Human Population - More is Less
It is possible that the most pressing environmental issue of our time is the problem of human population growth. To see why this is so, we need to consider two aspects of human population growth: the quantity of human life and the quality of human life. First, consider the quantity of human life
Population growth occurs when the number of organisms entering a population exceeds the number of organisms leaving it. The population of a city, for example, rises if the people moving into it (immigration) plus the number of people born in it is greater than the sum of the number of people moving out (emigration) and the number of deaths. When considering the Earth, we need to consider in the birth rate (per 1000 people in a year in) as compared to the death rate (number of deaths per 1000 people per year).
For most of human existence, the death rate nearly equaled the birth rate, and the population grew very slowly (see human population growth graph p. 141). That is no longer the case. For part one of this activity the following growth rates are needed:
The World 1.8 % per year Africa 2.9% per year
Latin America 2.1 % per year Asia 1.9% per year
Canada 0.7% per year Europe 0.3% per year
Part I: Exponential Growth
Your group will be assigned a population growth rate, as a percentage. Using the growth rate you are assigned calculate the population for each of 40 years if 1000 individuals are present at the beginning. For example, if you were a assigned a growth rate of 7%, the calculation for the first two years would be done as follows: 1000 x 1.07 = 1070, 1070 x 1.07 = 1144.9. Round off your numbers to the nearest whole number. Graph your results.
Part II: Quality or Quantity
1. Look at the list of items below and decide whether each item used is generally “good” for people and the environment or is generally “harmful”. If it is good, place a “+” next to the item. If it is harmful place a “-“ next to the item. If you can’t decide, place a question mark.
| ___ clean water
___ over grazing ___ minerals ___ food ___ acid rain ___ crowded cities ___ available housing ___ opportunities for solitude | ___ energy
___ hunger ___ space to live ___ soil erosion ___ garbage ___ endangered species ___ international conflicts | ___ noise
___ luxury items ___ cars and roads ___ forests ___ poverty ___ contagious diseases ___ recreational space | ___ buildings
___ polluted air ___ unemployment ___ wildlife ___ oil spills ___ traffic |
2. Now consider the effect of a significantly increased human population on each item. Make two lists, one labeled “decrease” the other labeled “increase.” If increasing the human population would tend to increase the item write the item under the “increase” list. If increasing the human population would tend to decrease it, write the item in the “decrease” list.
Questions
1. Describe the effect of exponential growth on a population.
2. What sorts of things tend to increase with population increases? What sorts of things tend to decrease? In general, did the “good” things tend to increase or decrease with increased population? In general, did the “harmful” things tend to increase or decrease with increased population?
3. The United States has about 4.3% of the Earth’s human population and is responsible for about 30% of the annual resource use and pollution. What does this tell us about the lifestyle that is possible for the world’s population?
4. Which is more important, to halt population growth in the rapidly growing less developed areas such as Africa or in the more slowly growing developed areas such as the United States? Explain your answer.
5. List some advantages of reduced human population.
6. Discuss the importance of quantity of life vs. quality of life.
7. How does human population growth affect each of the following?
Extinction of other species, quality of air and water, space available for recreation, food available for people, stress and conflict, energy resources available per person, competition for jobs and housing, the spread of contagious diseases, your lifestyle in the next 40 years, your descendants’ lifestyles.
8. Should governments enact and enforce laws to limit population? Explain your answer.
9. Should governments encourage population control through such measures as education, tax incentives for smaller families, and making birth control more available? Explain your answer.
10. What can you do, personally, to help with the over population problem.
11. Was it surprising how quickly the population changed with only a small rate of growth? What does this tell about the world population?
12. How can a country’s birth rate decline yet its population increase?
Distinguish between a reduced rate of population growth and a reduced population.
13. How might population increases in more developed countries affect your life 10, 20, 30, or 40 years from now?
14. How might population growth in less developed countries affect your life 10, 20, 30, or 40 years from now?
15. How might population growth in our local area affect your life 10, 20, 30, or 40 years from now?