POPULATION Changes Cycles Factors that Influence Population Distribution

POPULATION Changes & Cycles

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water)

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water) • Climate (hot/cold; wet/dry)

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water) • Climate (hot/cold; wet/dry) • Economic Development

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water) • Climate (hot/cold; wet/dry) • Economic Development • Government Policy (immigration policies)

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water) • Climate (hot/cold; wet/dry) • Economic Development • Government Policy (immigration policies) • Rural/Urban Settlement

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water) • Climate (hot/cold; wet/dry) • Economic Development • Government Policy (immigration policies) • Rural/Urban Settlement • Capital Resources (transportation, technology)

Factors that Influence Population Distribution • Natural Resources (oil, arable land, water) • Climate (hot/cold; wet/dry) • Economic Development • Government Policy (immigration policies) • Rural/Urban Settlement • Capital Resources (transportation, technology) • Conflicts (refugees)

Factors that Influence Population Growth Rates • Modern Medicine and Hygiene

Factors that Influence Population Growth Rates • Modern Medicine and Hygiene • Education

Factors that Influence Population Growth Rates • Modern Medicine and Hygiene • Education • Industrialization and Urbanization

Factors that Influence Population Growth Rates • Modern Medicine and Hygiene • Education • Industrialization and Urbanization • Economic Development

Factors that Influence Population Growth Rates • Modern Medicine and Hygiene • Education • Industrialization and Urbanization • Economic Development • Government Policy

Factors that Influence Population Growth Rates • Modern Medicine and Hygiene • Education • Industrialization and Urbanization • Economic Development • Government Policy • Role of Women in Society

These factors change over time …so does the population!

The Demographic Transition

The Demographic Transition

The Demographic Transition • • STAGE 1: Low Growth Most of humanity CBR & CDR varied year to year Both were high but comparable thus the NIR was essentially 0 • Hunters & Gatherers • Food was good – population grew • Food declined – population declined • No modern country remains in Stage 1

The Demographic Transition • STAGE 1: Low Growth • 8000 BC – • Agricultural Revolution –humans begin to domesticate plants and animals and no longer relied entirely on hunting and gathering • Despite this advancement – world population remained in stage 1 b/c population was unstable • War(s) • Disease(s) • Unpredictable harvests

The Demographic Transition • STAGE 2: High Growth • After 1750 AD the world’s population began to grow 10 times faster. • Several countries moved into Stage 2 • The CDR plummets while the CBR remains as high as in stage 1 • Thus the NIR is very high and population growth is rapid

The Demographic Transition • STAGE 2: High Growth • 1750 AD - Industrial Revolution –it caused major improvements in industrial technologies that transformed the process of manufacturing goods and delivering them to the markets. • New machines increased food production & allowed people to work in factories • Wealth improved sanitation & personal hygiene • Sewer systems are installed • HEALTHY PEOPLE LIVE LONGER!

The Demographic Transition • STAGE 2: High Growth • Europe & N. America entered Stage 2 around 1800 • Stage 2 didn’t diffuse to Africa, Asia, and Latin America until the 1950 s. • This push was caused by the Medical Revolution. • New medical technologies – invented in Europe & N. America eliminated many of the traditional causes of death and enabled more people to live longer lives.

The Demographic Transition • STAGE 3: Moderate Growth • CBR begins to drop suddenly • CDR continues to decline but not as sharply as the CBR • The population continues to grow but the NIR is much smaller than in Stage 2 as the gap between the CBR & CDR narrows • A society enters stage 3 when people CHOOSE to have fewer children.

The Demographic Transition • STAGE 3: Moderate Growth • Decline in mortality – especially infant mortality rates • Economics – people live in cities rather than rural areas • Rural – children can work – many kids are an asset • Urban – children can’t work – smaller homes • Europe & N. America entered this stage in the early 1900 s • Most in Asia & Latin America have moved to Stage 3 in recent years • Most African nations remain in Stage 2

The Demographic Transition • STAGE 4: Low Growth • A country reaches this stage when the CBR declines to the point where it is equal to the CDR and the NIR approaches 0 – zero population growth (ZPG) • Total fertility rate of 2. 1 produces ZPG (not counting immigration) • Most European Countries are in Stage 4 – approaching stage 5 • USA – TFR has been below ZPG since 2000 (but lots of immigrants)

The Demographic Transition • STAGE 5: Negative Growth (New Idea!!!) • The original Demographic Transition model has just four stages, however, some theorists consider that a fifth stage is needed to represent countries that have undergone the economic transition from manufacturing based industries into service and information based industries called deindustrialization. • Germany, Italy, Spain, Portugal, Greece, and most notably Japan, whose populations are now reproducing well below their replacement levels, are not producing enough children to replace their parents' generation. • China is in a similar situation (b/c of 1 child policy) but its population continues to grow because of how large it already is.

The Demographic Transition Fig. 2 -13: The demographic transition consists of four stages, which move from high birth and death rates, to declines first in birth rates then in death rates, and finally to a stage of low birth and death rates. Population growth is most rapid in the second stage.

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.

Rapid Growth in Cape Verde Fig. 2 -17: 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.

