1 Ch8: Human Population Human popn is growing at a faster rate than anytime in history Most recent popn growth is slowing Human popn & consumption affect ecosytems Age structure is imp. to discussions about popn growth. I. Human popn growth A. Capacity to produce more people than resources can support B. China: one-child policy in 1970 1. growth has declined 2. absolute popn size 3. 1.3 billion people 4. unintended outcomes. C. The world adds ~ 2.5 humans each second 1. ~ 80,000,000 people are added per year 2. 6.8 billion people (2010). D. Popns continue to rise in most countries, E. Rate of growth is slowing, but F. Growth rates vary regionally r = birthrate – death rate G. Results from technology, sanitation, food H. Some people say growth is no problem: New resources Irreplaceable resources I. Quality of life suffers with unchecked growth Less food, J. Fears concerning declining human popns 1. Policymakers beliefs offer incentives for more children birthrates viewed as too low in birthrates viewed as too high in 2. Popn growth is correlated with poverty, not wealth What are some causes and effects of human population growth?(page 210) II. Ecological footprints A. IPAT model: I = P x A x T x S ENV 2100 Environmental Science, Dr. L. Kelly2 I = total impact P= popn size A = affluence T = technology S = sensitivity factor B. U.S. has largest ecological footprint: 1) per capita 2) total C. Global footprint is 2.5 times its size in 1960 III. Demography A. = study of popn statistics (births, deaths) B. All popn principles apply to humans; C. Humans raise environment’s carrying capacity through technology --- But how many humans can world sustain? Popn growth can’t continue forever D. Age structure 1. affects popn size & growth 2. how do younger age classes affect growth? 3. many popns are getting older: E. Sex ratios -- natural ratio for humans slightly favors males F. Whether popn grows, shrinks, or remains stable depends on: birthrates, death rates, & migration G Immigration & emigration Do falling popn growth rates necessarily mean fewer people? IV. Factors affecting fertility rates A. How does urbanization influence fertility rates? 1. children are schooled 2. elderly parents on social security B. Greater education for women C. Access to birth control, family planning programs, & better education affect rates Enpowering women vs. fertility rates (page 221) V. AIDS impacts African popns A. Nearly half of all HIV/AIDS cases occur in sub-Saharan Africa; B. Contraceptive use AIDS has severe effects, rivals Black Death and