Population and environment – what's the connection?

Activity 1

Demographic data calculations

In the table of data on the Solomon Islands population in 1991, you will see it had a birth rate of 40 per 1000 people and a death rate of 5 per 1000. Use information in the table to answer the following questions.

  • Calculate the rate of increase of the population (as a percentage per year).
  • Using this figure, find out the predicted doubling time for the population. A mathematical formula exists for this but, put simply, you just divide the rate of increase into 70 for an approximate answer in years.
  • Draw a graph showing the increase in population from 1991 to the year by which it should have doubled. Read off from this your projection for the islands’ population for the year 2000.
  • If you were a demographer advising the country’s government to help it prepare for the future, what would you say in your report? (Refer to the information in the table.)
Solomon Islands population data (1991)
Population (in millions) 0.3
Birth rate (per 1000) 40.0
Death rate (per 1000) 5.0
Total fertility rate (average number of births per woman) 6.2
Population under 15 (%) 47.0
Population over 65 (%) 3.0
Urban population (%) 9.0

Teachers notes

  • Rate of increase: 3.5%
  • Approximate doubling time: 20 years
  • According to these figures, the islands’ population in 2000 should be approximately 0.4 million (The population will have doubled by 2011.)
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Posted April 2005.