Population Decline - Red Herrings and Hope

[GliderGuider]

The linked article is a cleaned-up version of a debate I had here recently. It summarizes why I think the human population is in four a rough time in the near future regardless of efforts being made to control it. I'd like to thank DUer HamdenRice for providing a good summary of the mainstream position and prompting this article.

Population Decline - Red Herrings and Hope

In recent years demographic experts have been revising their peak human population estimates downward. At one time, peak population was feared to be in the tens of billions. Then it was revised down to 12 billion. But fertility rates continued to drop, to the point where our population is now projected to peak around 9 billion sometime in the middle of this century. This decline is being driven by some well-recognized factors:

(snip)

The world has entered a demographic phase of plummeting fertility rates -- in many countries to below the magic "replacement" fertility rate of 2.1 children per woman, which implies zero population growth or even "sub-replacement" fertility rates that imply a slow decline in overall human population. Much of Europe is worrying about and developing plans to deal with slowly declining populations. So in the opinion of mainstream demographers we now have an excellent opportunity to have a "soft landing" in population rather than the population explosion and crash that so many have been fearing for decades.

Or do we? Might the rejoicing over falling fertility be, if not a red herring, at least a trifle premature? This article makes a case for extreme skepticism on this issue. Yes, population growth is slowing, and all the factors cited above are contributing to that. However, there are a number of inconvenient truths that are not addressed in this rosy analysis. They change the picture dramatically when they are included.

(snip)

As our ability to maintain a complex high-energy civilization is compromised by the loss of its master resource, Liebig's Law of the Minimum will come into play to stop its growth. Food production and distribution will be hampered or in some cases made impossible, and due to the damage of soil and water local agriculture will prove very difficult in some places. If medical care erodes, so does infant mortality and longevity. The erosion of urban sanitation systems will have an identical, and possibly greater, effect. The effects will be highly variable, with some places like the United States suffering from the catastrophic decline in net global oil exports that is now underway. Other countries like those at the bottom of the list of developing nations will simply be too poor to compete against the developed world for the resources needed for survival. Populations will fall as a result.

Based on my understanding of the oil situation and my developing understanding of man's position within the earth's ecology (especially that we are in at least a 50% overshoot situation without oil's help) I predict that the global population will never rise above 7 billion, and that it will start to decline very steeply within two decades, leveling out at a billion or so by the end of this century.

In the face of our physical circumstances, it matters not at all which demographic theories you prefer. In the face of overshoot and 10 to 20 year time lines they are all moot.

(Snip more about why there is still reason to hope even in the face of such a dire prediction...)