BIOL 2804 Lecture Notes - Lecture 22: Paul J. Crutzen, Atmospheric Chemistry, Infant Mortality
29 Dec 2019
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Document Summary
Human population growth 8,000 bce to present: current world population 12/3/19: 7,748,177,710 (7. 7 billion) Increase per unit time expressed as a percentage of population: depends on births and deaths, example: 100 people, 10 born, 5 die, gr = 5/100 = 5% Current projection is that growth rate will level off around 2100 with a world population of about 11 billion. Potential social factors contributing to fertility rate of human populations: urbanization, economic development, the richer the people, the lower the fertility, changing roles and education of women. Increasing education for women is strongly linked to lower fertility. Ecological factors limiting population size: atmospheric carbon dioxide, food supply, availability of freshwater. How much food can we produce: net arable land has not increased since 1960 (1. 4 billion hectares) If everyone ate average us omnivorous diet, land could feed up to 2. 5 billion. If everyone becomes vegetarian, land could feed up to 10 billion (only growing grains)
