- Slides: 19
Population increases at different rates Key Issue 3: Why is population increasing at different rates in different countries? ØThe demographic transition model ØPopulation pyramids ØCountries in different stages of demographic transition ØDemographic transition and world population growth
The Demographic Transition Modal – It is a model consisting of four stages that helps to explain the rising and falling of natural increase over time in a country. – Historically, no country has ever reverted back to a previous stage. • Thus, the model can be thought to have a beginning, middle, and an end.
Demographic Transition Model: Development & Population Intersect…
Demographic Transition Stage 1: Early Stationary Stage (No country is currently here) Ø Population growth: slow increase Ø Birth rates: high Ø Death rates: high Most of humanity’s several-hundred year occupancy of Earth was characterized by stage 1. Birth and death rates varied considerably from one year to the next and from one region to another, but over the long term they were roughly comparable, at very high levels. Between 8000 B. C. and A. D. 1750, Earth’s human population increased from 5 million to 800 million. The burst of population growth around 8000 B. C. was caused by the agriculture revolution. Despite the agriculture revolution, the human population remained in stage 1 of the demographic transition because food supplies were unpredictable.
Demographic Transition Stage II: Early Expanding Stage Ø Birth rates: high Ø Death rates: decreasing Ø Population growth: rapid and increasing After around A. D 1750 the world’s population suddenly began to grow 10 times faster than in the past. In stage II, the crude death rate plummets, while the crude birth rate remains the same as in stage I. Most African countries are still in a stage II. With the advent of the Industrial Revolution and the improvements in technology, population growth rate changed. Countries in Europe and North America entered stage II of the demographic transition about 1800, but stage II did not diffuse to most countries in Africa, Asia, and Latin America until the 1950’s. The late 20 th century push of countries into stage II was caused by the medical revolution.
Percent of Population under 15 About one-third of world population is under 15, but the percentage by country varies from over 40% in most of Africa and some Asian countries, to under 20% in much of Europe.
Rapid Growth in 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 out-migration.
Demographic Transition Stage III: Late Expanding Stage Ø Birth rates: decreasing Ø Death rates: leveling off Ø Population growth: rapid but slowing A country moves from a stage II to a stage III when the birth rate begins to drop sharply. European and North American countries moved from stage II to a stage III during the first half of the 20 th century. Most countries in Asia and Latin America have moved to a stage III in recent years. A society enters a stage III when people decide to have fewer children. Medical practices introduced in stage II improve the probability of infant survival, but many years pass before families react by conceiving fewer babies.
Demographic Transition Stage III continued…… Economic changes in stage III also induce families to have fewer offspring. Farmers often consider a large family to be an asset. In contrast, children living in cities are generally not economic assets. About 75% of the world’s population is stranded in stages II and III. Q&A: What does improve technology increase? resource availability standard of living health care ? ?
Moderate Growth in Chile entered stage 2 of the demographic transition in the 1930 s, and it entered stage 3 in the 1960 s.
Demographic Transition Stage IV: Late Stationary Stage Ø Birth rates: low Ø Death rates: low Ø Population growth: low A country reaches stage IV when the birth rate declines to the point where it equals the death rate. The condition is called ZPG. Most European countries have reached stage IV. The United States has moved slightly below ZPG since 2000. When families lived on farms, employment and child rearing were conducted at the same place, but in urban societies parents leave the home to work. Changes in lifestyles also encourage smaller families. Several Eastern European countries, most notably Russia, have negative natural increase rates, a legacy of Communist rule.
Low Growth in Denmark has been in stage 4 of the demographic transition since the 1970 s, with little population growth since then. Its population pyramid shows increasing numbers of elderly and few children.
Demographic Transition in England was one of the first countries to experience rapid population growth in the mid-eighteenth century, when it entered stage 2 of the demographic transition
Why Does Population Growth Vary among Regions? • Population Futures – Demographic Transition Possible Stage 5: Decline • Characterized by… – Very low CBR – Increasing CDR » More elderly people than young persons – Negative NIR – Over time, few young women in child-bearing years » Contributing to ever falling CBR • Several European countries already have negative NIR. – Russia is most notable hosting a negative NIR for 50 years.
Demographic Transition Ø Less developed countries : mortality revolution after World War II; changes did not result from economic development within the countries, but were a result of international aid. Ø The impact of Western technology moves a population from a stage I into a stage II. Industrialization and economic development moves populations into a stage IV
• Declining Birth Rates – Two Successful Strategies for Lowering Birth Rates 1. Improving Education and Health Care – Emphasizes improving local economic conditions so that increased wealth is allocated to education and health programs seeking to lower birth rates. 2. Contraception – More immediate results reaped than previous approach – Met with greater resistance, because it goes against cultural or religious beliefs of some. » Roman Catholics, fundamentalist Protestants, Muslims, and Hindus.
Population Video You’re going to love this! You may have to watch it twice! As you are watching do the following: Do you agree with what he is saying? (You can disagree, you just need to back up what you are thinking!) List 5 statistics/facts he discusses. Do the statistics tell the whole story? Why or why not? What will happen if the world continues on the path he is predicting? Is there a “solution” to what is happening? https: //www. youtube. com/watch? v=jbk. S RLYSojowww. youtube. com/watch? v=jbk. SRLYS ojo