Chapter 5 - Future Population Trend

Question 1

Forecasting population

Answer 1

• In 1980, UN forecast population in 2015 of 7.41 billion, it was actually 7.38 billion
  -currently entering a period of slowing population: 0.2%/ year 2020-2100
• age specific survivorship function describes probability that. Person of a given age will not die over next year

Question 2

Forecasting mortality

Answer 2

• forecasting mortality likely to have much less effect but reductions in life expectancy will reduce NRR
• old age mortality is difficult to predict and quantitatively less important

Question 3

Forecasting fertility

Answer 3

• often made relative to replacement fertility, the level consistent with a constant population size in long run
  -TFR consistent with 0 population growth is 2.1 kids/women
• TFR predicted to rise from 1.64 to 1.75 for developed group

Question 5

AIDS in Africa

Answer 5

-2018 estimated 37.9 million people infected with HIV and 1.7 million new infections
-90% of people infected with HIV live in developing countries countries -SSA is 2/3 of world cases -epidemic destroying scarce human capital leading to decrease in population growth

Question 6

Is fertility likely to stay low in rich countries?

Answer 6

-maybe not
- failed to predict WWII baby boom

Question 7

Tempo effect

Answer 7

Rise in average age of childbirth affects TFR
- generalise: delay of x% of a year in childbearing will reduce TFR by x% of original level

Question 8

NRR

Answer 8

Each girl born produces 1 daughter -> eventually population growth rate of 0

Question 9

Demographic momentum

Answer 9

• measure % pop < 15 years
• even if all couples have children at replacement rate demographic momentum will carry overall side of population to 9.9 billion by 2065

Question 10

Great spike in world population growth

Answer 10

• WW Rostov calls this ‘the great spike’
• Right half more speculative