I. Why should you study demography?
A. Demography provides the context to understand the debate around many of the pressing human problems of our time, such as famine, immigration, and government programs for the poor and elderly
II. The Human Population: The Problems of Demography
A. A billion people are hungry, a different set of a billion people lives in slums (with overlap), and a billion are illiterate (2/3s of these are women)
B. 200-215 million women don’t have contraceptive access. Half of all pregnancies are unplanned
C. Demography studies populations of humans, non-humans (viruses, bacteria, plants, animals), and non-living objects (lightbulbs, taxicabs, buildings). It studies these things in the past, present, and future, using quantitative data and mathematical models
D. QUESTION: How does demography relate to other fields?
1. Demography is related to the economy, environment, and culture
III. The Human Population: The Past
A. Since the invention of agriculture 12-14,000 years ago, the human population has multiplied by 1,000 times. From .25 billion to almost 7 billion
B. What will be the impact of that many people on the planet? Humans have already caused the extinction of many species.
C. 6/7s of human population growth since the birth of man has happened in the last 200 years
D. QUESTION: How did the human population reach a billion by 1800 (faster than exponential growth)?
1. Foodstuffs from the new world, potatoes and corn, fed the old world, and people left the crowding old world to go to the new world, which had seemingly unlimited resources. This was known as the Colombian Exchange
2. The Industrial Revolution began in 1800, and the population doubled to 2 billion by 1930. Doubling time: 1600 years to 200 years (1800: 1 billion), 200 years to 130 years (1930: 2 billion), 130 years to 44 years (1974: 4 billion)
E. QUESTION: What is this information concealing?
1. From 1950 to now: annual population growth rate reached a peak of 2.1% a year between 1965 and 1970. Since then it has fallen by half, to 1.1%. (There’s a sharp dip before 1965, because the Chinese Great Leap Forward killed 30 million people)
2. The world population is still growing, but at a slower rate. This is the swiftest voluntary change in reproduction in history. 1950: Average children per woman was close to 5. Today it’s 2.5. But not everywhere. Sub-Saharan Africa: 1950: 6.6 to 5.1 today
F. QUESTION: What does this change in reproductive behavior mean?
1. Replacement level fertility: When the population replaces itself 1:1 from one generation to the next. It’s about 2.1 children per woman
2. 1950: nearly 100% of women had above replacement level fertility. By 1975: 25% of woman were below replacement level. 2003: 50% of women were at replacement level or less for the first time in human history
3. Yet the average birthrate per woman is 2.5, not 2.1. Women who have above replacement level have a lot above. Thus overpopulation is still a problem
4. But the birthrate is still improving. It can improve faster with political, scientific, and civic intervention
A. Population pyramids: a basic tool of demography. Example shows that poor countries have a huge swell of school and military age people over the population of older people. For rich countries it’s much more even all the way up. Potential military forces in poor countries will vastly exceed rich countries in the future
B. Demographic growth is happening in countries least able to afford it. Rich countries have an average income of $32,000. For poor countries it’s $5,000. 3.5 billion people live on $2 a day or less
C. Population grows in poor countries despite the poverty. Their reproduction rates more than compensate for their high death rates
D. The rich world benefits from development of poor world. Richer people can buy more western products with better economies. Public health: diseases and outbreaks cross borders. Better health in poor countries improves health in rich countries
1. How much of the future is relevant to you? An 18 year old in 2011 has a 91% of surviving to 2050. We’re going to concentrate on now until then
2. The world’s population will get bigger, grow more slowly, have a dramatically increased fraction of older people, and will be more urban. Less certain: The nature of migration, household structures, and families
1. In 2050 using a constant fertility assumption: 11 billion people. Medium projection of the UN population division if growth rates continue declining at current rates: 9.1 billion. What we do between now and 2050 will have huge impact on an enormous range of human problems
2. Population growth could end by 2100 if we: educate women, provide credit to women where they can’t get it, provide reproductive health care to women where they can’t get it, and raise the age of marriage
C. Slower Growth
1. By 2050: Median projection: world will grow by 31 million a year. (growing by 76 million people now) 32 million in poor countries, -1 million in rich countries. The population is already declining in over 50 countries in 2011. As conditions improve people make a greater investment in a smaller number of children
I. By 2050 there will be three times as many 60+ year olds as 0-4 year old. We’re already in the first time in history when the old have outnumbered the young
II. Aging affects energy demand. Older household spend more on utilities, services, and health care
III. People who are educated in youth have less disability when older. Disability rates have dropped 1.5% per year in the US for last 25 years. Investing in the young now saves money and resources by lowering disability rates
I. In 2000 the world is in two equal parts, half rural and half urban. 3 billion each. 2050: Rural 3 billion, urban doubled to 6 billion. All of the new 3 billion urban will be in poor countries. A city of 1 million people would have to be built every 5 days from now to 2050 to accommodate this
