Population Geography - Study Notes
Lesson summary
About 3,60,000 people are born every day, four births every second. Demography is the statistical study of human population: its size, structure and distribution and its changes through birth, migration, aging and death. Population explosion is one of the greatest challenges we face today.
Distribution of world population
- Relief: rugged mountains support few people; fertile lowlands such as the Ganges and Brahmaputra, the Hwang-Ho and the plains of NW Europe and the USA are crowded.
- Accessibility: areas linked by road, rail, shipping, canals and air are denser; islands were once uninhabited for lack of water transport.
- Adequate water supply: the well-watered Great Northern Plains of India are dense; the drought-prone Sahara is sparse.
- Soil: fertile alluvial soils of the Ganges, Indus and Hwang-Ho valleys support dense population.
- Economic and political factors: unemployment, religious intolerance, conflicts and wars do not favour population.
The ten most populous countries together hold nearly 60% of the world's population.
Density of population
Density = total population / total area of the country (persons per sq.km). Physiological or nutritional density = total population / total cropped area. World arable land is 13.3% and nutritional density 325 per sq.km; India's arable land is 48.83% and nutritional density 753 per sq.km; Singapore has the highest nutritional density.
| Density | Persons per sq.km | Areas |
|---|---|---|
| High | More than 100 | Eastern Asia, Southern Asia, NE USA, Central and NW Europe |
| Moderate | 10 to 80 | Central USA, Tropical W Africa, W Russia, E Europe, Deccan Plateau, Central China, S Mexico plateau, NE Brazil, Central Chile |
| Low | Less than 10 | Amazon and Congo forests, Arctic and polar lands, great deserts, high mountains, Antarctica |
Australia averages 2 persons per sq.km. Reasons for low density: unfavourable environment, lack of economic activities, lack of transport and communication, and government policy.
Terms related to population
- Crude birth rate: live births per 1000 people in a year; crude death rate: deaths per 1000 people in a year.
- Net migration rate: N = 1000 x (I - E) / P.
- Fertility rate: highest in Niger (6.49), lowest in Singapore (0.83).
- Dependency ratio: dependants (under 15 and over 65) divided by the working-age population (15-64).
- Growth rate: (CBR - CDR +/- net migration) / 1000; highest in South Sudan, 3.83% in 2017.
- RNI: CBR - CDR, with no migration.
- Literacy and life expectancy: Burkina Faso has the lowest literacy rate (21.8%, 2015); Monaco the highest life expectancy (89.52 years) and Chad the lowest (49.81).
Growth of world population
- About 8 million when agriculture began 8,000-12,000 years ago; 550 million around 1750; 7.6 billion now.
- Projected 8.6 billion in 2030, 9.7 billion in 2050 and 11.2 billion in 2100; about 83 million added every year.
- China (1.4 billion, 19%) and India (1.3 billion, 18%) are the most populous; India is expected to pass China around 2024. Nigeria, now 7th, should pass the USA to become third before 2050.
- Milestones: 6 billion on 12 October 1999 (Day of 6 Billion); 7 billion on 31 October 2011.
- Doubling time by the Rule of 70: 70 / growth rate. At 2.08%, 70 / 2.08 = 33.6 years. World population doubled in 40 years, from 3 billion in 1959 to 6 billion in 1999.
| Growth | Examples |
|---|---|
| Low | US, Canada, Japan, Australia, New Zealand, Western Europe |
| Moderate (about 2%) | Pakistan, Afghanistan, Brazil, Bolivia, Mongolia, Indonesia |
| High (about 3%) | Mexico, Iran, Colombia, Venezuela, Peru, Libya, Algeria, Sudan, Kenya, Kuwait |
India fact file: 1,363,413,725 people (Feb 2019), 17.74% of the world, rank 2, density 455 per sq.km, 33.6% urban. Over population exceeds resources, under population falls short of them, and optimum population matches them.
Composition of population
- Sex ratio: India 933 females per 1000 males (2011); Kerala highest, then Puducherry (1037) and Tamil Nadu (996). Qatar has 315 males per 100 females; Latvia has 84.8 males per 100 females (2015).
- Literacy: India 74.04%; Kerala 93.91%; Bihar lowest at 63.82%; Tripura now highest at 94.65%. Six states (UP, Bihar, MP, Rajasthan, AP, West Bengal) hold about 70% of illiterates.
- Age-sex pyramids: expansive (more young people, high fertility; Bangladesh, Afghanistan, Kenya), constrictive (narrow base, declining birth rate; USA), stationary (equal shares, stable; Austria).
Migration
- Immigration (in-migration) raises growth; emigration (out-migration) lowers it in the source region. Mexico has the largest number of emigrants; in 2013 the USA, Germany and Russia had the most immigrants.
- Types: net, international, internal, local (within a state or district), voluntary (most migration) and involuntary (forced, mostly slavery; about 11 million African slaves taken to the Americas, 1519-1867).
- Brain drain: the receiving country gains qualified labour; the country of origin loses leaders and talent and is not repaid education and health costs.
- Push factors (unemployment, famine, persecution, disasters) relate to the country left; pull factors (jobs, education, security, family links) to the country of arrival.
Overpopulation and its control
Overpopulation means population exceeding the carrying capacity of the ecological setting, driven by immigration, falling mortality, medical breakthroughs and rising birth rates.
- Depletion of natural resources
- Accelerated habitat loss: rainforests down from 14% to about 6% of the earth's surface
- Amplified climate change and global warming
- Loss of biodiversity
- Decrease of fresh water: less than 1% readily accessible
- Lower life expectancy and diminished quality of life
- Rise in unemployment, crime rate and violence
- Increased intensive farming
Measures: awareness campaigns, promoting adoption, single-child families, treating it as a national security issue, changing social norms, and tax benefits or concessions.
Exam tips
- Nutritional density uses cropped area, not total area.
- In brain drain, the country of origin loses talent.
- Learn one example country for each pyramid type.