PDS AP Environmental Science 8th Period 2010-11

So, this is a nice 3 minute video by National Geographic that ties together ideas from Unit 6 and 7.  Lots  of humans on the this planet, and they are migrating to urban areas…

Are you worried?

Since many of you enjoyed seeing Hans Rosling’s first TEDTalk, I thought you might enjoy seeing his most recent.  This one was given on 10/7/2010 and is called “The Good News of the Decade” and is about the battle against child mortality…and using averages when discussing Africa.

*Note: We only got to spend a few minutes discussing this topic the last day before exams, so I am including this nice post by IanN from last year.

There are two “Human Population Problems” that we discussed in class:

1. The Annual Growth Rate (AGR) of a population is too high, leading to problems with overpopulation.
2. The AGR of a population is too low, leading to problems involving supporting a “graying,” or aging overall population.

Big Picture: How to responsibly address an AGR that is too high.

There are 3 primary methods to addressing an Annual Growth Rate that is too high:

1. Family Planning: This doesn’t just include things like the government handing out condoms. Governments can fight high population growth by promoting sex-ed courses that help people in the community learn how to practice safe sex and avoid unwanted pregnancies. A good example of this method being used would be Thailand, where family planning programs helped to reduce the AGR from 3.2% in 1971 to 1.6% in 1986.
2. Industrialization: Most high AGRs come hand-in-hand with poverty. The poorer a nation’s population is, the less likely it is that the people in the population will use birth control or other means to avoid unwanted pregnancies. By industrializing, a nation increases its Gross Domestic Product (GDP), which in turn allows its population to raise its standard of living by making more money. As a population increases its standard of living, it will begin to be more cautious when it comes to sexual practices, causing its AGR to go down. Many Asian countries helped to reduce their AGR by industrializing and increasing their GDP.
3. Improve Education and Opportunities for Women: One of the biggest causes of a high AGR is the inability of the women in a population to have a say over how many children they have. In these societies, the men essentially decide how many children a woman will have, and a large amount of children (especially sons) is often seen as a positive thing. If women in these societies were to be given greater opportunities, they would be able to get better educations, become working members of society, and get a much greater say in the number of children that they bear. By empowering women, a nation is able to greatly reduce its population’s AGR.

What Can One Nation Do to Regulate Its AGR?

A nation can use policies, laws, regulations, and taxes to help control the growth of its population.

• China cut its Crude Birth Rate (CBR) in half by implementing its One Child Policy in 1972. This is one of the strictest  programs in the world. The government gives a ton of incentives such as extra food, larger pensions, better housing, free medical expenses, free school tuition, and salary bonuses to parents who follow the One Child Policy. After the couple has had one child (or two children in select cases), either the woman is required to wear an intrauterine device that greatly reduces the chance of pregnancy or one of them is required to be sterilized. If a couple chooses not to follow the policy, they are faced with a series of penalties, including fines, loss of land grants, and even discharge from the Chinese Communist Party.
• Countries could use tax deductions and tax credits to control AGR. In short, if AGR is too low, the government can offer to reduce people’s taxes if they have more children, and if AGR is too high, the government can offer to reduce people’s taxes if they get sterilized . Tax deductions are expenses you are allowed to use to reduce your gross income that affects how much you are taxes, while tax credits are amounts subtracted directly from the amount of tax you already owe.
• Governments can also use rebates to control a population’s AGR. Rebates are direct payments from the government to you, and can be given in exchange for a couple either having more children or having less children. You are probably most familiar with the rebates that are offered to you after you buy something in a store.

Original post at: http://pdsblogs.org/pdsapes810/2009/12/07/scribe-post-population-solutions/

How can you tell if a country might be sliding back to stage 1 or is in stage 3. Both populations seem to be staying fairly constant for age groups under 20 or so. Is the difference that a “sliding” country would have more population at a younger age that is constant than the decreasing older generations (this kinda looks like a trouble game piece) and a stage 3 country would have less people at the younger ages but still with a constant growth rate(this would make a shape like a mushroom)?

If you enjoyed the TEDTalk by Hans Rosling, I wanted give a chance to learn more about his work.

First, here is yesterday’s video if you want to watch it again:

Second, if any of you are interested in more about the stats in the presentation go to Dr. Rosling’s web site:
http://www.gapminder.org/
Explore the links and the tutorial. You can study these demographic trends for yourself-you can test ideas in the book by building your own graphs (Gapminder World). Here is one I gave out in class:

Click to Enlarge

*Maybe you are in a global studies class and need research displayed in a very cool format?

Third, here is another 18-minute TEDTalk Hans Rosling gave in 2007 on myths about poverty:

What do you think of Dr. Rosling’s presentations?

http://geographyfieldwork.com/g427.gif

Today in class we talked about the Demographic transition. We used this model to discuss how countries change over time to fit our four stages.

