# Where has the world’s population increased?

## Presentation on theme: "Where has the world’s population increased?"— Presentation transcript:

Where has the world’s population increased?
Key Issue 2 Where has the world’s population increased?

Population Change Geographers measure population change in a country or the world as a whole through three measures: Crude Birth Rate Crude Death Rate Natural Increase Rate (NIR or NRI) WHY ARE THESE IMPORTANT? What do they tell us about the world? Increase in population Predict how quickly Population trends

Crude Birth/Death Rate
Crude means the world as a whole CBR Definition: Total # of live births in a year for every 1,000 people Example: CBR of 20 = 20 births per 1,000 in a 1 year period CDR Definition: Total # of deaths in a year for every 1,000 people

Natural Increase NIR definition:
% by which a population grows each year Formula: CBR- CDR = NIR 20 – 5 = 15 =1.5% NIR Natural increase means migration is excluded World NIR Early 21st century = 1.2% All time peak in 1963 with 2.2% 80 million people added annually Even though NIR is slowing, population base is large

Doubling Time Rate of NIR effects doubling time Definition:
# of years needed to double a population Example NIR of 1.2 = 54 years to double If world NIR remains steady through 21st century world population will be 24 billion by 2100 More than 95% of NIR is clustered in LDCs Exceeds 2.0 in sub-saharan Africa and Middle East

Population Explosion The population continues to “explode” as the doubling time decreases. Example: 8 A.D. – 250 million 1650 A.D million 1820 A.D.- 1 billion 1930 A.D.- 2 billion 1975 A.D.- 4 billion

Fertility Total Fertility Rate World TFR = 2.6
Measures the # of births in society Average # of children a woman will have during childbearing years (15-49 years) CBR provides picture of society for given year TFR attempts to predict future behavior of individual women World TFR = 2.6 Sub-saharan Africa =6 Western Europe= .09

Mortality IMR rates highest in poorer countries U.S. special example
Sub-Saharan Africa 100 means 10% of all babies Often reflect’s countries healthcare system U.S. special example high MRI for a MDC Why? Minorities, poor population access to healthcare Two useful measures CDR Infant mortality rate Definition: # of deaths of infants under 1 year of age per year

Death Rate Death rate is not a good statistic to use in determining quality of life. Why? Not all countries are at same stage…. Example: US is wealthy MDC but may have more deaths because of an older population than Ethiopia.

Life Expectancy Definition:
Average # of years a newborn infant can expect to live at current mortality levels Like all mortality/fertility rates higher in core/MDC nations Western Europe = 80 years Sub-Saharan Africa= 50 years All become repetitious because all follow similar patterns

Population Growth Curves
S Curve – historical growth J Curve – exponential growth (fixed percentage)