World Population & Human Settlements – NDA Geography Notes

The Earth currently supports about 8 billion people, and that number continues to grow, though at a slowing rate. These people are not evenly distributed. Some parts of the world, river valleys, coastal plains, fertile agricultural regions, are densely packed. Other parts, deserts, high mountains, dense rainforests, polar regions, are almost empty.

For NDA, this chapter is lightly to moderately tested. Questions tend to be conceptual: what is physiological density, what does the demographic transition model describe, what is demographic dividend, what kinds of settlements are found in deltas, and where specific nomadic groups live.

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World Population Distribution

About 90% of the world’s population lives in the Northern Hemisphere.

Most densely populated regions: East Asia (China, Japan, South Korea) | South Asia (India, Bangladesh, Pakistan), one of the most densely populated regions on Earth | Southeast Asia (Java, Philippines, Vietnam) | Western Europe | Eastern North America.

Sparsely populated regions: Polar and sub-polar regions (too cold) | Tropical rainforests (difficult to farm) | Deserts (too dry) | High mountain ranges (too rugged and cold).

Why South and Southeast Asia have the largest concentration of peasant population: Because intensive subsistence farming is practised in the region. The fertile river valleys and deltas support intensive wet rice cultivation which requires large amounts of labour per unit of land, creating extremely dense rural populations.

Half of the world’s population lives in just six countries: China, India, United States, Indonesia, Brazil, Pakistan.

Sex ratio: at the world level, there are about 102 males per 100 females. In Asia, sex ratio is low (fewer females relative to males due to son preference in some countries). The statement that Asia has a HIGH sex ratio is incorrect.

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Types of Population Density

★ IMPORTANT All three density definitions have been confirmed correct in NDA 2022-II. [NDA 2022-II]

Arithmetic (Crude) Density = Total population ÷ Total land area. The simplest and most commonly used measure. Can be misleading. Egypt has a lot of desert, so crude density underestimates how crowded the inhabited Nile Valley actually is.

Physiological Density = Total population ÷ Cultivable (arable) land area. Measures how many people each unit of farmable land must support. Gives a better picture of agricultural pressure. Physiological density is preferable to arithmetic density as an index of population pressure on resources, because physiological density uses arable land rather than total area. [NDA 2022-II]

Agricultural Density = Agricultural population ÷ Cultivable land area. Measures the number of agricultural workers per unit of arable land. [NDA 2022-II]

Density Type	Formula	What It Shows	NDA Tag
Arithmetic (Crude)	Total population ÷ Total area	Simple overall density	[NDA 2022-II]
Physiological	Total population ÷ Arable area	Pressure on farmland (most meaningful)	[NDA 2022-II]
Agricultural	Agricultural population ÷ Arable area	Farming labour pressure	[NDA 2022-II]

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Population Calculation

End of year population = Initial population + Births − Deaths + Immigration − Emigration [NDA 2014-II]

NDA 2014-II example: Beginning population = 5,000. Births = 250. Deaths = 60. Immigration = 30. Emigration = 15.

End of year population = 5,000 + 250 − 60 + 30 − 15 = 5,205.

All four components (births, deaths, immigration, emigration) must be included. Students often forget to include immigration and emigration.

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The Demographic Transition Model

The Demographic Transition Model (DTM) describes how a country’s birth rates and death rates change as it develops economically. The DTM provides a model for examining the relationship between economic development and natural population change. [NDA 2015-I]

Stage	Birth Rate	Death Rate	Growth Rate	Description
Stage 1	High	High	LOW (balance)	Pre-industrial; high disease/famine mortality
Stage 2	High	Falls rapidly	HIGH (explosive)	Medicine and sanitation improve; births stay high
Stage 3	Begins to fall	Low	Slowing	Urbanisation, education, contraception
Stage 4	Low	Low	LOW (near zero)	Post-industrial; most developed countries

Stage 2 is the stage of explosive population growth. The gap between still-high birth rates and rapidly falling death rates is the largest. Most developing countries were in or passing through Stage 2 in the 20th century.

Demographic gap = the difference between the birth rate and the death rate, which determines the natural rate of population growth.

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Demographic Dividend

Demographic dividend refers to the economic growth potential that arises when a country’s working-age population (15–64 years) is large relative to the dependent population (children below 15 and elderly above 64).

When a country transitions from high to lower birth rates, a window exists when the working-age population is large (people born during the high birth rate era have grown up as adults) while the number of young children is falling. This creates a window for economic growth: more workers, fewer dependents.

Demographic dividend = large WORKING-AGE population. It does NOT refer to a large elderly population. That is a demographic burden, not a dividend.

India is currently experiencing its demographic dividend: a large young working-age population that, if properly skilled and employed, can drive significant economic growth.

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Population Pyramid

A population pyramid is a graphical representation of a population’s age and sex structure. It shows the proportion of males and females in different age groups.

Variables displayed: age groups AND sex indicators (male and female).

Types of population pyramids: Broad base + narrow top = young population; high birth rate; developing countries | Uniform/Rectangular = stable population | Narrow base + broader middle = aging population; low birth rate; developed countries.

Primate City: the concept developed by Mark Jefferson: the idea that in many countries the largest city is disproportionately large compared to the second city. Examples: Bangkok (Thailand), Lima (Peru), Nairobi (Kenya).

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Human Settlements

A settlement is any place where people live, from an isolated farmhouse to a megacity. Two main types:

Rural settlements: villages and hamlets; dependent on agriculture and natural resources.

Urban settlements: towns and cities; dependent on industry, trade, and services.

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Types of Rural Settlements

Clustered (Nucleated) Settlement: houses grouped closely together. Common in agricultural plains. Most common settlement type globally.

Dispersed Settlement: houses spread far apart. Common where people need large landholdings (pastoral farming) or in difficult terrain.

Linear Settlement: houses arranged in a line along a road, river, or coast.

Dry Point Settlements: settlements located on elevated ground to avoid flooding: in areas prone to waterlogging such as river floodplains and coastal marshes. People deliberately settled on higher, drier spots to avoid floods while maintaining access to water and fertile farmland.

Dry point settlements are common in DELTAS. [NDA 2009-I]

The “dry” in dry point settlements refers to being elevated and protected from floods, NOT a location in a dry desert.

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Important World Cities on Rivers

Montreal: located on the banks of the River St Lawrence in Canada.

Buenos Aires and Montevideo: situated across the banks of the River Plate (Río de la Plata): the wide estuary between Argentina and Uruguay.

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Pastoral Nomads

NDA directly tests which nomadic group lives where:

Group	Location	Environment	NDA Tag
Tuareg	Sahara Desert (Mali, Niger, Algeria, Libya)	Hot desert	[NDA 2014-I]
Yakuts (Sakha)	Siberia, Russia	Tundra	[NDA 2015-I]
Sami (Lapps)	Lapland, Scandinavia	Sub-Arctic	—

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