EARTH122 Lecture Notes - Lecture 6: Environmental Degradation, Thomas Robert Malthus, Population Ecology
13 May 2016
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Document Summary
By 1970, china"s population had grown to 790 million people. In 1970, the government instituted a one-child policy, drastically decreasing the growth rate (now 0. 5%) It would take 30 years, counting once each second, to reach 1 billion. The human population is growing nearly as fast as ever. It took all of human history after 1800 - to reach 1 billion. In 1927, we reached 2 billion, and added the most recent billion in 12 years. Dynamics of population growth: exponentialgrowth- growth at a constant rate of increase per unit time. (geometric, arithmeticgrowth- growth at a constant amount per unit time. The human population is growing nearly as fast as ever (cont"d) At today"s 2. 1% annual growth rate, the population will double in 33 years (peak in 1960s, today more like 1. 2%) Rule of thumb to calculate doubling time (70/2. 1 33 years) If china"s rate had continued at 2. 8%, it would have had 2 billion people in 2004.
