Population Growth

Our growing population The world’s population is more than three times larger than it was in the mid-twentieth century. The global human population reached 8.0 billion in mid-November 2022 from an estimated 2.5 billion people in 1950, adding 1 billion people since 2010 and 2 billion since 1998.

Population has experienced Exponential Growth

Linear increase = adding a percentage of people each year relative to starting year value

• Result: adding same amount each year and seeing consistent growth.

  Exponential increase = adding a percentage of people each year relative to the previous year.

  • Result: adding more people each year than the last year and seeing exponential growth

Growth rate increased dramatically between 1700 and 1968, but has slowed down globally in the last 50 years.

• Peak growth rate 2.1% in 1968
• Current growth rate ~1%

Doubling Time

• Doubling time (D) - Length of time it will take a population to double
• Calculated from the growth rate (G in % / yr)

$$D=\frac{70}{G}$$

• Average growth rate worldwide is 1% per year
• How many years until the world population doubles?
  • 70 years

Despite growth rates and doubling times decreasing, the population will continue to grow!

~10 billion by 2050 ~11 billion by 2100

Projections based on expected fertility rates mostly.

Population growth

• Population has experienced exponential growth
• Growth rates and doubling times have become shorter
• Possibly 10 billion people by 2050
• What factors contribute to population growth?
  • Life expectancy has increased (i.e., medicine improved)
  • Birth rates have greatly exceeded mortality rates
  • People are more mobile and can live anywhere
• But growth is uneven! Globally it has slowed but some regions are still rapidly growing…

Growth by Region

• All regions were growing until recently
• Over the next 80 years, European and Latin American populations will fall
• Asia will rise for awhile but then begin to fall
• Africa will continue growing
• North America here shows a continued rise but other projections have it falling

Population Growth by Region

First activity: Population Growth by Country $\to$ you will investigate population growth statistics of a country of interest to you and discuss the potential impacts of that growth on the economy, environment, and health.

Impacts of Rising Human Population

What problems would you expect with rising populations?

• Food supply ⇒ Renewable

• Water supply ⇒ Somewhat renewable

• Minerals

• Fuel

• Land

• Some believe we are already exceeding earth’s carrying capacity

  • ’Sustain basic, healthy, moderately comfortable standard of living’

Resources are unevenly distributed

• Resources distribution does not match population distribution
• Increased demand by third world countries to become first world

Expect problems with air, water, and land quality

Declining fertility rates ⇒ declining populations Expect…

• Rising taxes because of burden of ageing and retiring population
• Lack of innovation with limited workforce
• Stagnating standard of living