In which stages of the demographic transition is the rate of natural increase low?

The Demographic Transition Model was developed by the American demographer Warren Thompson in 1929. DTM depicts the demographic history of a country. It refers to the transition from high birth and high death rates to low birth and low death rates regime as a country develops from a pre-industrial to an industrialized economic system.

The five stages of the demographic transition model

Stage One: The Pre-Industrial Stage (highly fluctuating – high stationary)

• Both birth rate and death rate are high
• Population fluctuates due to incidence of famine, disease and war.
• High infant mortality and very low life expectancy.
• Rural societies dependent on subsistence agriculture.
• Total population is low and balanced due to high birth rates and high death rates.

Example: No country as a whole at present retains the characteristics of stage 1. However, it applies only to the most remote societies on earth such as the isolated tribes in Amazon with little or no contact with the outside world.
All human populations are believed to have had this stage until the late 18th century, when many countries in Western Europe were able to cross this stage.

Stage Two: The Industrial Revolution (early expanding) –very rapid increase

• Death rate falls sharply due to improvements in health care and sanitation. Birth rates remain high. Total population grows very quickly.
• Improvement in farming technology and increase in food supply
• Better nutrition, water supply, sewage, and personal hygiene and improvement in public health system .
• Increase in female literacy combined with public health education programs

Example: poorest developing countries like Afghanistan, Pakistan, Bolivia, sub-Saharan countries such as Niger, Uganda and middle east countries like Yemen, Palestinian Territories are still in stage 2.

Stage Three: Post-Industrial Revolution (late expanding) –increase slows down

• Birth rate falls due to the availability of contraception.
• Reduction of child labour- fewer children being needed to work in farm due to mechanization of farming
• Death rate stays at low level due to improved health conditions
• An increase in the status and education of women
• Total population still rises rapidly due to population momentum.
• The gap between birth and death rates narrows down

Example: Most developing countries that have registered significant social and economic advances are in stage 3, such as Costa Rica, Panama, Jamaica, Mexico, Colombia, Ecuador, Philippines, Indonesia, Malaysia, Sri Lanka, Turkey, Azerbaijan, Turkmenistan, Uzbekistan, Egypt, Tunisia, Algeria, Morocco, Lebanon, South Africa, India.
On the way:South Africa, Zimbabwe, Botswana, Swaziland, Lesotho, Namibia, Kenya and Ghana have begun to move into stage 3

Stage Four: Stabilization (low stationary) – very slow increase

• Birth control is widely available and there is a desire for smaller families.
• Both birth and death rate are low
• Total population is still high, but it is balanced by a low birth rate and a low death rate.

Example: Newly industrialized countries such as South Korea and Taiwan have just entered stage 4.United States, Canada, Argentina, Australia, New Zealand, most of Europe, Bahamas, Puerto Rico, Trinidad and Tobago, Brazil, Singapore, Iran, China, Turkey, Thailand and Mauritius

Stage Five: Declining population

• Low birth rate along with an aging population leads to declining population
• Death rates may remain consistently low or increase slightly due to increases in lifestyle diseases like obesity, stress and diabetic.
• Birth rates may drop to well below replacement level

Example:  Countries like Germany, Italy, Japan, Russia leading to a shrinking population

What happens to birth and death rates?
As populations move through the stages of the model, the gap between birth rate and death rate first widens, then narrows. In stage 1 the two rates are balanced. In stage 2 they diverge, as the death rate falls relative to the birth rate. In stage 3 they converge again, as the birth rate falls relative to the death rate. Finally in stage 4 the death and birth rates are balanced again but at a much lower level.

Demographic Transition Model

Definition: The Demographic Transition Model (apprev. DTM) has five stages that can be used to explain population increases or decreases. The DTM is a key tool for understanding global and regional population dynamics. You need to be able to recognize the 5 stages of the DTM when looking at a population pyramid.

Stage 1

Stage one of the DTM has a high birth rate and a high death rate. Because of this the natural increase rate is close to zero. Zero population growth is when the crude birth rate and crude death rate are equal and the population remains the same. The birth rate and the death rate are both high and equal each other out.

No official country in the world is currently in stage 1. There may be small communities of humans that are in stage 1 of the DTM. Some Indigenous groups in the Amazon or Sub-Saharan Africa that are in stage one, but not all pre-contact Indigenous peoples have high birth rates and high death rates.

