Historical Human Population Curve

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1 A glance at our Global Village If we could shrink the Earth s population to a village of precisely 100 people with all existing human ratios remaining the same, it would look like this: 1. There would be 57 Asians, 21 Europeans, 14 from the Western Hemisphere (North and South) and 8 Africans would be female; 49 would be male; 90 % are heterosexual would be non-christian; 30 Christian would be non-white; 30 white 5. 50% of the entire world s wealth would be in the hands of only 6 people, and all 6 would be citizens of the United States would live in substandard housing would be unable to read would suffer from malnutrition would be near death, 1 would be near birth. 10. Only 1 would have a college education, and one would own a computer. Historical Human Population Curve Human Population Doubling Time Doubling Time Doubling Time of a population (years) : 70 / Population Growth Rate (%) ( 70 / 1.1% = 64 years ) 1

2 Chapter 4 The Human Population Challenge Population Trends - Projected to have 7 billion people by the year Most of the increase will be in Africa, Asia, and Latin America. Already have 82% of the worlds population, the lowest GNP, and the lowest standard of living Growth in LDCs vs MDCs 2

3 Population Growth Issues Contributes to all world problems famine, political unrest, environmental degradation from poor agriculture, water pollution, air pollution, loss of bio-diversity, destruction of natural resources. Ultimate Size Limitation Carrying Capacity If the world continues to grow at current rate, population will reach 12 billion by Human population subject to same biological constraints as other species. With certainty, human population will ultimately reach a carrying capacity and stabilize. Disagreement about exact size and primary limiting factors. Human Population Growth Interactions Affecting Carrying Capacity Available Raw Materials Available Energy Waste Disposal p Interaction With Other Organisms 3

4 Causes of Growth Birth rates and death rates Growth rate should be controllable - Is reducing the birth rate better than increasing the death rate? Doesn t work so easily - look at the demographics most growth in least developed nations Factors to consider Number of women having children Number of children born to each woman If total fertility rate (number of children born in a woman s life) is 2.1, the human population will stabilize and reach zero population growth Factors to consider Stabilization will not happen immediately. Death rate will decrease as people live longer Initially, many young families will start having children May take from 20 to 100 years to stabilize. Age Structure Profiles 4

5 Demands are different among populations Developed countries demands are much higher than developing Developed countries demands are spread around the world Developing countries export resources to developed countries Impacts = population size / area X degree of technological development Social Factors Influence Human Population Humans are social animals who have freedom of choice. People make decisions based on history, social situations, ethical and religious beliefs, and personal desires. Biggest obstacle to controlling human population are province of philosophers, theologians, politicians, and sociologists. Social Reasons Desired family size is determined by religion, tradition, social, and economic factors. Male-dominated cultures places high values on women having and raising children (usually when quite young) and little value on educating women. Social Reasons Birth control only helps if people want to limit the size of their family Why want a large family?? Infant mortality may be high Have children to support you in your old age (form of social security). More family members to earn income (especially in farming communities). Political Factors Some countries have population goals or laws and may offer incentives (tax breaks, free birth control). China has used more political control techniques than any other country and their population is still not stable. Demographic Transition High standard of living occurs in areas where population growth is small. Likewise, low standard of living occurs in areas where population pp growth is high. concept is that countries naturally go through stages (based on European and North American experience) 5

6 Demographic Transition Stable population with high birth and death rates Improved conditions bring about rapid growth as death rate falls As development occurs economic and social factors cause a decrease in birth rates Eventually, birth and death rates become equal Demographic Transition High standard of living occurs in areas where population growth is small. Likewise, low standard of living occurs in areas where population pp growth is high. Concept is that countries naturally go through stages (based on European and North American experience) Can all countries go through Demographic Transition?? Those that already have did so experienced it when energy, natural resources, and land were abundant because the world population was low - safety valve Technological development is unlikely to keep up with the large population growth currently occurring 6

7 Population Growth Issues Contributes to all world problems famine, political unrest, environmental degradation from poor agriculture, water pollution, air pollution, loss of bio-diversity, destruction of natural resources. U.S. Population About 306 million today. low birth rate and growth rates (0.6 % from births, 0.5% from immigration) Baby boomer bulge in the population pyramid. By 2030, 20% of the population will be 65 years or older Population size will be about 383 million by 2050 Age distribution of U.S. pop Components of U.S. Pop Growth FYI Since the beginning of class we have added about 9600 people to the world population. (~2 people per second, 60 seconds per minute, 80 minutes per class) We add the population of Denton (about 100, or so) about twice per day, every day. ~12 million people die each year from starvation equivalent to 65 jumbo jets carrying 500 passengers crashing each day 7

8 World Hunger Chapter 5 12 million people die each year from starvation ½ are children Equivalent to 65 jumbo jets with 500 passengers crashing each day 33,000/day One in five people (~1.2 billion) consume less food than needed to stay health 10% of households in U.S. are hungry, on edge of hunger. Hunger affects 1 in 5 American children Food Issues Under nutrition One in seven people world wide regularly consume less food than they need to stay healthy ~ 1.2 billion Africa, Asia, Latin America In U.S. 10% of households go hungry. - 1 in 5 American children are affected by hunger Malnutrition Malnutrition results from a lack of protein and/or calories in diet Results in diseases like marasmus and kwashiokor that affect young children Result in brain damage and often death 8

9 Three challenges How to end current suffering from food shortages How to meet demands from future population growth How to do these things without destroying our natural capital sustainable agriculture?????????????????????????????????????? Six Historical Strategies For Addressing World Hunger Sustainabily Urban Sprawl 1. Protecting existing soils from erosion and conversion 24 billion metric tons of top soil lost per year In a decade this = equivalent to ½ of all topsoil on all the farms in U.S In the last 25 years 370 million acres of farm land was lost world wide by conversion to non- farm use = all the farm land in U.S Texas leads the nation in loss of productive farmlands and rangelands to development 9

10 Stategies Increase productivity of existing farmland and restore depleted soils By increasing irrigation efficiency By increasing crop yield Green Revolution Genetic Engineering GM crops North America versus Europe Are they safe? Precautionary Principle Increase use of Fertilizers How? Strategies Reduce Pest Damage 40% of food grown in world is destroyed by pest and diseases. How? Pesticides?, biological control, Integrated pest management 10

11 Strategies Improving food storage and distribution Developing new food sources Improvement in livestock Algae, Native Grazers-African Wildlife Expanding the land under cultivation Bring marginal lands into production? Convert tropical forest, arid land and wetlands into farmlands Is this wise? Sustainable Strategies to Eliminate Hunger Raise standard of living in LDC How Develop sustainable businesses Micro-business loans Stop conflicts and wars How? Address Problems in LDCs caused by Free Trade Free trade has made it difficult for poor farmers in LDCs to compete with the farm industry in MDCs Experts advise for local production and local consumption sustainable agriculture- self sufficiency Impacts on the Environment Will have to shift some biomass to food for human population It is easy to mismanage agriculture and create damage (e.g. dust bowl) China Long term impacts of providing food by decreasing biodiversity are unknown Can feed more people on plants than animals 10 times more 11

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