World Population Growth

• Population growth was slow for most of human existence, averaging 0.002% annually, with significant fluctuations due to wars, plagues, famines, and natural disasters.
• Population growth rates have accelerated since approximately 8000 BCE.
• The world population milestones include reaching one billion in the early 19th century, two billion in 1930, three billion in 1960, four billion in 1975, five billion in 1986, six billion in 1998, and seven billion expected in 2013.
• 81% of the world's population resides in Less Developed Countries (LDCs).
• Developed Countries' (DCs) and transitional countries' crude birth rates are no more than 16 per 1,000, while most developing countries have birth rates of at least 25 per 1,000.

World Population Growth

• The world population today is 1,860 times larger than it was 12,000 years ago, around 4 million.
• The world population around 1800 was approximately 1 billion people
• From 10,000 BCE to 1700, the population grew slowly, at an annual rate of 0.04%.
• Since 1800, the world population has increased sevenfold.
• Around 108 billion people have ever lived on Earth.
• Today's population represents 6.5% of the total number of people ever born.
• The UN Population Division provides consistent estimates and projections of population data, updated periodically to reflect changes in fertility, mortality, and international migration, starting from 1950.

Demographic Transition

• The demographic transition involves a shift from a preindustrial, stable population with high birth and death rates to a modern, stable population with low birth and death rates, marked by a period of rapid population growth in between.
• Rapid population increase occurs during the early transitional stage, characterized by high fertility and declining mortality.
• Each stage of the demographic transition is defined by the relationship between birth rates and death rates.
• Social and economic forces influence the progression of countries through these stages.

Stage 1: High Fertility and Mortality

• Stage 1 is characterized by high birth rates and high death rates, resulting in a relatively constant population size, subject to major fluctuations from events such as wars or pandemics, typical before the Industrial Revolution.
• Annual population growth was approximately 5 per 10,000 between 1 and 1650 CE.
• High mortality rates were driven by factors such as the absence of modern sanitation, medicine, industry, agriculture, trade, transportation, and communication.
• Small, self-sufficient socio-economic groups faced severe food shortages due to floods, droughts, insect plagues, and warfare, with inadequate infrastructure to transport surplus food.
• High fertility rates were necessary for survival, supported by prevailing ideologies, values, religion, and social structures that considered large families a blessing.
• Traditional values and institutions supporting high fertility changed slowly as mortality rates declined.

Stage 2: Declining Mortality

• Stage 2 involves declining death rates, particularly among children, due to modern medicine, while birth rates remain high, leading to rapid population growth.
• Many of the least developed countries (LDCs) are currently in Stage 2.
• This stage began in 19th-century Europe as modernization gradually reduced mortality rates.
• Increased food production resulted from improved agricultural techniques, including the introduction of corn and the potato.
• Improvements in trade, transportation, and communication reduced vulnerability to food shortages.
• Declines in deaths from infectious diseases can be attributed to better nutrition and advancements in medical science.
• Improvements in hygiene contributed to mortality rate reduction.
• Mortality rates decreased more rapidly in LDCs than they did historically in developed countries due to the adoption of existing techniques such as improved agriculture, transport, commerce, medicine, and sanitation
• Low death rates in LDCs are possible due to the youthful age structure resulting from birth rates exceeding replacement levels

Stage 3: Declining Fertility

• Stage 3 involves a gradual decrease in birth rates, typically due to improved economic conditions, increased women's status, and access to contraception, leading to continued population growth at a lower rate.
• Most developing countries are currently in Stage 3.
• The decline in fertility in developing countries has followed the decline in mortality more rapidly than it did in Europe.
• Two competing explanations for fertility decline exist, one focused on organized family-planning programs and the other on education, urbanization, modernization, and economic development.
• The total fertility rate (TFR) declined from the 1960s to the 1990s, even in the poorest developing countries, across 113 developing countries, and all 35 developed countries,
• The world's TFR dropped from 4.6 births per woman in 1968 to 2.8 in 2003.
• Family-planning programs involve propaganda and contraceptives to reduce births.
• Economic development, modernization, urbanization, and industrialization also contribute to decreased fertility rates.
• Among developing countries, increased income is associated with lower fertility rates.

Beyond Stage 4: A Stationary Population

• Most developing countries are projected to reach replacement-level fertility between 2020 and 2040
• Population momentum, or continued growth, occurs after replacement-level fertility is reached due to the age structure having a high percentage of women in or below reproductive age.
• Most developing countries will likely achieve a stationary population (zero growth) between 2075 and 2175, approximately 5 to 14 decades after reaching replacement level.

Explore the history and trends of world population growth. From slow growth rates to more rapid increases, this lesson covers key milestones and factors influencing population changes. It also contrasts birth rates in developed and developing countries.