Dr. Cho’s Website
Course Materials

Population growth vs. food supply growth

Dr. Huidae Cho
Institute for Environmental and Spatial Analysis...University of North Georgia

1   Population growth

Current world population

  • The world population in 2018 was 7.6 billion.
  • The population growth rate is approximately 1.09% or 0.0109.
  • $\mathrm{Pop}(y_c+1)=\mathrm{Pop}(y_c)\times(1+r_\text{pop})$
    • where $y_c$ is the current year and $r_\text{pop}$ is the growth rate.
  • The population grows exponentially.
  • So... the population in a future year $y_f$ can be estimated using \[\mathrm{Pop}(y_f)=\mathrm{Pop}(y_c)\times(1+r_\text{pop})^{y_f-y_c}\]

1.1   Population question

Estimate the world population in 2050.

2   Food supply growth

Thomas Malthus (an 18th century English scholar) observed:

  • The growth of human population is fundamentally different from that of food supply.
  • The food supply grows arithmetically (linearly).
  • $\mathrm{Food}(y_c+1)=\mathrm{Food}(y_c)+\mathrm{Food}(y_c)\times r_\text{food}$
    • where $r_\text{food}$ is the growth rate of food supply.
  • Generalizing this equation yields \[\mathrm{Food}(y_f)=\mathrm{Food}(y_c)\left[1+r_\text{food}\times(y_f-y_c)\right]\]

2.1   Food supply question

  • Let’s assume that $\mathrm{Food}(2018)$ can feed 110% of the 2018 world population and the growth rate of food supply is 1%.
    • Estimate the food supply in 2050 in the amount equivalent to population.
    • In what year, is the world population most likely to outgrow the food supply?

3   Population vs. food supply

Try this Excel.