Moderate Growth in Chile Fig. 2 -18: Chile entered stage 2 of the demographic transition in the 1930 s, and it entered stage 3 in the 1960 s.

Low Growth in Denmark Fig. 2 -19: 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.

Let’s Review • No countries are currently in Stage 1 • The jump from Stage 1 to 2 was a result of innovations that resulted from the Industrial Revolution and then diffused…causing death rates to drop. • The shift from Stage 2 to 3 occurs over time as society changes in response to innovations (greater % urban, smaller families are more practical when life becomes more expensive)…birth rates begin to drop. • The jump from Stage 3 to 4 is a result of rapid social changes creating a decreased desire for child bearing and therefore a dramatic drop in birth rates…. . ZPG!

Thomas Malthus (1766 -1834) • English economist • One of the first to argue that the world’s rate of population increase was far outrunning the development of food supplies. • “An Essay on the Principle of Population” 1798 – Argued that population increased geometrically, whereas food supply increased arithmetically • • • Today: 1 Person, 1 unit of food 25 years from now: 2 persons, 2 units of food 50 years from now: 4 persons, 3 units of food 75 years from now: 8 persons, 4 units of food 100 years from now: 16 persons, 5 units of food

Neo-Malthusians vs. Critics • 2 main arguments to support Malthus’s Theory • At the time only a few relatively wealthy countries had entered stage 2 • Many LDCs have expanded their food production but have more poor people than ever before • World population growth is outstripping a wide variety of resources not just food production • Billions of people in search of food and energy • Wars and Civil violence will increase b/c of the scarcity of food and resources (fuel, farmland, clean air) • Urealistically pessimistic b/c they are based on a belief that the world’s supply of resources is fixed rather than expanding • A large population could actually stimulate economic growth and thus generate more ideas for improving technological advancement • Marxist criticism – Poverty, hunger, and other social welfare problems are associated with lack of economic development are a result of unjust social & economic institutions, not population growth • World posesses sufficient resources to eliminate problems if only these resources were equally shared. – capitalism is the problem

Malthus Theory and Reality • On a global scale, conditions during the past half-century have not supported Malthus’s theory. • Even though Human population has grown at its most rapid rate – world food production has consistently grown at a faster rate than the natural increase since 1950 (green revolution) • Better growing techniques, higher-yielding seeds, & cultivation of more land – expansion in food supply • Malthus also over predicted the world population growth – his estimate was that by 2000 we would be at 10 billion rather than 6 billion. • Rapidly declining CBR during the 90 s • Economic development • Distribution of contraceptives

World Health Threats • Epidemiology – branch of medical science that is concerned with the incidence, distribution, and control of diseases that affect large numbers of people. • Medical researches have identified an epidemiologic transition that focuses on distinctive causes of death in each stage of the demographic transition.

Epidemiologic Transition – Stage 1 • Stage 1 – pestilence and famine • Infectious and parasitic diseases were principal causes of human deaths, along with accidents and attacks by animals and other humans • The Black Plague – bubonic plague – probably transmitted to humans by fleas from migrating infected rats. • Originated in present-day Kyrgyzstan - 1347 • Spread from coastal cities to inland towns – rural areas • 1347 -1350 – 25 million Europeans died (1/2 of the population) • 1380 – China – 13 million died

Epidemiologic Transition – Stage 2 • Stage 2 – Receding pandemics • Pandemic – is a disease that occurs over a wide geographic area and affects a very high proportion of the population • Improved sanitation, nutrition, and medicine during the Industrial Revolution reduced the spread of these diseases. • Outbreaks of Cholera sprang up in the crowded cities – mainly affected the poor – some thought that it was a punishment for sin (Poverty=sin) • Real cause were contaminated water sources • New water & sewer systems eradicated cholera by the late 1800 s • Reappeared in the rapidly growing cities in developing countries as they moved into stage 2 of the demographic transition

Epidemiologic Transition – Stages 3 & 4 • Stage 3 – Degenerative and humancreated diseases • Decrease in deaths from infectious diseases and an increase in chronic disorders associated with aging • Cardiovascular diseases (heart attacks) and various forms of Cancer • Stage 4 – Delayed degenerative diseases • Cardiovascular and Cancer remains but is treatable • Cancer can be slowed • Operations • Improved health and behavior

Epidemiologic Transition – Stage 5 • Stage 5 – Reemergence of infectious and parasitic diseases • Some diseases thought to have been eradicated or controlled have returned, and new ones have emerged. • Evolution – Infectious disease microbes evolve and change in response to the environment • Malaria – spraying DDT to kill the mosquitos – now there are DDT-resistant mosquitos • Poverty – Poor living conditions and most people cannot afford the treatment • Tuberculosis (TB) (Consumption) – airborne disease spreads principally though coughing and sneezing. • Improved travel – Cars, Airplanes – as people travel they carry diseases with them and expose others to the disease • SARS – severe acute respiratory syndrome – China 2002 • Small. Pox – Most Americans are no longer immunized against it because there hasn’t been an outbreak here since 1947 and worldwide in 1977 in Somalia - Terrorists • AIDS – 1980 (200, 000) 1990 (8 million) 2001 (40 million)