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Population Doubling Time. Population Doubling Time. Population Doubling Time. Definition: The amount of time for a given population to double, based on the annual growth rate .
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Population Doubling Time Population Doubling Time • Definition: The amount of time for a given population to double, based on the annual growth rate. • Ex.) Currently Canada’s population is Approx. 30 Million. If it grows at a constant rate of 5 Million a year it will take 6 years (30 / 5) for Canada’s population to double to 60 million. Therefore doubling time = 6 years!
Rule of 70 • To determine the doubling time, divide the growth rate as a percentage into 70. i.e., a growth rate of 3.5 represents a doubling time of 20 years.
Exponential Growth • Exponential growth occurs when some quantity regularly increases by a fixed percentage • In the case of a population doubling time, the population is regularly increasing by 100%.
Note: rates of growth change from year to year for populations • The doubling time is only that if the rate of growth remains the same.