II. QUESTION: What does this massive shift toward urbanization mean?
III. If we don’t invest in cities, slum population will go from 1 to 4 billion. Infectious disease will be rampant, and there will be warfare in cities
IV. (Many things are positive about urbanization. Lower fertility rates (children are assets on a farm, liabilities in a city), greater access to contraception (anonymity), economic productivity (80% of wealth generated by 50% of population), cultural assets (schools, health care), energy efficiency (the denser the city, the less CO2 used per person – NYC has 1/3 of per capita CO2 emissions as national average)
V. City hazards: built along coastlines (continental plates are along coasts, prone to earthquakes and tsunamis), rising sea levels from global warming will put parts of cities under water, coastal storms common, concentration makes infectious disease a bigger threat, as well as water supply attacks, and military and terrorist attacks)
VI. Cities occupy 3% of land on earth. Arable land is 10-11% of earth. Many cities are in middle of best arable land, due to food surpluses. Do we double area to 6% and eat more arable land, or make cities twice as dense? Depends on zoning, real estate developers, economics, civic choices.
A. Bigger pie: We should use technology to increase production; fewer forks: we should use contraception to reduce population growth and consume less; better manners: we should eliminate inequalities in wealth, gender, justice, populations
B. Cohen: Must educate children, both boys and girls, well for 10-12 years, high-quality primary and secondary. No chance to educate children if they haven’t had adequate nutrition in utero and up to the age of 3. Must get good food to pregnant women, lactating women, children up to age of three. Too late for many children by the time they get to school
C. A billion hungry people. We are dependent on other species for food for people, feed for animals, fuel for transportation (wood, biofuel, biomass, dung), fiber (trees supply paper products, wood), fascination (people love to see animals), pharmaceuticals (most drugs are based on natural compounds), transport (carry people), traction (pulling carts, ploughs), symbiosis (bacterial cultures in guts), disease (bacterial, fungal, and viral infections)
D. 925 million undernourished people, higher than the number has been in 40 years of measurement, 98% live in poor countries. 17.4 (1 in 7) million households in the US lacked the resources to provide enough food for all members. Highest food insecurity since measurement started in 1995
E. QUESTION: What’s the problem?
1. Less than half of grain is used to feed people. 1/6 goes to biofuel, 2/6 to feed livestock. We could feed 11 billion, but only feed 5.5 billion
2. Hunger is economically invisible. The very poor can’t enter markets to demand food supply increase. Their hunger doesn’t affect our costs
3. Cohen’s solutions: eliminate unintended pregnancy and educate all children, open credits and markets to small farmers (majority women), eliminate perverse subsidies for agriculture in rich countries (raise income of poor), use best farmland for farm and use chemicals responsibly; culture: promote healthy diets, adequate nutrition, fund more research for increased agricultural productivity for crops that feed people in poor countries
VII. Demography Offers Integrated Solutions
A. The population interacts with economics, environment, and culture. Immunize yourself against overly simply explanations. Can’t just control the population, let the market work, adjust policy, or focus on saving the environment. Sustainability directly affects the rural poor
B. Demography provides tools and analytical perspectives to understand better the world around you, gives you equipment to solve problems mentally, means to intervene more wisely and effectively in the real world