Chapter 2 — The World Population

Population distribution refers to the way people are spaced over the earth's surface. Broadly, 90 per cent of the world population lives in about 10 per cent of its land area, making global distribution highly uneven.

Density of population = Population ÷ Area, expressed in persons per sq km. For example, a region of 100 sq km with 1,50,000 people has a density of 1,500 persons per sq km.

Four geographical factors: (i) water availability—river valleys are among the most densely populated areas; (ii) landforms—flat plains and gentle slopes are preferred, while mountains are sparsely settled (Ganga plains are dense, Himalayas are sparse); (iii) climate—extreme climates deter settlement while pleasant climates like the Mediterranean attracted people early; (iv) soil fertility—fertile loamy soils support intensive agriculture and denser populations.

Three economic factors: (i) mineral deposits attract industries and skilled workers—Katanga Zambia copper belt in Africa is an example; (ii) urbanisation draws people through better jobs, education, and civic amenities; (iii) industrialisation creates employment for factory workers and service providers—the Kobe-Osaka region of Japan is thickly populated due to its industries.

Push factors make the place of origin less attractive: unemployment, poor living conditions, political turmoil, unpleasant climate, natural disasters, epidemics, and socio-economic backwardness. Pull factors make the destination more attractive: better job opportunities, improved living conditions, peace and stability, security of life and property, and pleasant climate.

Natural Growth = Births − Deaths (ignores migration). Actual Growth = Births − Deaths + In Migration − Out Migration (accounts for all three components of change).

CBR is the number of live births per thousand of population in a year. Formula: CBR = (B ÷ P) × 1000, where B = number of live births during the year and P = estimated mid-year population of the area.

CDR is the number of deaths per thousand of population in a particular year. Formula: CDR = (D ÷ P) × 1000. Mortality rates are affected by the region's demographic structure, social advancement, and levels of economic development.

Stage 1: High fertility and high mortality—people reproduce more to offset deaths due to epidemics and variable food supply; most are in agriculture; life expectancy is low. Stage 2: Fertility remains high initially but declines over time; mortality drops due to improvements in sanitation and health; the gap between the two causes rapid net population addition. Stage 3: Both fertility and mortality decline; population is stable or grows slowly; society is urbanised, literate, and deliberately controls family size.

In his 1798 theory, Malthus stated that the number of people would increase faster than the food supply, and any further increase would result in a population crash caused by famine, disease, and war. He argued that preventive checks are better than physical checks for sustainability of resources.

Demographic transition theory states that any region's population moves from high births and high deaths to low births and low deaths as society progresses from rural, agrarian, and illiterate to urban, industrial, and literate. The stages of this change are collectively called the demographic cycle.

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