Unit 3 Managing human population

Population density calculation

total population/land area = # of ppl per km²

Low population density means…

low marriage (low birth rate), fewer jobs in rural areas (causes urbanisation), lack of available healthcare

Intrinsic growth rate

dN/N₀

• dN = (births + immigration) - (deaths + emigration)

• N₀ = original population

Doubling time

• period of time required for a population to double in size

  • Rule of 70: 70/percent

Environmental factors that influence population density & distribution

• natural resources, geographic & climatic factors

  • Large, flat lowland plains are easier to access + better for food production than mountainous areas

  • Areas w/ few extreme weather events are more appealing

  • Areas w/ fertile soil like river deltas tend to have higher populations than areas with high rainfall (leached soil) & cold areas with permafrost

  • A secure water supply

  • Areas w/ a wealth of natural resources

Economic factors that influence population density & distribution

• Agriculture is a primary industry & is manufactured by a secondary industry

  • These increase job opportunities & standard of living, causing population growth

• Areas w/ good transport links are often more densely populated due to trade links

Political factors that influence population density & distribution

• Government policies have an impact on population density

  • Can encourage/discourage investment in an area

  • War is a ‘push’ factor & causes out migration + decrease in food production

Population change

number of people between the start and end of a given time period

Birth rate

number of live births per thousand ppl in a population per year

• High birth rate = increased population & vice-versa

• High infant mortality rate in LICs → high birth rates

  • Due to: spread of disease & lack of both medical care + access to clean water

Death rate

number of deaths per thousand ppl in a population per year

• Influenced by: climate, medical facilities, living standards, & social conflict + crime rates

Life expectancy

increases due to:

• increased standards of living

• access to both clean water & nutrition

• education improvements

Overall population change

• annual population change of an area

  • (birth rate - death rate) + net migration

Stage 1 pyramid

pre-industrial

• high birth & death rate w/stable population

  • Rarely found & low life expectancy

Stage 2 pyramid

transitional

• declining death rate (due to medicine, better nutrition, & clean water)

Stage 3 pyramid

industrial

• birth rate declines from stage 2, death is still declining/low

  • Less population growth than stage 2; birth rates can typically be controlled by contraceptives

  • Avg. life expectancy increases & mortality rates stabilize

Stage 4 pyramid

late-industrial

• low birth & death rates

  • Population size fluctuates due to economic conditions; slow growth

Stage 5 pyramid

post-industrial

• birth rate is lower than death rate

  • Older population reaches full life expectancy

Dependency ratio

relationship between a country’s working & non-working populations

Dependent ages

ages 0 to 14 (young)& 65+ (old)

Independent ages

ages 15-64

Total dependency ratio

[young population (0 to 14) + old population (65+)] × 100 / population aged 15 to 64

• Expressed as # of dependents per hundred ppl in the workforce

• Considered high when it’s above 62%

Dependency ratio decreases due to…

young population reaching working age, anti-natalist policy, immigration of working age ppl, & lower birth rate

Ageing populations

population with a high percentage of older people

Ageing populations…

• Occur when birth rates decline & life expectancy increases — typically stage 5

• Average age is increasing due to: better nutrition, sanitation, standard of living, & care

Impacts of an ageing population

• Shrinking workforce impact economy

• Pensions may be insufficient to care for older populations - higher spending

• Health care systems have more pressure since older ppl need more care

• Increased retirement age, so gov’ts can collect extra taxes

Global organizations to help manage human population change

• The Club of Rome: aims to alert the world about consequences of a rapidly growing population → focused on sustainable economic growth + limited population growth

• UN Agenda 21: plan of action to limit human impact on the environment

• Both are concerned w/ issues related to human population growth

Government policies to help manage human population change

• Pro-natalist: encourage ppl to have children & increase birth rates

• Anti-natalist: discourage ppl from having children & decrease birth rates

  • Other policies include:

    • encouraging marriage later in life

    • increasing access to contraceptives & family planning

    • improving education + employment opportunities for women

    • making abortions legal + safe

Pro-natalist policies

• Shrinking populations pressure a country’s workforce + financial stability

• Monetary incentives, childcare assistance, free schooling, & monthly grants

Anti-natalist policies

• Increasing populations that cause declining mortality rates & high rates of poverty

• e.g) China’s One Child Policy

Limitations as a population stabilizes

• Limitations as a population stabilizes: an ageing population + declining workforce