Sunday, October 3, 2010

Key issue # 4: Why might the world face an overpopulation problem?

The rate at which global population grew during the second half of the 20th century was unprecedented in history. This was due to a dramatic decline in the death rate. Scientists believe that the current rate of natural increase must be further reduced to prevent overpopulation.

Geographers observe that diverse conditions and environmental conditions may produce different answers in different places.

Malthus on Overpopulation:
He was one of the first to argue that the population is growing faster than the food supply, leading to a starvation pandemic. He thought that resources grew linear while population grew exponentially. His theory was proven incorrect because he never predicted that new technology would allow us to maintain a food supply that would sustain a growing population. Julian Simon believed that the human mind was the ultimate resource. Esther Boserup thought that population growth spurs technological innovations and that poverty is not caused by population growth.

Declining Birth Rates:
Even though the human population has grown at it's most rapid rate ever, world food production has consistently grown at a faster rate. the NIR declines due to lower birth rates or hight death rates. One way to lower the birth rate would be to improve local economic conditions. Another way would be to emphasize the importance of modern contraceptive methods.

Family Planning

World Health Threats:
Medical researchers have identified an epidemiological transition that focuses on distinctive causes of death in each stage of the demographic transition. This term comes from epidemiology, which is the branch of medical sciences concerned with the incidence, distribution, and control of diseases. A pandemic is a disease that occurs over a wide geographic area  and affects a very large proportion of the population.



This video shows how Japan's overwhelming population has forced them to make use of every inch of land they have. For example, they are building very tall buildings right next to each other to save space. They will need to make more changes if they want to avoid overpopulation. Many women are already using family planning and contraceptives. This means that they will be able to reduce the number of children they have.  

Key issue # 3: Why is population increasing at different rates in different countries?

A country moves from high birth rates and death rates, with little population growth, to low birth rates and death rates, with low population growth. During this process, the total population increases dramatically because the death rates decline before the birth rate does. The MDC's have slower growth rates while the LDC's have a period of rapid population growth.

All countries have experienced some changes in NI, fertility, and mortality rates, but at different times and at different rates. A similar process of change in a society's population is occurring known as the Demographic Transition.

Demographic Transition:
This process has several stages, and every country falls into one of them.
-Stage 1: Low Growth: There are very high birth rates and death rates. The burst of population in 8,000 b.c was caused by the agricultural revolution, which was the time when humans first domesticated plants and animals and no longer relied entirely on hunting and gathering.
-Stage 2: High Growth: There are rapidly declining death rates combined with very high birth rates. This produces a very high NI. Countries entered stage 2 after 1750 due to the Industrial Revolution, which led to a series of improvements in industrial technology that transformed the process of manufacturing goods. Also, the Medical Revolution in the 20th century pushed many countries into stage 2. Medical technology spread to the poorer countries and helped eliminate the traditional causes of death.
-Stage 3: Moderate Growth: Birth rates rapidly decline, death rates continue to decline, and NIR begins to slow.
-Stage 4: Low Growth: There are very low birth/death rates, no longterm NI, and possibly a decrease. In this stage the CBR= CDR, and the NIR reaches zero. This condition is known as zero population growth.

Population Pyramids:
Population in a country is influenced by the Demographic transition in two ways- the percent age of the population in each age group and the distribution of males and females. This info can be displayed on a bar graph called a population pyramid. The shape is mainly determined by the CBR. The most important factor of age distribution is the dependency ratio, which is the number of people who are too young to work compared to the number of people in their productive years. The number of males to females in the population is the sex ratio. In general, slightly more males are born than females.

Countries in the Different stages of the Demographic Transition:
Countries display different population characteristics depending on their stage in the demographic transition. There are no countries today that remain in stage 1.

Demographic Transition and the World Population Growth:
There are many countries in stage 2 or stage 3 of the demographic transition. These countries have a rapid population growth and only a few of them are likely to reach stage 4 in the near future.


