Demographic Changes Demographic Transition Model Transitions In World Population.

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