying capacity, the settlers weren't forced to compete with each other for resources initially. Low population pressure increases the value of human life, increases wages, and removes class distinctions.

The United Nations charter sets out to improve the standard living of all people. But if there is no excess carrying capacity on the earth, that task is impossible. And the suggestion is that newly created desire in poorer countries to also live past their country's ecological means caused competition, and thus war and genocide.

Although the book hasn't (so far) phrased it in this way, the picture it paints is of a zero sum game involving living creatures (using technology) to compete for resources, with all the ramifications that situation entails. And since humans have already outcompeted most other creatures, we only have each other to compete against now.

6. The Processes That Matter

The chapter gives a elementary school ecology/biology lesson, and draws an analogy between human population and the population of bacteria in wine. The products of a species existance can sometimes kill it. It gives more examples of population pressure causing communities to villify others.

7. Succession and Restoration

A Dr. Goodwin went on a costly quest to restore Williamsburg, PA. Restoring a garden is interpreted as an example of fighting against succession. A similar fight is involved in turning the climax, or steady state community of wilderness into the contrived ecosystem that is crop fields. I find myself disagreeing with this analysis -- fields are a state of equilibrium if you include humans in your analysis. The chapter reiterates that occupants of a site may make it unsuitable for themselves over time.

8. Ecological Causes of Unwelcome Change

Thomas Robert Malthus and Darwin make the claims that populations grow more quickly than the rate needed for replacement of individuals that die, and thus will eventually exceed their carring capacities. This implies that there will be competition for any limited resources (food, water, oil are given as examples). Some interpretations of history are made in terms of that observation.

• The "American dream" was simply an outgrowth of having a low population with respect to the carrying capacity of North America (with European technology)
• Territorialism (the Spanish American War being an example) is a way for countries to capture more "ghost acreage" -- carrying capacity from overseas. U.S. territories generally failed in increasing carring capacity of the U.S.
• Immigration legislation (U.S., U.K., Australia, New Zealand are given as examples) is a result of intra-species competition

Two levels of ghost acreage are identified -- that imported via trade and that "created" using fossil fuels. The burning of fossil fuels is described as trading fossil fuels for monetary wealth. It's finally pointed out that carrying capacity can be temporarily overshot.

9. Nature and the Nature of Man

Humans have detachable organs (bike helmet mirrors are eyes in the back of the head, stone shards are better teeth or fingernails, gourds are better than cupped hands, eyeglasses, tooth fillings, artificial kidneys, hearts, prosthetic limbs, clothing, air conditioning and heat are all listed). These augments have survival value, which allows a kind of intra-species speciation, allowing humans to fill niches that they couldn't unaided. The chapter ends by reiterating the idea that a person with a higher standard of living (by using more of these "detachable organs" to become a man-tool system instead of just a man) uses up more carrying capacity than a naked human.

10. Industrialization: Prelude to Collapse

Trade is a way to overcome a local deficiency of a particular resource. The carrying capacity of two regions connected by trade is thus larger than the carrying capacity of the two taken individually without trade. The Depression is interpreted as a failure in trade. Banks failed, money wasn't available, and thus different sets of people within the U.S. couldn't trade with each other.

The book seems to want to manage chaotic forces. The author almost hints at a surprising claim: had we properly interpreted the forces that caused the great depression (and a FDIC been created early enough), it could have been avoided altogether. I'm not sure I agree that such a thing would have been possible without the benefit of hindsight. I also think that it's not a clearcut distinction between renewable and non-renewable resources as the book claims. Everything is on a continuum. Even the sun will run out of gas one day. The chapter likens human use of fossil fuels to the population of algae in a pond blooming in the spring on the detritus from the previous autumn. It asks what will happen when we need to go back to using horses to plow fields rather than using petroleum-based tractors. The book was written in 1982, I wonder if the idea of an electric tractor seemed too far out back then.

