Overview
This lecture reviews the growth of the human population from the origins of modern humans to present day, highlighting important historical milestones and the projected future of population trends.
Human Population Origins and Early Growth
- Modern humans evolved in Africa about 200,000 years ago.
- Around 100,000 years ago, humans began migrating globally.
- Early human population remained below 1 million until the advent of farming.
- Arrival of agriculture led to faster population growth.
Population Milestones Through History
- By AD 1, world population reached about 170 million.
- Population growth was gradual through ancient civilizations (Han Dynasty, Roman Empire, Golden Age of India, Mayan Civilization).
- Notable events: Bubonic plague (1350) led to a rare population decline.
- Technological innovations (gunpowder, compass) coincided with slow but steady increases.
Modern Era Population Boom
- The Industrial Revolution and advances in technology and medicine led to rapid population growth.
- World population reached 1.7 billion by 1910.
- By 2015, population soared to 7.4 billion.
- Current projection for 2050 is 9.5 billion.
Future Trends and Challenges
- Global population is expected to peak around 11 billion by 2100 if current trends continue.
- Fertility rates are dropping worldwide (from 5 babies/woman in 1950 to a projected 2 babies/woman in 2100).
- Small changes in fertility could significantly alter peak population projections.
- Rapid population growth corresponds with increased use of Earth's resources.
Choices Affecting the Future
- Key factors influencing the future include family planning, reduced consumption, pollution controls, and habitat protection.
- The decisions made today will impact both our species and all life on Earth.
Key Terms & Definitions
- Fertility Rate — The average number of children born to a woman over her lifetime.
- Industrial Revolution — A period of rapid industrial growth marked by technological and medical advancements causing fast population increase.
- Bubonic Plague — A major pandemic in the 14th century that caused a significant decline in global population.
- Family Planning — Strategies and methods used to control reproduction and limit population growth.
Action Items / Next Steps
- Review trends in population growth and factors that influence future projections.
- Reflect on personal and societal choices that impact resource use and environmental sustainability.