Population Growth and Trends

Population Growth

• Population growth is always expected to surpass people and countries ability to produce enough food, causing poverty and starvation
• Thomas Robert Malthus, from 1766-1834, wrote about the "Principle of Population"

How Fast is the World's Population Growing?

• Overall, there is an increase in population from 0.3 billion to 9 billion
• From year 0-1800, population gradually/slowly increased from 0.3 billion to 1 billion
• From 1800-2100, the population has been increasing rapidly/drastically from 1 billion to 9 billion
• Fastest population growth rates are in Asia and Africa
• Population decline has been observed in Europe
• Rapid growth of the world population is defined as population explosion
• There are approximately 30 people born every 10 seconds
• Population growth refers to a change in population size, whether positive or negative
• Zero population growth occurs when there is no change in population numbers
• Population growth is uneven across the world, with some areas experiencing faster rates than others

Factors Influencing Population Growth Rates

• Birth rate (BR), death Rate (DR), and migration effects are key factors impacting population growth rates

Population Growth Equation

• Population growth = (Birth Rate - Death Rate) + effects of migration
• Natural increase/decrease affects natural population change
• More inflow relates to more people arriving
• More outflow relates to more people leaving

Birth Rate

• Birth rate is the number of live births for every 1,000 people in a year
• It is usually expressed as, for example, 30 live births per 1,000 people

Death Rate

• Death rate is defined as the number of deaths for every 1,000 people per year
• It is usually expressed as, for example, 30 deaths per 1,000 people

Natural Increase

• If the birth rate is greater than the death rate (BR > DR), there is a natural increase in the country
• In Singapore 2012, the birth rate was 10.1 live births per 1,000 people and the death rate was 4.5 deaths per 1,000 people
• The natural increase was 5.6 per 1,000 people, which is considered low

Natural Decrease

• If the birth rate is less than the death rate (BR < DR), there is a natural decrease in the country
• In Russia in 2005, the birth rate was 9.8 live births per 1,000 people and the death rate was 14.5 deaths per 1,000 people
• The natural decrease was -4.7 per 1,000 people

Infant Mortality Rate

• Infant Mortality Rate is defined as the number of deaths of children less than one year of age per 1,000 live births

Population Trends

• Population trends include time (temporal)/Demographic Transition Model (DTM), space (spatial) and Global population distribution

Demographic Transition Model (DTM)

• The DTM shows population change over time
• The DTM studies how birth rate and death rate affect the total population of a country
• Natural population change only factors birth rate and death rate, migration is not taken into consideration

Stage 1: High Stationary

• High birth rate, high death rate
• Slow population change/increase
• This stage represents pre-industrial societies with low total population due to high birth and death rates
• There is a heavy reliance on agricultural productivity or unskilled manual labor, as larger families meant a larger workforce
• There is a high death rate as countries seeks to achieve or maintain replacement level (total fertility rate at 2.1 births per woman)
• High infant mortality rates and low life expectancy are common, with limited/insufficient medicine and maternal care, and inadequate sanitation and public health
• The total population remains more or less constant

Stage 2: Early Expanding

• High birth rate, low death rate
• Rapid population increase
• Early industrialization leads to a rapid decrease in death rate, while the birth rate remains high
• Decreases in death rate are due to significant improvements in overall health, specifically access to pediatric care, which affects the life expectancy of children
• Advancements in healthcare, education, and technology in food production and sanitation also help lower death rates
• As births surpass deaths and the birth rate remains high, there is a total rise in population

Stage 3: Late Expanding

• Rapidly decreasing birth rate, low death rate
• Rapidly increasing population change
• Death rates are low and birth rates decrease due to improved economic conditions, increased woman's status and education, and access to contraception
• A woman's job is no longer to be a housewife, delayed childbirth
• The pace of total population growth will continue until birth rates are lowered to or below replacement level (total fertility rate at 2.1 births per woman)

Stage 4: Low Stationary

• Low birth rate, low death rate
• Not much population change
• Industrialized developed societies birth and death rates are low
• Decline in birth and death rate due to strong economies, highly educated citizens, ample healthcare systems, and expanded employment opportunities for women
• High total population, but growth rate is gradual/stabilizing

Stage 5: Declining?

• Low birth rate, low death rate
• Natural decrease in population change
• Death rate becomes higher than birth rate
• Economy is the driving force behind further limits on family size and contraception use
• The high costs of raising a family in cities or the enticing opportunities of employment might delay child bearing, birth rates decline well below replacement level (2.1 children per woman)
• This results in an ageing population that will eventually lead to a total decline in population size
• Most LEDCs are at stage 2 or 3 (growing population, high NI)
• Most MEDCs are now at stage 4 of the model, and some, such as Germany, have entered Stage 5

Model Usefulness

• A model is (a) a representation of some phenomenon of the real world made in order to facilitate an understanding of its workings; (b) a simplified and generalized version of real events, from which the incidental details have been removed
• DTM is useful as a framework against which reality can be measured, evaluated, and understood

Global Population Distribution: Population Density

• Population density is defined as the number of people living on a unit area of land
• Population density = (number of people) / area
• To describe population density, categorize as high/low/moderate
  • High: 200-1000+ persons/km²
  • Moderate: 10-199 persons/km²
  • Low: 0-9 persons/km²

Factors Affecting Population Distribution

• Physical environment and climate are factors that explains why some people live where they live
• Climate is defined as rainfall and temperature of a place over a long period of time that determines living conditions and affects agriculture
  • Determines the type of clothes people wear, the kind of structure to live in, and provides food
  • Places that are too hot (e.g., Kalahari Desert) or too cold (e.g., the Arctic) attract fewer people because food sources are scarce
• Relief refers to the height and gradient of ground, affecting drainage and agriculture
  • Steep slopes are unsuitable for cultivation, unless terracing is practiced, potentially leading to lower population density
  • Mountainous regions are inaccessible and make it difficult for habitation potentially leading to low population density
  • Places on higher relief may be safer than lower relief, possibly resulting in higher population density
• Soils
  • Poor soils affect cultivation, especially for agricultural societies, resulting in low population density
  • Soils such as those found in the Ganges-Brahmaputra Delta and Mekong River Delta are fertile, resulting in high population density
• Resources: Water, materials for shelter, food and minerals are basic human needs for survival
  • Areas lacking these resources may experience lower population density, unless technology is used to overcome the shortage
• Level of technology refers to the knowledge, skills, and tools that people use to meet their needs
  • With improvements in technology, environments that were previously unsuitable for living can be converted into suitable living environments
  • For example, people can live in the desert if water can be channeled from a source to their living environment (Las Vegas and canals).