LITE6_-_study_guide - Study Guide Chapter 6 - The Human...

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Study Guide – Chapter 6 - The Human Population and Its Impact The book cites three reasons for the rapid rise in human populations, the ability to colonize almost all biomes on the planet, agricultural production, and medical discoveries. Even though the growth rate has slowed to 1.22% (doubling time of 57 years), we are still adding 82 million people a year to the world’s population. Note the ways this population growth has affected the planet’s resources and ecological functions (Figure 6-A); how close are we getting to the environmental limits of human population growth? I think this is the wrong question; a more important question is what quality of life do we want to have for people on the planet ? If we want clean air, clean water, abundant resources, biodiversity, and functioning ecosystems, then how many people do we need? My guess is that it is significantly lower than the environmentally-determined limit; can we have a healthy planet with the middle projection of 9.3 billion people by 2050? The book phrases this idea as a cultural carrying capacity , and this is much more to the point; if the world in general wants to enjoy the lifestyle of the developed countries, then we probably need to stabilize populations well below 9.3 billion. Populations change according to migration of people around the planet, the birth rate (number of babies born per 1000 people per year), and the death rate (number of deaths per 1000 people per year). As you can see in Figure 6-3, the most populous countries will not change in order by 2050, but all will have significantly more people, 31% will live in China and India (if we get to 9.3 billion); how will this effect global politics, global economies, and global resources? Note that the replacement-level fertility rate is about 2.1-2.5 (due to juvenile mortality), and the total fertility rate (the average number of children born to women during their reproductive years), although down, is still 2.6 as of 2008, well above replacement. The population in the
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This note was uploaded on 10/02/2011 for the course RNR 1001 taught by Professor W.kelso during the Fall '08 term at LSU.

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LITE6_-_study_guide - Study Guide Chapter 6 - The Human...

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