The Demographic Transition Model is a model used my demographers to describe the transition form high birth rates and high death rates to low birth rates and low death rates that occurred during industrialization in Western nations. It occurred in four stages. (See “Demographic Transition” chart for reference.)
Stage 2: Death rates began to decline in the late eighteenth century in England and shortly thereafter in other nations undergoing industrialization. Birth rates stayed constant for a while and then began to drop in a pattern similar to death rates. Consequently, even though they were both declining, the fertility rate was significantly higher than the mortality rate in any given year for many decades. This led to a significant increase in the population.
Stage 3: Beginning in the mid to late nineteenth century, death rate declines began to slow and level out. Meanwhile fertility rates continued to decline leveling out at a later date. The population continued to experience significant growth but at an ever declining rate.
Stage 4: Death rates and birth rates stabilized at or below replacement levels in the mid to late twentieth century.
Stage 2 emerged in response to increased agricultural productivity. Improved farming methods and technological innovations played a role. A surplus of food meant that diet improved. This improved health and vigor. It reduced the death rate as people lived longer and people lived more productive lives. With improved health and enough to meet basic subsistence needs, people began to address pollution problems like waste elimination and personal hygiene. This lessened the amount of disease and allowed more people to live longer and more vigorous lives.
Stage 3 was a period where the infant morality rate (children dying before their first birthday) was noticeably lower. Whereas only four or five children out of eight might have lived to adulthood in the past, now seven or eight children might reach maturity. Fewer children were needed to perpetuate the family and birth rates declined. Increased industrialization also meant urbanization and a departure of traditional values about family size and the role of women. Women no longer gained as much status from family. They become more educated and literate, often entering the workforce. This led to greater affluence and greater sophistication in knowing how to create a better quality of life. People become evermore empowered and greater demands were made for environmental improvements and safety.
Stage 4 has seen a stabilization of death and birth rates. Concerns about quality of life issues including pollution and environmental concerns have risen in importance. Some believe there may be a stage 5 in which birth rates stay the same or decline but death rates begin to increase because of decreased physical activity and increasingly unhealthy lifestyles like overeating. Whether this is true and to what degree is a subject of debate.
What does this have to do with environmental concerns? People at or below the subsistence level are oblivious to long term environmental concerns. Most of the people in Stage 1 don’t have the luxury of worrying about deforestation, land erosion, pollution and contaminated water. They need to survive today. As the Demographic Transition starts, there is more despoiling of the environment and there are more people affecting the environment. However, as more people move beyond mere subsistence they begin to raise environmental questions. They become stakeholders in the economy and pollution begins to have an impact on their private property. Demand for pollution solving techniques and technologies increases. The environmental improvements become a contributing factor to extending lives and reducing infant mortality rates. This creates greater affluence which means both larger numbers of educated people who can address quality of life issues and more financial resources with which to address such problems. While there is an increase population, the rate of pollution actually declines. The World Bank believes that pollution increases with economic growth until a society gets to about $3,500 per capita and then, for the reasons just given, per capita pollution declines.
But not only does the quality of life go up and the pollution decline per capita; the productivity per capita increases as well. As a society, people become more and more effective stewards (producers) of the resources. They create ever higher outputs relative to the amount of inputs. It is inaccurate to achieve an estimate of future events by looking at the per capita amounts of consumption and pollution at a point in history and multiplying that by a projected increase in population. Neither can we do this for levels of productivity. Consumption becomes more efficient and less polluting while productivity increases.
Now the really big question is “Well this transition hold true for the rest of the world?” That is a question for legitimate debate. There are no nations remaining in Stage 1 today according to most demographers. Several other nations have gone through the four stages or are near the end of the third stage. The time over which they made the transition has been radically accelerated.
For most Western nations the transition was made over a 150-200 year timeframe. Most nations outside the West were still in Stage 1 by the start of the twentieth century. The big change came as Western nations began to invest large amounts aid in other countries. Vaccinations, health education and introduction of certain technologies made radical improvements. Death rate decreases that took Western nations decades to achieve occurred in less than a decade in some nations. However, birth rates are much more a function of culture decisions than are death rates and they are more resistant to change. Thus, for a time there was a wide disparity between birth rates and death rates leading to an explosion in population. (See the chart about developing nations.) Governments and international organizations invested heavily in family planning training and contraception in efforts to change cultural values about family size, often with mixed success. But over time many nations made the journey toward stage four.
There are, however, nations that have made their way into the second and possibly even third stages and stagnated. These would include some nations in Latin America and Asia, much of Africa and several Mid-Eastern nations. The remaining communist nations like China, North Korea and Cuba also would be included. Why? The initial technological increases have made some initial dents in the death rates but rule of law, market exchange, clear property rights and resistance to culture change with regard to certain cultural values (especially as it relates to women and girls) prevent nations from forming the institutions that will take them down the path to Stage 4. Totalitarian and corrupt governments, ingrained “rent-seeking” mentalities and deeply embedded values about patriarchal domination of women all are contributing factors. Western nations had to overcome some of these same barriers but they had two centuries to work through the transitions. Some of these nations have had this radical change compressed into a timeframe of two generations. One has to wonder if this isn’t one of the contributing factors to the rise of Islamic fundamentalism in recent decades.
It is often said that the world has an over population problem. Overcrowding and population density creates poverty and pollution. I challenge that. Look at the population density of some of the most densely populated nations and their per capita gross domestic product:
Singapore: 16,514 per sq mile; $27,800
Taiwan: 1,648 per sq mile; 25,300
South Korea 1,279 per sq mile; $19,200
Netherlands 1,023 per sq mile; $29,500
Belgium: 879 per sq mile; 30,600
Japan: 873 per sq mile; $29,400
Israel: 783 per sq mile; $20,800
United Kingdom: 639 per sq mile; $29,600
Germany: 598 per sq mile; 28,700
Italy 500 per sq mile; $27,700
Then look at some of the least densely populated nations and their gross domestic product.
Congo: 4 per sq mile; $700
Bolivia: 21 per sq mile; $2,600
Sudan: 42 per sq mile; $1,900
Mozambique: 63 per sq mile; $1,200
Laos: 68 per sq mile; $1,900
Madagascar: 80 per sq mile $800
Cameron: 93 per sq mile; $1,900
Tanzania: 101 per sq mile; $700
Yemen: 102 per sq mile; $800
Nicaragua: 109 per sq mile; $2,300
Population density is not the issue. The issue is rule of law, property rights and market economies. Those nations that have embraced this model have prospered. Those that haven’t, have not. The world could easily support many billions more people if space is the only concern.
The reality is that the world will not need to support many billions more. There are approximately 6.5 billion people living today. The United Nations median population growth scenario projects a population of about 9 billion in 2050, with a leveling or even decline following. Low end projections are at about 7.5 billion. As these figures seem to keep revising downward over the years it seems likely it will top out at 7.5-8.5 billon people. This is hardly a catastrophic number.
The bottom line is that by increasing prosperity throughout the world, you end up with people who produce the greatest amount of output per amount of material and financial input and you get people who become increasingly concerned about cleaning, protecting and maintaining their environment. In other words, you get stewards. We don’t need less people. We need more people to become stewards!
Of course, this begs the question about sufficient energy and material resources and issues like carbon dioxide emissions.