Key issue #2
Where has the world's population increased?
Key Terms
Crude Birth Rate (CBR)- Crude birth rate is the nativity or childbirths per 1,000 people per year
Crude Death Rate (CDR)- the total number of deaths per year per 1000 people.
Natural Increase Rate (NIR) - is the percentage by which a population grows in a year. It is crude birth rate minus the crude death rate per 1,000 people.
Doubling time- is the period of time for a quantity to double or in this case a population to double.
The NIR for the World's population as a whole has been steadily decreasing since around 1962 when it hit its all time high of 2.2%. For the first decade of the 21st Century the population was growing by 1.2% percent each year meaning that the NIR was 1.2%, but this doesn't necessarily mean that the world's population growth has decline since 1962. In fact only during the 21st century did the world's population growth start declining. Because the world has so many more people than it did in 1962 (almost double) a decrease in NRI can still output an increase in population.
By changing the rate of natural increase you also change the rate of doubling time. This means that when our NIR was 1.2% it would have taken roughly 54 years to double or population if had stayed the same and if it continued till 2100 our population will nearly quadrupled to 24 billion. This means that if the NIR from 1962 of 2.2% had stayed steady till 2000 our population would have been bigger by nearly 500,000,000 people and if it had continued through the 21st century our population would be 50 billion people by 2100 that's 8-9 times our population today.
