Population Growth and Resources

• Unit one focuses on population

Essential Questions

• Is there a limit to the number of living things the Earth can sustain?
• What causes the population of a place to grow or decrease?
• Should population growth be controlled?

Population Growth and Resources

• The population is approaching nine billion, increasing the need to expand land for living space and food, potentially through deforestation
• Reducing meat consumption in developed countries could help feed the global population
• Poverty and starvation result from population growth exceeding countries' ability to produce enough food
• Population may return to a stable state through such elimination
• Thomas Robert Malthus theorized that the world's population increases geometrically
• He also believed that food resources increase arithmetically, leading to overpopulation
• Human population could exceed its food sources
• This could potentially lead to a population crash from famine or disease

World Population Trends

• The world population has increased from 0.4 billion to 9 billion
• The population increased gradually from year 0 to 1800, from 0.4 billion to 1 billion
• From 1800-2100 the population has been increasing rapidly/drastically to 9 billion

Population Explosion

• A population explosion is defined as the rapid growth of the world population
• The world population increases by 30 people every 10 seconds

Rate of Growth

• Asia, followed by Africa and Latin America, experiences the fastest rate of population growth

Population Growth Defined

• Population growth refers to a change in population size
• It can be positive or negative
• No change in population numbers is known as zero population growth
• Population growth is uneven across the world
• Some areas have a faster rate of population growth than others (Asia, Africa, Latin America)

Population Factors

• Population growth is determined by the equation (Birth Rate - Death Rate) + Effect of Migration
• You need to know the definition of birth rate (BR), death rate (DR), and natural increase (NI)/natural decrease (ND)
• Birth rate is the number of live births for every 1,000 people in a year
• Death rate is the number of deaths for every 1,000 people per year

Birth Rate (BR) Examples

• Highest BRs in the world for 2021 were Niger (44.6), Central African Republic (42.3), Chad (42.1), Somalia (42.1), and Democratic Republic of Congo (41.1) per 1,000
• Lowest BRs in the world for 2021 were Vatican City (4.6), Hong Kong (5.4), South Korea (5.6), Ukraine (5.8), San Marino (5.9), and Singapore (7.1) per 1,000

Death Rate (DR) Examples

• Highest DRs in the world for 2024 were Ukraine (18.6), Lithuania (15.2), Serbia (14.9), Latvia (14.7), and Romania (14.6) per 1,000

Natural Increase and Decrease

• Natural increase: When the birth rate is more than the death rate
• Natural decrease: When the birth rate is less than the death rate
• Singapore (2012): BR = 10.1, DR = 4.5, NI = 5.6 per 1000 people (considered low)
• Russia (2005): BR = 9.8, DR = 14.5, ND = 4.7 per 1000 people or NI = -4.7 per 1000 people

Infant Mortality Rate

• Infant mortality rate (IMR) is defined as the number of deaths of children less than one year of age per 1,000 live births
• Afghanistan tops the world for highest IMR with 101.3
• Solvenia is among the lowest IMR with 1.5

Population Change Calculation Examples

• Malta: Birth rate 10.3, death rate 8.3, net migration +2.0; Natural population change: 2.0 per 1000, Overall population change: 4.0 per 1000 or 0.4%
• Bulgaria: Birth rate 9.1, death rate 14.4, net migration -0.3; Natural population change: -5.3 per 1000, Overall population change: -5.6 per 1000 or -5.6%
• Poland: Birth rate 10.0, death rate 9.9, net migration -0.5; Natural population change: 0.1 per 1000, Overall population change: -0.4 per 1000

Population Trends

• Examining how population has changed over time (temporal) and space (spatial)
• Temporal includes the Demographic Transition Model
• Spatial includes global population distribution

Demographic Transition Model (DTM)

• Shows population change over time.
• Studies how birth and death rates affect the total population of a country

Stage 1 DTM: High Stationary

• Pre-industrial society with low population due to high birth and death rates
• High birth rate is due to reliance on agricultural productivity or unskilled manual labor
• Larger families mean a larger workforce
• High death rate is from high infant mortality rate (IMR) and low life expectancy
• The total population remains more or less constant

Stage 2 DTM: Early Expanding

• Early industrialization era with a rapid decrease in death rate while the birth rate remains high
• Decreased death rate is due to significant improvements in health, specifically access to paediatric care
• Improvements in food production, sanitation and education decrease death rate
• Total population will rise because births outnumber deaths

Stage 3 DTM: Late Expanding

• Death rates are low and birth rates decrease
• Improved economic conditions, increase in women's status and education, and access to contraception
• Total population growth is slow, a result of lowered birth rates

Stage 4 DTM: Low Stationary

• Industrialized developed society where birth and death rates are low
• Decline in birth and death rates is due to strong economies, highly educated citizens
• The total population is high, but the growth rate is gradual/stabilizing

Stage 5 DTM: Declining

• Death rate becomes higher than the birth rate
• The economy and family size lead to the increased use of contraception
• Could be due to the high costs of raising a family in cities or the enticing opportunities of employment
• Birth rates decline below replacement level (2.1 children per woman)
• Results in a total loss to the total population size

DTM Modern

• LEDCs are at stage 2 or 3 with a growing population and a high natural increase
• MEDCs are now at stage 4 of the model and some, such as Germany, have entered stage 5

DTM Usefulness

• Based on observations of DCs in the 18th and 19th Century
• Based on Britain's experience from 1066 to 1990s
• A model is (a) a representation of some phenomenon of the real world that facilitates understanding and is described as (b) a simplified and generalized version of real events

Population Density

• Defined as the number of people living on a unit area of land
• Equation is: population density = number of people / area
• To describe population density, we use high/low/moderate

High Population Density

• More than 200 persons / km2

Moderate Population Density

• 10 - 199 persons / km2

Low Population Density

• 0-9 persons / km2

Population Density Examples

• Singapore: 5,535,000 people in 707 km² = 7830 persons/km² (High)
• USA: 321,418,820 people in 9,147,420 km² = 35.1 persons/km² (Moderate)
• Singapore has a higher population density than the USA because Singapore has a smaller land area with a high population

Singapore Population

• How does Singapore support a high population density?
• Singapore has tall public housing
• 85% of Singaporeans live in HDB flats

Factors Affecting Population Distribution

• Physical environment is a factor that explains why people live where they live

Climate

• Climate, defined as rainfall and temperature, determines both living conditions and agriculture
• Physical factors like Climate, Relief and Soils affect society
• Places too hot (Kalahari desert) or too cold (Arctic) attract fewer people to live there

Relief

• Relief is defined as the height and gradient of ground
• It affects drainage and agriculture
• Mountainous regions are inaccessible, resulting in lower population density
• Places on higher relief may have higher population density for safety

Soils

• Soils are a physical feature that affects society
• Poor soils create low population
• Ganges and Mekong river Deltas are fertile and therefore attract high populations

Resources

• Resources include water, materials for shelter, food and minerals
• Without these, expect population density to be lower, unless technology is used to overcome the shortage

Level of Technology

• Level of technology also determines population
• The knowledge, skills, and tools used to meet people's needs
• With improvements in technology, environments which were previously unsuitable for living can be converted into suitable living environments
• Example: can live in the desert with channeled water
• Las Vegas, a city in a desert region, has channeled water via pipes and canals