Human Population

1. Human Population

2. Some alarming statistics

3. Late 1600’s – ½ billion people • 1830 – 1 billion • 1930 – 2 billion • Since 1975 – world’s population has added 1 billion ever 12 years • Greatest growth occurring in developing countries • By 2050 – 10.5 billion

4. Causes of “explosion” • Technology • Improved sanitation • Better medical care • Increased agricultural output • These and others led to a decrease in death rates, primarily infant death rates

5. Environmental Impacts • Cornucopian view – resource depletion is not a problem if new resources can be found to replace • Not all resources are replaceable • Even if it could, could we maintain the quality of life we desire?

6. Environmental Impacts • IPAT Model represents how human impact (I) results from interaction among three factors: • Three factors: population, affluence, technology I = P x A x T • Impact can be boiled down to pollution and/or resource depletion

7. demography

8. Demography • The science of human population • Principles of population ecology apply to humans • Humans have a carrying capacity set by environmental limitations • Estimates: 1-2 billion living prosperously to 33 billion living in poverty

9. Demography • Uneven distribution means certain areas bear more burden • Areas of low population density are often vulnerable to impact (sensitive environment that cannot support many people) • Age structure diagrams show relative sizes of each age group in a population; used to predict future population dynamics

12. Demography • Population growth depends on rates of birth, death, immigration, and emigration = (birth + immigration) – (death + emigration) • Immigration and emigration play a large role today • Since 1970 growth rates in many countries have been declining

13. Demography • Total Fertility Rate (TFR): average number of children born per female during her lifetime • Replacement fertility is the TFR that keeps the size of a population stable; for humans it is 2.1(in developed countries, slightly higher in undeveloped countries) • A lower infant mortality rate has reduced people’s tendency to conceive many children to ensure some survive • Natural rate of population change is change due to birth and death rates alone

14. Demography • Many nations experience a change called demographic transition • This is a model of economic and cultural change that explains the trends in declining birth and death rates as nations industrialize • Four stages: pre-industrial, transitional, industrial, post-industrial

17. Demography • Despite technological advances, earth does not have enough resources for existing and future generations to maintain standard of living equal to developed countries • Is the demographic transition universal?

18. Population and society

19. Civil Rights for Women • In societies in which women are freer to make reproductive decisions, fertility rates have declined • Children are better cared for, healthier, and better educated

20. Population Policies • Thailand – relied on education-based approach to family planning • India – 1st country to implement population control measures. Strident policies in the 1970’s. Now focus on education, family planning • Brazil, Mexico, Iran, Cuba et al, have instituted programs with reduction targets, incentives, education, contraception and reproductive health care

21. Population Policies • UN in 1994 – Cairo conference on population & development. 179 nations endorsed all gov’ts to offer repro health care w/in 20 years • US has often declined to fund family-planning efforts by the UN

22. Other Factors & Influences • Poverty is strongly correlated with pop growth • Consumption from affluence creates huge impact on environment • 1999 – the richest 20% of people used 86% of world’s resources • HIV/AIDS leads to premature deaths, reducing life expectancy in African nations • AIDS is undermining ability of developing countries to make transition modern tech