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Understanding Global Population Changes: Rates, Trends, and Implications

This overview explores the key measures of population change worldwide: Crude Birth Rate (CBR), Crude Death Rate (CDR), and Natural Increase Rate (NIR). It discusses why these metrics are essential for understanding population dynamics, estimating how fast populations are growing, and predicting future trends. With an emphasis on the impact of population surges in Less Developed Countries (LDCs) and varying fertility rates across regions, the text highlights the significance of mortality rates and how they reflect societal health. This analysis is crucial for grasping current and future global population challenges.

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Understanding Global Population Changes: Rates, Trends, and Implications

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Presentation Transcript

  1. Key Issue 2 Where has the world’s population increased?

  2. Population Change • Geographers measure population change in a country or the world as a whole through three measures: • Crude Birth Rate • Crude Death Rate • Natural Increase Rate (NIR or NRI) • WHY ARE THESE IMPORTANT? • What do they tell us about the world? • Increase in population • Predict how quickly • Population trends

  3. Crude Birth/Death Rate • Crude means the world as a whole • CBR Definition: • Total # of live births in a year for every 1,000 people • Example: • CBR of 20 = • 20 births per 1,000 in a 1 year period • CDR Definition: • Total # of deaths in a year for every 1,000 people

  4. Natural Increase • NIR definition: • % by which a population grows each year • Formula: • CBR- CDR = NIR • 20 – 5 = 15 • =1.5% NIR • Natural increase means migration is excluded • World NIR • Early 21st century = 1.2% • All time peak in 1963 with 2.2% • 80 million people added annually • Even though NIR is slowing, population base is large

  5. Doubling Time • Rate of NIR effects doubling time • Definition: • # of years needed to double a population • Example • NIR of 1.2 = 54 years to double • If world NIR remains steady through 21st century world population will be 24 billion by 2100 • More than 95% of NIR is clustered in LDCs • Exceeds 2.0 in sub-saharan Africa and Middle East

  6. Population Explosion • The population continues to “explode” as the doubling time decreases. • Example: • 8 A.D. – 250 million • 1650 A.D.- 500 million • 1820 A.D.- 1 billion • 1930 A.D.- 2 billion • 1975 A.D.- 4 billion

  7. Fertility • Total Fertility Rate • Measures the # of births in society • Average # of children a woman will have during childbearing years (15-49 years) • CBR provides picture of society for given year • TFR attempts to predict future behavior of individual women • World TFR = 2.6 • Sub-saharan Africa =6 • Western Europe= .09

  8. Mortality • Two useful measures • CDR • Infant mortality rate • Definition: • # of deaths of infants under 1 year of age per year • IMR rates highest in poorer countries • Sub-Saharan Africa • 100 means 10% of all babies • Often reflect’s countries healthcare system • U.S. special example • high MRI for a MDC • Why? • Minorities, poor population access to healthcare

  9. Death Rate • Death rate is not a good statistic to use in determining quality of life. • Why? • Not all countries are at same stage…. • Example: US is wealthy MDC but may have more deaths because of an older population than Ethiopia.

  10. Life Expectancy • Definition: • Average # of years a newborn infant can expect to live at current mortality levels • Like all mortality/fertility rates higher in core/MDC nations • Western Europe = 80 years • Sub-Saharan Africa= 50 years • All become repetitious because all follow similar patterns

  11. Population Growth Curves • S Curve – historical growth • J Curve – exponential growth (fixed percentage)

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