The chapter ends with what I think is a great insight: poor countries will remain poor because the earth doesn't have enough resources to support more rises like the U.S. and Europe have seen. China might end up being the last exception to that claim, and may well end up using up a good chunk of remaining fossil fuels in the process. It also gives a definition for fate that I like -- fate is the result of a preponderance of small decisions made by individuals -- trading in that horse for a tractor, or buying a car or whatnot.

11. Faith versus Fact

Fundamentalism is interpreted as a result of antagonism due to population pressure. Cargoism is described as an uninformed belief that future technology will bail us out of our problems.

• High yield crops just run through chemical fertilizers more quickly
• Switching to solar on a large scale may be risky, due to the amount of energy we'd taking out of the physical system of the earth. Solar is already being used extensively (e.g. as a pump for evaporation). Tapping solar directly to the extent needed to replace petroleum use would be comprable to the solar energy used by all living things.

I find myself agreeing that there would be risk to sucking that much solar energy out of the system. One other current use that the book doesn't mention is oxygen production by algae in the oceans.

12. Life under Pressure

Contrasts population pressure versus population density. Re-emphasizes the point that a person living a higher standard of living uses up more of the earth's carrying capacity for humans. The chapter is rather handwavy. Gives as examples: energy use per person, pollution from factories, and more autos per capita as examples of humans with higher standard of living being more likely to start treading on other people's lives one way or another.

13. Backing into the Future

Population cycles have happened to humans before (Easter Island, 1680). Food production and distribution there was too sensitive to social disruption, and population pressure caused a genocidal war. Perhaps by being more aware, we can avoid killing each other on a global scale. Reindeer on St. Matthew Island also went through a dramatic population cycle.

We sense overpopulation locally as increased competition. We tend to lash out in response -- find a group to blame for our fear of being redundant.

14. Turning Around

Carter's energy proposal was insightful but incomplete -- there's unfortunately no basis for believing we can still increase people's standard of living overall.

Coal is perhaps better used as storage of carbon than as fuel

Climate change might hurt agricultural output, which would be another way carrying capacity decreases

The author suggests people adopting a lower standard of living. To me, this seems flawed just like all the other solutions shot down in the book -- people will live more cheaply, which will only raise the carrying capacity again temporarily. Lowering everyone's standard of living just postpones the problem. The only real solution, in my mind, is for people to die (hopefully of old age).

The author suggests that advertising is to fault for creating a culture of want (which causes people to try to increase their standard of living). Again, while I agree that advertising does that, I think it's flawed to point to that as a solution, as really the only real solution to overpopulation is to have less people

15. Facing the Future Wisely

Yes, technology will help increase carrying capacity, but is it rational to believe that it will continue to do so indefnitely?

Also, technology that uses non-renewables will eventually cause carrying capacity decline when the resources run low

Population crashes in Ireland in 1727, 1739, and 1845, due to reliance on potatoes. The 1845 crash was due to a fungus which in effect started competing with humans to consume potatoes.

Lynx & snowshoe rabbits have well known population cycles

The author then launches into a rather befuddled prediction of whwat will happen, where the author claims to believe that human population (in 1982 when the book was written(?)) exceeds both the steady state and the energy augmented carrying capacity of the earth. Doesn't this violate the definition of carrying capacity?

The author seems to be coming from the point of view of trying at all costs to avoid people dying. If the problem is overpopulation, I don't see how that's possible.

More population cycles are described. The observation is made that as the ecosystem becomes simpler, with fewer species competing for consumption, the population cycles become more dramatic.

As we take over more land for farms and get rid of more complex ecosystems, we actually move the earth toward that simple one-consumer state, and move ourselves closer toward a place where our population will go through those dramatic cycles too.

The book concludes with a great point, which is that if we assume that overpopulation is not a problem, we will make decisions that will cause it to become a much bigger problem when it does hit. By assuming that it already is a problem, we can start doing actions to slow down our population growth and hopefully make the population correction less wrenching.

Conclusion

Although I found parts of the book repetitive, it has changed my perspective. I agree with most, but not all of the arguments put forward, and I think that for at least a while, I'll probably interpret all sorts of human conflict as people or populations bumping into each other ultimately because of population pressure.