Demographic Transition Theory – Balancing Births and Deaths
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Please use this space to discuss Paul R. Ehrlich’s MAHB Blog post Demographic Transition Theory – Balancing Births and Deaths. Click on the link below to read more.
Demographic Transition Theory – Balancing Births and Deaths
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As Virginia Abernethy has demonstrated in papers and books, cultural values have a lot to do with the impact of material well-being on TFR. Some examples of the ‘Opportunity Theory” are petrodollar rich arab states whose populations increased dramatically after the export of oil, and the periods after the Irish Famine and French Revolution.
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On behalf of Barry Boulton:
Thanks Paul for continuing to document these issues, and I’d like to comment as follows. As I read these blogs, and as I’ve thought about these issues over time, the question that must and does arise is – what can we do about it? I think that the “shoulds” are at least implicit in the information provided, but in the human sphere, “can do” is always the limiting factor.
Since we can’t impose a population-limiting scheme, and since even limiting social benefits for additional children is politically infeasible, it is likely that only some form of education offers any headway. That is not to assume that education in schools could be effective because if we can’t educate our kids about evolution in that forum, then it’s even less likely that we can educate them to pull back from excess consumption which is our societal norm. Furthermore, if our supposedly rational adult population hasn’t been willing to comprehend healthful eating practices, the notion of educating and changing behavior patterns of the average citizen doesn’t look too good.
I think that economists could offer a pathway to education and action in this way. The standard refrain around the economic world is “how are we going to deal with the costs of a greater proportion of retired; we don’t have enough youngsters to support them”, and “the system is going broke”. The only solutions that our “leaders” seem to comprehend are to increase retirement age, to have more children, and to reduce benefits. In this country the fecundity of recently arrived immigrants might solve the (lack of) young people “problem” for some time, but in other countries it’s a case of incentivizing procreation which is happening as Paul mentions. It’s clear that at some point in time the worldwide economic system must comprehend that population demographics will inevitably be age-heavy. That means developing a new or at least dramatically changed economic paradigm. This is where I see some prospects for a change agent in that a university such as Stanford could set up to encourage world-class (i.e. influential) economists to participate in creating this new paradigm. This is where an institution such as Stanford that has historically provided leaders in the political field could make a major contribution by providing economic advisers to our future Presidents who can speak to a much more sustainable economic paradigm than that is vogue today. We could actually conceptualize an economic system that, rather than being our master, would be a servant to our deeper human needs of fulfillment, satisfaction and so on rather than on simple acquisition of wealth and objects (stuff) along with ego-gratification.
Yes, I know that those human aspects need to be defined and refined in a less “new-age” fashion, and that leads me to another “could do” notion. We need another world-class research project that would consider what it might be to be truly human. That’s a sort of inflammatory statement perhaps, but if we look at current human behavior patterns it’s clear that our primitive survival instincts – often barely camouflaged by modernity – actually prevent our species from being the creative peoples that we could be now that sheer survival is no longer a problem (well, in the long run, it is, but that’s a different reason and principle). It is so ironic that our historical survival needs evolved a creature with such richness potential in cultural realms, a potential that could confer at least some reasonable longevity for our species accompanied by less detriment to other species, and yet never was the old saying about “snatching defeat from the jaws of victory” more sadly appropriate.
There needs to be close collaboration between these two tracks of deeper human needs and economic fulfillment such that it should really be a combined project.
Finally, the question arises as to whether sustainability can come from a “bottom-up” set of actions by people individually and collectively, or a “top-down” leadership approach, and it seems to me that this would be an important discussion topic for MAHB because each requires completely different action strategies to have any worthwhile impact.-Barry Boulton
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Dear Barry Boulton,
I try to write a PhD on the possibility of a green democracy and an eco-meritocracy.
… and am grateful for any input.
Though I truly wish that democracy works and people were a little less selfish and not commodity fetishists, I fear that human nature is the core problems – at least tendencies in human nature.
There are two possible scenarios – both are top down in a sense.
1. The Likely: the catastrophe hits whole humanity (except the super rich) -this (unleashed natural) forces us to have less children and kills millions
2. Somehow somewhere a leadership emerges that practices a rational and consequentialist approach and implement policies that mitigate at least some of the otherwise inevitable.
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On behalf of Max Kummerow:
Demographic transition theory (DTT) doesn’t explain high birth rates in groups like Amish or Mormons or Israeli ultra-orthodox where cultural norms are important. It’s actually a lousy theory. Much more likely that reducing birth rates would reduce infant mortality than the other way around as in DTT. For family size to fall as prosperity increases requires children to be what economists call “inferior goods” meaning higher income causes you to buy less of them. This is not very plausible since we like children. Demographic transitions are not automatic, that is for sure. They have taken intentional actions from individuals and societies to be accomplished.
-Max Kummerow
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On behalf of Thomas Rudel:
A comment and a question – First, the comment. In any forthcoming climate change compact between countries, it would seem reasonable to allow countries to meet their ghg emissions reduction targets through population declines as well as through direct cuts in emissions from the now more energy efficient activities. Countries like Italy, currently slated to see a large population decline over the next 35 years, could achieve a considerable decline in emissions through population declines.
