Demographic transition theory

Also called: Demographic cycle · Topic: World Population: Distribution, Density, Growth and Migration · NCERT: Class 12, Ch 2 "The World Population: Distribution, Density and Growth"

Meaning

Demographic transition theory says that a region's population moves from high births and high deaths to low births and low deaths as its society changes from rural, agrarian (farming) and illiterate to urban, industrial and literate. It helps us describe a region's population today and predict how it will change. All of these stages taken together are called the demographic cycle (NCERT Fig. 2.2).

Explanation

Key terms and how growth is measured

• Fertility means births. It is measured by the birth rate: births per 1,000 people per year.
• Mortality means deaths. It is measured by the death rate: deaths per 1,000 people per year.
• Natural growth is the birth rate minus the death rate.
• In NCERT Fig. 2.2, the gap between the birth line and the death line shows how fast the population grows.

• A wide gap means fast growth. A narrow gap means slow growth.

• The main idea is that people are flexible. They change how many children they have when their living conditions change.

The three stages (NCERT model)

Stage	Births	Deaths	Growth	Society
First	High	High	Slow	Farming, illiterate, low technology
Second	High at first, then falls	Falls	Highest (population explosion)	Sanitation and health care improve
Third	Low	Low	Stable or slow	Urban, literate, skilled

• First stage: births and deaths are both high, so growth is slow.
• Deaths are high because epidemics (diseases that spread to many people at once) kill many people. The food supply is uncertain, so a bad harvest can bring famine.
• Because of this, life expectancy (the average number of years a person is expected to live) is low.
• Births are high because parents have many children to make up for the ones who die. For farmers, a large family means more hands to work the land.

• About 200 years ago, all countries of the world were in this stage.

• Second stage: deaths fall quickly, but births stay high for a while.

• Better sanitation and health care bring the death rate down.
• Old family habits change slowly, so the birth rate stays high at first.
• The gap between births and deaths becomes very wide. This fast growth is the population explosion.

• Later in this stage, births also start to fall and the gap begins to close.

• Third stage: births and deaths are both low.

• People live in towns, are literate and have technical skills.
• They choose to have small families, so the population is stable or grows slowly.

The five-stage model (beyond NCERT)

Stage	Name	Births	Deaths	Growth
1	High stationary	High	High	Very slow
2	Early expanding	High	Falling fast	Very fast
3	Late expanding	Falling	Low	Slowing
4	Low stationary	Low	Low	Near zero
5	Declining	Below deaths	Low but rising (ageing)	Negative

• Stage 5 (decline): births fall below deaths, so the population shrinks.
• Replacement level is 2.1 births per woman. This is the number of births needed for each generation to replace itself.
• In more than half of all countries, fertility is now below 2.1 [2].
• Nearly one-fifth of countries have "ultra-low" fertility, meaning fewer than 1.4 births per woman (2024) [2].

• In 2024, women had on average one child fewer than in 1990 [2].

• How the transition changes age structure (how a population is split between children, working-age adults and old people):

• Youth bulge (a large share of people aged 15-24 or 15-29) appears in late stage 2 or early stage 3. Deaths fell a few decades ago while births stayed high, so a very large group of children has now grown up.
• Population ageing (a rising share of old people) appears in stages 4-5. Fewer births mean fewer young people, and fewer deaths mean people live longer.
• Population pyramid shapes follow the stages. An expansive pyramid (wide base) belongs to stage 2. A stationary pyramid (bars of about equal width) belongs to stage 4. A constrictive pyramid (narrow base, wide middle and top) belongs to stages 4-5.

Origins and critiques

• Origins:
• Warren Thompson (1929), an American demographer (a person who studies population), grouped countries by their birth and death rates. His grouping was based on about 200 years of change in industrial societies.
• Frank Notestein (1945) turned this into a formal theory and named the stages of "transition".

• Thomas Malthus (1798) came much earlier and gave a different view. He said population grows faster than food, so growth is checked by famine, disease and war. Transition theory says growth slows down on its own as societies develop.

• Critiques:

• It is based on Europe's experience. Other countries may not follow the same path.
• Deaths fell faster in today's poor countries.
  • In Europe, the death rate fell slowly over about 150 years.
  • Asia, Africa and Latin America imported vaccines, antibiotics and DDT after 1945, so their death rates fell within a few decades.
  • Their birth rates stayed high, so the gap was wider than Europe's and their population explosions were bigger.
• Fertility can fall without industrialisation. Kerala and Bangladesh show this.
• It cannot predict well when or why the change happens. Culture, religion and government policy also affect fertility.
• It does not explain stage 5. It cannot say how far below replacement level fertility will fall.

