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Demographic Changes
Demographic Transition ModelTransitions In World Population
Calculating Population Change
Four variables for population equation
– Births + immigration = increase– Deaths + emigration = decrease
• (CBR+I)-(CDR+E)= Total population• This equation better suited to study
population trends rather than specifics• In what ways might geographers use this
data?
Demographic Transition Model• Used to determine stages of a country’s
growth• Graphs population, time, birth and death rates
(doesn’t account for migration)• Used to correlate a country’s progress in
technology and society
Pop
Stages/Time
Stage 1: Low Growth (High Stationary)
• Overall Population is sparse• High birth-high death= stationary pop• Lack of major food surplus keeps
population low• Super long doubling time• ALL WORLD REGIONS UNTIL 17th C• Agricultural Revolution: domesticated
plants/animals make for better food sources and lead to transition
Population graph for the first four million years
Stage 2: High Growth (Early Expanding)
• CDR decreases rapidly (especially people under the age of 5)
• CBR remains steady• Results in natural increase• Industrial Revolution
– Technology produces and transfers goods– Industry and farming improve
• Sanitation improvements- examples?• Medical advancements- examples?• Bangladesh, Nigeria, Pakistan
Stage 3: Moderate Growth (Late Expanding)
• CBR drops• CDR drops but slower than stage 2 decrease• NIR is modest• CBR drops because of new technologies
– People have fewer kids– Medical advances mean less chance of children dying– Economic factors: less farming more urban
• How does this correlate?
– Women become better educated• How does this correlate?
– China, Brazil, Mexico, India
Entering Stage Three
Even though birth rate is falling, population momentum keeps the total population growing.
Stage 4: Low to No Growth (Low Stationary)
• CBR=CDR (little to no growth)• Most European nations in Stage 4
– U.S. moving in this direction
• Social Customs– Women working– Employed parents need to plan for day care– Entertainment and leisure activities– EXPLAIN!
US, Sweden, Japan, Britain
Stage 1 Stage 2 Stage 3 Stage 4
Low growth incr grwth decr grwth low/no
Birth Rate
Death Rate
Total Population
Problems with the Model?
• No "guidelines" for how long it takes a to get from Stage I to IV. Just describes it– Western Euro countries took centuries– Economic Tigers took decades.
• Nations that were populated by emigration did not go through early stage
• Birth rates have fallen below death rates in some areas, should there be a stage V?
PROPOSED FIFTH STAGE:
• Negative population growth• CBR drops to zero-CDR very low-population
is slowly dying out (Children of Men) • Not enough people in the work force to
support programs for the aged (dependency ratio very lopsided)
• Social programs overloaded-unrest & probable chaos
• Innovations stagnantPrezi