The four stages were:

1. Pre-Industrial: Countries without industry. Usually don’t have a centralized gov’t system (usually tribal). We didn’t find many (if any) countries that fit this stage.
2. Transitional: These countries are in the transition stage between Pre and Industrialized nations. They are characterized by high birth rates, and high death rates that decrease over time. These death rates decrease over time because the country starts to gain the ability to defeat death through medical advancement (anti-biotics and vaccinations) as well as sanitation and readily accessible food resources.  Countries like Rwanda and Ethiopia fit this model.
3. Industrial: This stage describes nations who have low death rates and birth rates that are lowering towards 0% population growth, but aren’t quite their yet. Countries like China and India fit this stage.
4. Post-Industrial: This stage describes countries that have low death rates, high life expectancy, and an AGR of zero or even negative %. Germany and Japan fit this model.

our class Stages

These are the notes on the different factors which can be responsible for raising or lowering the birth and death rate of a nation. If you have any questions regarding what is here, let me know!

Rate of Natural Increase = CBR – CDR/10 = AGR % (ignoring migration)

CBR/TFR/RF = Birth Factors:

Infant mortality rate (up) = Births (up)

Contraceptive availability (up) = Births (down)

Abortion (up) = Births (down)

Industrialization (up) = Births (down)

Value of child labor (down) = Births (down)

Cost of raising kids (up) = Births (down)

Women’s rights (up) = Births (down)

Average age of marriage (up) = Births (down)

Religion/culture/government = WILD CARD

CDR/IMR/LE = Death Factors:

Medicine advances (up) = Deaths (down)

Sanitation (up) = Deaths (down)

Conflict (up) = Deaths (up)

Epidemic (up) = Deaths (up)

In class on Friday we began discussing human population. We started by watching this video that illustrated the human population growth since the beginning of recorded history:

We just finished studying population ecology, how populations grow, and how they impact the environment and now we are moving into the human population and how it is growing and effecting the environment. The title written on the board was The Human Population – Our biggest environmental problem. Some people say that human population is at the core of environmental problems. Why? What are human impacts? We started with the human population size and growth.

The current human population is at 6.8 billion. How did the population get there? The human population grows like any other population we have studied and its current growth looks like a J or exponential growth curve.

Global Population Graph

#mce_temp_url#

This is a graph of the Global population over time. The human population grew low and slow until the Industrial revolution and modern medicine, when it took off. We dissected  the growth in class and when population reached each billion. 1800- 1st billion, 1930- 2nd billion, 1960- 3rd billion, 1975- 4th billion, 1987- 5th billion, 1999- 6th billion, 2010- 6.8 billion. Then we looked at the difference between each billion. The first billion took 1800 years to reach, the second took 130 years, the third took 30 years, the forth took 15 year, the 5th took 12 year, the sixth took 12 year, and we are almost at our 7th. There is a clear increase in the rate at which the human population grows but the amount of years between the billions seem to be becoming more constant which might indicate we are approaching an inflection point. Mr. Willard also told us that the AGR, or annual growth rate (also classed rate of natural increase), during 1960 was 2.1% and the AGR now is 1.2%, so the annual growth rate has decreased by almost half. AGR is related to doubling time, which is the time it takes for a population to double. When doubling time decreased the total population increases (learned the equation for calculating doubling time in class and it will be lower in the post) and right now the doubling time has decreased because the AGR has decreased.

The other part of class was spent learning equations needs for the human population unit. There are 3 basic type of problems for this unit. The first is doubling time by rule of 70. The doubling by rule of 70 equation is:

Rule of 70

In this equation the AGR has to be in percent form and then you divide 70 by that to get the doubling time. This is an example of one of those problems:

Doubling time by rule of 70 equation

So the AGR in this problem is 1.5% and the doubling time is 47 years. If the year was 2007 then, in this example, the population would double by 2054.

The second type of problem we learned was how to calculate annual growth rate. This equation is:

Annual growth rate equation

CBR stands for crude birth rate, which is births + immigration, and CDR stands for crude death rate, which is deaths + emigration. Crude means out of 1,000.  The original equation is ((CBR-CDR)/1,000) x 100, but the 2 zeros in the 100 and 1,000 cancel out and so the equation simplifies down to the equation you see above. This is an example of an annual growth rate problem:

Annual Growth Rate Problem

In this equation 14= crude birth rate, 9= crude death rate and the AGR come out as .5%.

The third type of problem we learn was annual increase. This type of problem is to find out how much a population will grow in a year. In this type of problem you are given a # for a population and the AGR(%) at the time. You use these to find how much the population will grow in the next year. In class we used the example that in 2007 there was a population of 300,000,000 and the AGR at the time was .5%. This is how to solve the problem:

We are not allowed to use calculators on the exam so in class instead of using a lot of zeros like in #1, we used scientific notation as illustrated in #3. For this equation  The AGR can not be in percent form for this problem the .5% turns into .005 or 5.0 x 10^-3 in scientific notation. You need to multiply the 300,000,000 or 3.0 x 10^8, the population, by the annual growth rate, and when using scientific notation keep in mind when multiplying numbers with exponents you add the exponents. So you get your result (when using scientific notation) by multiplying 3 by 5 and adding the exponents of the 10s, 8 and -3, which gives you 5. 15 x 10^5 (1,500,000 expanded). To get the total population after a year you just add the 1,500,000 to the total population of 300,000,000 and you have what the population will be, which in this case is 301,500,000.

That basically what we discussed and learned in class and the 3 types of problems we need to know. Keep in mind you can’t use calculators on the exam so brush up on your long division and stuff like that.