Where it occurs

• All countries: about 200 years ago, every country was in the first stage (NCERT).
• Stage 1 today: no country is in this stage. Only some remote tribal groups are.
• Stage 2 (early expanding): Niger and Chad, and most of sub-Saharan Africa.
• Nine countries, mostly in sub-Saharan Africa, are growing so fast that their populations will double between 2024 and 2054 [2].

• Niger, Nigeria and Pakistan have expansive (wide-based) pyramids.

• Youth bulge: sub-Saharan Africa, Pakistan and Afghanistan.

• Stage 3 (late expanding): India and Bangladesh. NCERT calls this the late second stage.
• India's pyramid has a base that is getting narrower and a bulge in the working ages. India is moving from expansive towards stationary and is in its demographic dividend window.

• Kerala (India) and Bangladesh cut fertility while still mostly rural. The causes were female literacy, health care and family-planning programmes.

• Stage 4 (low stationary): UK and USA. Australia also has a stationary pyramid.

• Stage 5 (declining): Japan, Italy, South Korea and China.
• 63 countries and areas, including China, Germany, Japan and Russia, had already reached their highest population by 2024 [2]. These countries are expected to shrink by about 14% over the next 30 years [2].

• Japan is ageing fastest: about 30% of its people are 65 or older. Italy and South Korea follow.

• World:

• World population was 8.2 billion in 2024 [2].
• It is expected to peak at about 10.3 billion in the mid-2080s and fall slightly to 10.2 billion by 2100 [2].
• Global life expectancy was 73.3 years in 2024, up from 70.9 years during the COVID-19 pandemic [2].

Don't confuse with

• Malthusian theory (1798): Malthus said population growth is checked by famine, disease and war, because population grows faster than food. Transition theory says growth slows down on its own as societies become urban and literate.
• First stage vs second stage: both stages have high births. But growth is slow in the first stage, because deaths are also high. Growth is highest in the second stage, because deaths have fallen.
• Demographic dividend vs youth bulge: a youth bulge is simply a large share of young people. A demographic dividend is the extra economic growth that comes only if those young people have jobs. Without jobs, the same bulge can lead to unrest.
• NCERT three-stage model vs five-stage model: NCERT stops at "low births, low deaths". The five-stage model adds a declining stage (births below deaths), which covers Japan. It also splits the expanding phase, which is why India is "late second stage" in NCERT but "stage 3" in the five-stage model.

Prelims Hooks

• The theory goes back to Warren Thompson (1929) and was made formal by Frank Notestein (1945). It is not from Malthus (1798).
• Highest growth (population explosion) comes in the second stage, not the first. About 200 years ago, all countries were in the first stage (NCERT).
• Five-stage matches: Niger and Chad are in stage 2. India and Bangladesh are in stage 3 (NCERT: late second stage). UK and USA are in stage 4. Japan is in stage 5 (decline).
• Replacement-level fertility is 2.1. Ultra-low fertility is below 1.4, and nearly one-fifth of countries were there in 2024 [2].
• UN WPP 2024: people aged 65+ will outnumber under-18s by the late 2070s, and people aged 80+ will outnumber infants under 1 by the mid-2030s [2]. 63 countries, including China, Japan, Germany and Russia, have already peaked [2].
• Trap: Kerala and Bangladesh cut fertility without industrialisation. Pyramid match: expansive = stage 2, stationary = stage 4, constrictive = stages 4-5.

Mains Points

• Different stages need different policies:
• Countries in stage 2 (sub-Saharan Africa) need girls' education, health care and family planning.
• Countries in stages 4-5 (Japan, Italy, South Korea) need pensions, care for old people, automation and immigration.

• India's large young population helps the economy only if young people have skills and jobs. Without jobs, a youth bulge can lead to unrest, as seen in debates about the Arab Spring (2010-11).

• Critique for "evaluate" questions:

• The model is based on Europe.
• Vaccines, antibiotics and DDT were imported after 1945, so death rates fell fast while birth rates stayed high. This made the gap between births and deaths wider in poor countries than it was in Europe.
• Fertility fell without industrialisation in Kerala and Bangladesh.

• The model has no clear end point once fertility drops far below 2.1, as in the ultra-low fertility countries of 2024 [2].

• Ageing is changing world population patterns:

• 63 countries have already peaked [2], and older people will outnumber children by the late 2070s [2].
• Countries that age fast will depend more on migrants from younger countries. This links the demographic transition to world migration flows.

Related concepts

• First stage of demographic transition
• Second stage of demographic transition
• Third stage of demographic transition
• Youth bulge
• Population ageing

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• Demographic transition theory