330 likes | 576 Views
Case study: China’s one-child policy. 1980. Human population growth: 7 billion. Human population growth: 7 billion. A few milestones that lead to our present population:. 10,000 bc agriculture 1500 new crops from Americas reach Europe 1798 vaccinations
E N D
Human population growth: 7 billion A few milestones that lead to our present population: • 10,000 bc agriculture • 1500 new crops from Americas reach Europe • 1798 vaccinations • 1850 sewers were separated from drinking water, which was filtered and chlorinated • 1884 contraception • 1930 better nutrition, sanitation, health care • 1960 Green Revolution
The human population is still growing rapidly 1350 Agricultural Revolution Hunter/ Gatherer Industrial Revolution
Result of Large Populations pollution Greater need for resources starvation Reduction in biodiversity
World population has risen sharply “baby boom” • Global human population was <1 billion in 1800. • Population has doubled just since 1963. • We add 2.5 people every second (79 million/year).
United States birth rate (births per 1000 population) Baby boom 1946-1964 1939-1945 WWII 1909 1919 1929 1939 1949 1959 1969 1979 1989 1999 2009
Rates of growth vary from region to region At today’s 1.2% global growth rate, the population will double in 58 years
Is population growth really a problem? Population growth results from technology, medical care, sanitation, and food. Death rates drop, but not birth rates. Some people say growth is no problem. New resources will replace depleted ones. But some resources (i.e., biodiversity) are irreplaceable. Quality of life will suffer with unchecked growth. Less food, space, wealth per person
Population and the Environment • Population growth can lead to environmental degradation. Overpopulation in Africa’s Sahel region has led to overgrazing of semi-arid lands.
Affluence and the environment • Poverty can lead to environmental degradation… BUT • wealth and resource consumption can produce even more severe and far-reaching environmental impacts.
Demography studies human populations Demography: the application of population ecology to the study of human populations Population size Density and distribution Age structure, sex ratio Birth, death, immigration, and emigration rates
Population size and density Predictions of population size depend on different assumptions about fertility rates.
Age Pyramid United States 2012 • The United States’ “baby boom” is evident in age bracket 40–50. U.S. age structure will change as baby boomers grow older.
Age structure: “Graying populations” Demographers project that China’s population will become older over the next two decades.
Age structure: “Graying populations” China’s aging population will mean fewer working-age citizens to finance social services for retirees. Figure 7.11c
China’s natural rate of change has fallen China’s rate has fallen with fertility rates. It now takes the population 4 times as long to double as it did 25 years ago.
Sex ratios 100 females born to 106 males China: 100 females born to 117 males
Population growth depends on various factors Birth Death Immigration Emigration Technological advances led to dramatic decline in human death rates. Widening the gap between birth rates and death rates resulting in population expansion
Factors affecting total fertility rate Urbanization decreases TFR. Access to medical care Children attend school and impose economic costs With social security, elderly parents need fewer children to support them. Greater education allows women to enter the labor force, with less emphasis on child rearing.
Family planning and TFR • Family planning, health care, and reproductive education can lower TFRs. A counselor advises African women on health care and reproductive rights.
The Earth can’t support our consuming lifestyle Humanity’s global ecological footprint surpassed Earth’s capacity to support us in 1987.
Longevity Lowest: Africa (55 years) and developing Oceania (64) years) Mortality Rates in Long-Lived Populations Age Adjusted Death Rates (per 100,000 people) Rank* Location Life Expectancy Eating Pattern CHD** Cancer Stroke All Causes 1 Okinawa 81.2 East-West 18 97 35 335 2 Japan 79.9 Asian 22 106 45 364 3 Hong Kong 79.1 Asian 40 126 40 393 4 Sweden 79.0 Nordic 102 108 38 435 8 Italy 78.3 Mediterranean 55 135 49 459 10 Greece 78.1 Mediterranean 55 109 70 449 18 USA 76.8 American 100 132 28 520 * Average life expectancy world rank** Coronary Heart Disease