In this article, it explains that MDC's have better technology and health standards, therefore they are able to control their population. But in may LDC's in Africa, they are unaware of the consequences and they do not have the same beliefs. For example, in the MDC's there are medicines and vaccines to treat illnesses and viruses. However, in LDC, they do not yet have the technology to produce these preventatives. These are a couple of the reasons explained in the article that affect population rates. 

Key Issue # 2: Where has the world's population increased?

Almost all of the world's natural increase is concentrated in the relatively poor countries.

Population increases rapidly in places where many more people are born than die. It increases slowly in places where the number of births exceeds the number of deaths. It declines when the number of deaths outnumbers births.

Natural Increase:
Geographers measure population change as a whole through crude birth rate, and natural increase rate. Crude birth rate is the total number of live births in a year for every 1,000 people alive. Crude death rate is the number of deaths in a year for every 1,00 people alive. Natural increase rate is the percent by which a population grows in a year. Very small changes in the NIR dramatically affect the size of the population. The rate of NI affects the doubling time, which is the number of years needed to double a population with a constant rate of NI.

Crude Birth Rate
Crude Death Rate
Geographers also use the total fertility rate to measure the number of births in a society. The TFR is the average number of children a women will have. The TFR for the world is 2.7. In LDC's, it may exceed 6 while in MDC's, it may be 2 or less.

Two measures of mortality in addition to the CDR include the infant mortality rate and life expectancy. The infant mortality rate is the annual number of deaths of infants under 1 year of age compared to the total live births. Poorer countries have higher rates while wealthier countries have the lowest rates. In general, the IMR reflects a country's health-care system. Life expectancy at birth measures the average number of years a newborn can expect to live. NI, CBR, TFR, IMR, and LE all follow similar patterns. MDC's have lower rates of NI, CBR, TFR, IMR, and a higher life expectancy. LDC's have higher NI, CBR, TFR, IMR, and a lower life expectancy.


This article explains through many charts and graphics that the world population is increasing in less developed countries more than in more developed countries. Most LDC's are in stage 2 of the demographic transition, therefore they have rapidly declining death rates and very high birth rates. This leads to a ripidly growing population in these regions.

Key issue # 1: Where is the worlds population distributed?

Global population is concentrated in a few places. Humans avoid area that are too wet, too dry, too cold, or too mountainous. The capacity of Earth to support a much larger population depends heavily on peoples ability to use sparsely settled lands more effectively.

Humans are not distributed evenly across Earth's surface. Geographers identify regions where population is clustered and where it is sparse, or spread out.

Population Concentrations:
Two-thirds of the world population is clustered in East Asia, South Asia, Southeast Asia, and Western Europe. This data can be displayed on a cartogram, which depicts the size of countries based population rather than land area. The four regions have some similarities that may explain why so many people live there. Most of these areas have easy access to an ocean or water supply, fertile soil, and a temperate climate.

Sparsely Populated regions:
Humans avoid clustering in certain physical environments. Few people live in regions that are too wet, too dry, too cold, or too mountainous. The portion of Earth's surface occupied by permanent human settlement is called the ecumene. Approximately three-fourths of the world's population lives in only 5% of Earth's surface.

Population Density:
Density can be defined as the number of people occupying an area of land. Geographers use arithmetic density, physiological density, and agricultural density to describe the distribution of people in comparison to available resources. Arithmetic density, or population density, is the total number of people divided by the total land area. Physiological density is the total number of people supported by a unit area of arable land, or land good for farming. The higher the physiological density, the greater the pressure that the people place on the land for food. Agricultural density is the ration of the number of farmers to the amount of arable land. This helps account for economic differences between regions.


This article provides information about population growth and how people are distributed across the United States. It states that many states population grew rapidly between 1990 and 2000 although they did grow at different rates. Also, it is stated in the article that most Americans lived in the states with the highest populations and that only 3% of the total population lived in the 10 least populated states.