Second, what sorts of effects does immigration have on ghg emissions? The problems of finding younger workers might lead to the easing of some restrictions on in-migration. The arrival of immigrants with higher fertility rates has raised fertility rates in the US, but, thinking about the counterfactual, the move to the wealthier countries should lower fertility rates among the immigrants. What are the net effects on population and on ghg emissions?
Tom Rudel
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I totally agree with Paul Ehrlich that all population numbers must be headed down ASAP. I say this to make it clear that the following criticism of Ehrlich’s “Balancing Births and Deaths” paper is intended to show the flaws with the current wisdom of our population experts. I agree with Ehrlich that the Demographic Transition Theory is totally inadequate to provide hope that we will reduce our numbers via low fertility faster than the environment will reduce our numbers via premature death.
There is a subtle flaw with the following quote that shows a fundamental flaw with the conventional wisdom: “no known society has ever had its birth rate just balance the death rate for a substantial period and thus achieve a steady-state (“stationary”) population.” Ehrlich would have been more accurate if he had said that no known society has ever managed to limit their fertility such that their population remained stable and below the limits of the environment. (The inhabitants of the island of Tikopea in the Pacific as described by Jared Dimond in Collapse is one example of a society that did achieve this).
The human population history is dominated by periods of stable populations within each environment. The individual societies within those environments will grow and shrink over time as they compete among themselves. This stability is provided by the environment. If the environment is stable and the humans make no break throughs in technology, and the environment is large enough to support several societies, then the population numbers in that environment will be stable too. This is because we humans are like every other species in that we are always attempting to drive our numbers to infinity at an exponential rate. The environment stops that attempted growth.
Think of a bucket with a hole in the bottom. The amount of water in the bucket is the population. The water running out that hole represents old age death. Water running over the sides represents child mortality. The rate that we pour water into the bucket is how many children we are averaging. It is trivial to have a stable population, just keep the walls of the bucket at a set height. We humans, and all species, have always poured water into the bucket so fast that the bucket is always full and overflowing.
The flaw with the conventional wisdom is an unrecognized assumption in their thinking. Demographers assume that somehow child mortality is not affected by the birth rate. In a stable environment, and a population that is at the limit, the child mortality rate will be (x-2)/x where x is how many children adults average. (This is like mean water height of an ocean. You will almost never record that number but it must fluctuate around it.) The replacement rate is the child mortality rate, and notice the definition of replacement rate, that Ehrlich refers to in the article, does not attempt to ensure that x is not affecting the child mortality rate. The only way that the birth rate is not affecting the death rate is if the population is not at The Limit of what that environment can provide for or if that population is systematically controlling their fertility. No society, except the Tikopeans and now the Chinese, have controlled their fertility, thus there is no excuse to assume that we are not at The Limit.
There are several contributing factors for why demographers do not comprehend this, but I think the most important factor is that they use birth rate and death rate as defined as births/deaths per 1000. This measure obfuscates the magic number 2. It clouds who must die when we ram our numbers into the limit and continue to crank out babies too fast. Instead, they should use Average Number of Children. This is almost the same numerical value as TFR, but without the complicated definition. Average Number of Children is calculated by asking every adult, right before they die, how many children they created, and averaging that. This definition is easy for everyone to understand. It is trivial for one to determine their contribution and compare that to the magic number 2. This definition flawlessly isolates the deaths that are caused by averaging too many children, and clearly marks those deaths as premature deaths. Children and only children must die if adults average too many babies.
Another reason that demographers don’t recognize this is because there are many examples of societies that reduce their fertility. There are morality rules like, no babies out of wedlock and don’t have one if you are too poor to care for it. These do reduce the child mortality rate from what it otherwise would have been. However, only the Tikopeans put in place the correct morality that will allow them to reduce their fertility such that they knew that they were not suffering child mortality as a consequence of too many births. If I use the bucket/water example, then yes, many societies have reduced the inflow of water, but only the Tikopeans ensured that water was not flowing over the sides.
This must be taught. Every population expert needs to understand this and we need to move this information into the required curriculum for every child in the world.
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One clarification of my last post:
The bucket wall height represents the capacity of the environment. We have raised that capacity throughout the history of humans. When we use farming techniques we have a higher population capacity than when we use hunting/gathering. If we have refrigeration, modern packaging, trucking and fertilizers, we have an even higher capacity. There is no reason to believe we have ever managed to raise the walls of the bucket fast enough to prevent the overflow that must happen when water is poured in too fast. That includes the past 150 or so years when we have seen exponential growth in our numbers.
When the environment is stable, it is trivial for the birth rate and the death rate to be perfectly in sync, just like it is trivial to maintain a set water level in a bucket that has holes in it. Just pour water in faster than it drains out the holes. That’s exactly what is happening and has been happening throughout human history. The theory of evolution demands that every species produces an excess of babies. Ehrlich is incorrect that no society has achieved that perfect balance, because the Tikopeans did it. He is generally correct to say that societies do not achieve this, but this is only because there are multiple societies in every environment that are competing for the resources. If any society had learned what the Tikopeans figured out, they would have been muscled out of existence by their neighbors. The Tikopeans had their own island with one society on it.
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