Chapter Essay. Rapid Human Population Growth. Rapid Human Population Growth. The Lessons of Easter Island By Jared Diamond, Ph.D. Today s Objective:

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1 Chapter Essay Essay: The Lessons of Easter Island By Jared Diamond, Ph.D. Today s Objective: 26.4 How Is the Human Population Changing? The Human Population Continues to Grow Rapidly. Technological Advances Have Increased Earth s Carrying Capacity to Support People. The Demographic Transition Helps Stabilize Populations. A Quiz Question for You: Q: Which of the nations listed below has the lowest annual rate of increase (as a %)? A. New Zealand B. Australia C. China D. United States 1

2 In the last few centuries, the human population has grown at nearly an exponential rate. follows a J-shaped growth curve associated with exponential population growth. Population Doubling Times World Population of Humans: 6,629,952,311 Net Growth/year (2004) ,401,492 Growth/month ,450,124 Growth/day ,059 Growth/hour ,836 Growth/minute Growth/second ~2.5 Sources: 2

3 United States: 303,322,309 One birth every... 8 seconds One death every seconds One migrant (net) every seconds Net gain of one person every seconds Sources: Most species must "make due" with the resources in an area. Humans have manipulated the environment to increase the Earth s carrying capacity for humans. Global Is Unevenly Distributed Fertility in Europe Is Below Replacement Level The United States Populations Is Growing Rapidly Technological Advances Technical and cultural revolution Primitive humans tools and weapons increased hunting effectiveness. Fire, shelter, & clothing increased habitable area. Agricultural revolution (c. 8,000 B.C.) Domesticated plants/animals more food (stable). Industrial-medical revolution (mid-18 th Century) Allowed fewer people to produce more food and decreased the death rate from infectious diseases. 3

4 Demographic Transition In "developed" countries, the industrial-medical revolution resulted in an initial rise in population, which then stabilized. Caused by a decrease in death rates, followed later by a decrease in birth rates. This change in population size is called a demographic transition. Demographic Transition Declining birth rates associated with from: Increased access to contraceptives. Education. Demographic shift to cities. Women working outside the home. Replacement-level Fertility (RLF) In most developed nations. When adults have enough children to replace themselves. RLF is slightly higher than Even if countries drop to RLF or below (like China), growth will continue for some time as excess" people in younger age groups reach reproductive age. 4

5 RLF in Europe Average fertility rate is 1.4, substantially < RLF. Concerns about availability of future workers and taxpayers have prompted several countries to offer incentives for couples to have children at an earlier age. RLF in the United States U.S. population is fastest growing of all industrial nations. U.S. fertility rate is only ~2.0, actually below RLF However, immigration is adding people rapidly. Uneven Distribution Developing" nations have rapidly growing populations (birth rates vastly exceed death rates) Low incomes and the need for many children to raise family income or produce food. Knowledge of and access to contraception is limited. 5

6 Uneven Distribution Despite the population reduction of some developing countries, zero population growth will not be achieved globally. The U.N. predicts a global human population of 8.9 billion in the year 2050 Population Age Structure If developing nations were to achieve RLF immediately, their population increases would continue for decades. A large population of children today create a momentum or inertia for future growth as they enter their reproductive years. 6

7 Rapid population growth in the U.S. may have serious implications for the environment of the U.S. and the Earth. Americans consume far more resources and produce far more pollution than the global average The "ecological footprint," is more than four times greater for U.S. residents than the global average. A Quiz Question for You: Q: Which of the nations listed below has the lowest annual rate of increase (as a %)? A. New Zealand B. Australia C. China D. United States 0.7% 0.6% 0.5% 0.6% In Summary ? 2.? 3.? 4.? 5.? 7

8 Next Week s Quiz Next Friday Chapter # 26 Next Week.. Communities 8