Human Population -- Doubling Time

Human Population Growth:  Doubling Time

Introduction:

            Birth and death rates determine the rate of population growth.  If the birth and death rates are similar, a population experiences little or no growth.  When the birth rate far exceeds the death rate, the population soars.  These rates are expressed as the number of births or deaths for every 1,000 people in a given year.  For instance, in 2007 the world’s birth rate was 21 per 1,000 and the death rate was 9 per 1,000.  Using the formulas below, one can determine the world’s annual growth rate and the number of years it will take the population to double if the growth rate remains constant.

World Population Growth Rate = (birth rate - death rate)/10 = (21 - 9)/10 = 1.2%

World Doubling Time (in years) = 70/(population growth rate) = 70/1.2 = 58.3 years

(NOTE:  70 is the approximate equivalent of 100 times the natural log of 2.)

Using the table below, determine the percentage of annual increase and the population doubling times for each country.

Population Growth Rate   =      (birth rate)  -  (death rate)

                                                                     10

Doubling time (in years)   =                    70_______

            Population Growth Rate