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Key Issue 3: Why is Population Increasing at Different Rates in Different Countries? Demographic Transition Model www.prb.org/pdf04/transitionsinWorldPop.pdf (check out pg 8) The demographic transition consists of four stages, which move from high birth and death rates, to declines first in death rates then in birth rates, and finally to a stage of low birth and death rates. Population growth is most rapid in the second stage. The Demographic Transition The Demographic Transition – 1. Low growth – 2. High growth – 3. Moderate growth – 4. Low growth Population pyramids – Age distribution – Sex ratio Countries in different stages of demographic transition Demographic transition and world population growth Demographic Transition Model Stage one – Crude birth/death rate high – Fragile population Stage two – Lower death rates – Infant mortality rate – Natural increase high Stage three – Indicative of richer developed countries – Higher standards of living/education Stage Four – CBR and CDR are at equilibrium or almost = – ZPG= Zero Pop. Growth – Most Northern and Western Euro countries Rapid Growth in Cape Verde Cape Verde, which entered stage 2 of the demographic transition in about 1950, is experiencing rapid population growth. Its population history reflects the impacts of famines and outmigration. Moderate Growth in Chile Chile entered stage 2 of the demographic transition in the 1930s, and it entered stage 3 in the 1960s. Low Growth in Denmark Denmark has been in stage 4 of the demographic transition since the 1970s, with little population growth since then. Its population pyramid shows increasing numbers of elderly and few children. Stage One Pre-industrial CBR and CDR high and fluctuate according to natural events and disasters. Population is a constant and young pop. Stage Two Death rates drop… improvements in food supply, sanitation, etc. Birth rates do not drop… causes an imbalance so there is a large increase in population. Stage Three Birth rates fall – Access to contraception – Increase in wages – Urbanization – Move away from subsistence agriculture. – Education of women Population to level off growth begins Stage Four Low birth AND low death. Birth rates may drop below replacement levels (Japan and Italy) which may lead to negative population growth. Large group born during stage 2 ages… creates a burden on the smaller working population. Soooo…. A cycle in a way from 1 to 4 Difference= in Stage 1 CBR and CDR are high… in Stage 4 they are low. Difference= total population of a country is higher in Stage 4 than in Stage 1 Dependency Ratio A country wants a balance between young, working, and elderly populations… this is called the dependency ratio. Most of the population should be in the “working years.” Some countries have many births/children who are dependent, others have the older generations. “World Aging at Super Speed”: http://money.cnn.com/2014/08/21/news/economy/aging-countriesmoodys/index.html?sr=fb082214superaged3pVODtopPhoto The Demographic Transition in England Now Stage 4 Historically – Stage 1 – Low growth until 1750 – Stage 2 – High growth 1750-1880 – Stage 3 – Moderate growth 1880-early 1970’s – Stage 4 – Early 1970’spresent. Long time below the 2.1 Total Fertility Rate needed for replacement. Problems with the Demographic Transition Model • based on European experience, assumes all countries will progress to complete industrialization • many countries reducing growth rate dramatically without increase in wealth • on the other hand, some countries “stuck” in stage 2 or stage 3 • it is not an exact science!!!!!!!! (Possible Stage 5????) Remember… Demographic Transition is not only dependent on CBR and CDR but also on in and out migration!!!!