For most of human history, the entire world was in stage one. For example, 30,000 years ago, the life expectancy of humans was around 30 years. Remember that it took the world about 100,000 years to reach one billion people! 

Stage 2

Stage two is the early expanding stage where population begins to rise. It has a high birth rate, but the death rate drops. Because of this the natural increase in population rate goes way up! Infant death rates are often high in stage 2 communities but people who do survive birth live longer. A key feature of stage 2 of the Demographic Transition Model is the emergence of grandparents. Longer life expectancies allow for 3 generations to share a part of their live spans. Grandparents are part of every stage of the DTM, but will be more rare in societies with shorter life expectancies.

Identify stage 2 of the DTM on a population pyramid. A number of countries in Sub-Saharan Africa (Niger, Democratic Republic of the Congo, Somalia) are currently in stage two. This is the population pyramid for Niger from 2019. The population of of Stage 2 countries is rising and their doubling time is short. However, the population will not continue to go up at the same rate.

The population pyramids of these countries have a very wide base that gets thinner and thinner the higher you go.

Stage 3

Stage three is the late expanding stage. The birth rate goes down, while the death rate remains low. The population continues to grow, but not nearly as quickly as stage two because low births and low deaths are at equilibrium. The natural increase rate is still positive, but not as high as in stage two.

More adults often means more workers. Stage three countries start to become more industrialized, which means they are more urbanized and the total fertility rate goes down. Countries that are currently in stage three are Mexico, India, Colombia, and South Africa.

The population pyramids of these countries are wider in the middle ages and have more of a pear shape.

Stage 4

Stage four is the low stationary phase. With countries in stage 4 the birth rates get lower, while death rates start to rise as people are getting older. The natural increase rates (NIR) in these countries is close to zero.

For example, in the United States the NIR would be zero if you took away the net-in migration that it has every year. Other countries currently in stage four are China, Brazil, and Argentina.

The population pyramids of these countries are even throughout the age groups and somewhat resembles a skyscraper.

Stage 5

Stage five countries the birth rates remain low, and the death rates go up. Because of this, countries have a negative NIR, which leads to the population decreasing. These countries have graying populations, with less men and women in their childbearing years.

Countries currently in stage five are Japan and a number in Eastern Europe (Germany, Estonia, Ukraine). Fewer young adults are having children. Some stage 5 governments promote pro-natalist policies to try and stunt the population decrease by incentivizing having children.

The

population pyramids in these countries are wider at the top and start to look like an upside down pyramid.

Resources:

Epidemiological Transition Model

The ETM describes causes of death in each stage of the DTM. The Epidemiological Transition Model focuses on why death rates are high or low.

Stage 1

Most people die because of pandemics, like infectious and parasitic diseases (the Black Plague and Malaria).

They will also die because of environmental factors like drought, earthquakes, floods, and also things like starvation and malnutrition. More infants die overall.

Stage 2

People begin to live longer because of change in conditions. Changes that can move a society from stage 1 to stage 2 are improved nutrition, breakthroughs in medicine, end to warfare, and/or improved sanitation. In this stage, not as many people die of infectious diseases because of

, which is the branch of science that studies disease, the causes and cures.

Because of better infrastructure (hospitals, sewers, better plumbing) less people die of parasitic diseases.

Stage 3

People are living much longer. However, chronic diseases associated with age become a challenge. Things like cancer and heart disease are the leading causes of death. 

Stage 4

People are still living longer, but because of better healthcare, treatments, and medical technology people are able to survive cancer and heart disease. 

Stage 5

Stage five has the highest death rates because the population is older. This leads to a negative NIR.

Experts cite three different reasons for this.

The first is disease evolution. Infectious diseases have evolved and established resistance to drugs and other treatments.

The second is poverty. Even the most modern societies have homelessness and poverty. Infectious diseases spread more easily in these pockets of society.

The last is increased connections. Through air travel, trains, highways the world is more connected than ever. Because of this, diseases like AIDS, which spread from person to person via blood or sexual fluids, can be unknowingly spread around the world.

Resources:

Which stage of the DTM has the lowest rate of natural increase?

What is Stage 4 demographic transition?

What happens in stage 2 of the demographic transition?

What happens in Stage 3 of the demographic transition?