• Population geography provides the background concepts and theories to understand and forecast the size, composition, and distribution of the human population.

• Demography, the statistical study of the human population, is concerned with spatial analysis—location, density, pattern, and relationship to the physical environment.

4.1 Population Growth

• In 2017, the population hit 7.5 billion and added an extra 230,000 thousand humans a day.

  • It took all of human history to about the year 1800 to reach 1 billion and another 130 for the next billion.

  • In 1962, the globe was supporting an extra 2.1 percent which has slowed down to 1.1 percent today.

  • It is predicted that 9.8 billion people will live on earth by 2050, and 9.5-13.8 billion by 2100.

  • Though it is agreed that all the growth will continue in the least developed countries of the world.

• Some people believe that the growing population will create solutions to the resource shortages while others are not as enthusiastic as the population already expanded 4 times between 1900 and 2000.

  • More people will put a strain on the earth and damage the earth with pollution and the increased need for resources.

4.2 Some Population Definitions

• Rates simply record the frequency of occurrence of an event during a given time frame for a designated population

• A cohort is a population group unified by a specified temporal characteristic—the age cohort of 0–4 years, perhaps, or the college class of 2025

• The crude birth rate (CBR), often referred to simply as the birth rate, is the annual number of live births per 1,000 population.

  • 40,000 births/2,000,000 population = 20 per thousand

  • Lots of developing countries had a lower birth rate as the population growth is slowing down.

    • Things like the birth control pill have decreased rates

• The total fertility rate (TFR) is a more refined and thus more accurate measure for showing the rate and probability of reproduction among fertile females, the only segment of population capable of bearing children.

  • The concept of replacement level fertility is useful as it can be used to see how many kids a family would need to replace the parents and balance the population.

    • It is around 2.1-2.3 because of mortalities and other tragedies.

    • More than half the world lives in countries with a TFR of 2.1 or less

      • China dropped from 5.9 in the 60s to 1.8

• The crude death rate (CDR), also called the mortality rate, is calculated in the same way as the CBR: the annual number of events per 1,000 population.

  • Antibiotics and advancements in science decreased death rates.

• The infant mortality rate is significant because that is where the greatest declines in mortality have occurred.

  • 20-30% of infants would not reach the age of one in the 1800s but now it is in the single digits due to clean water, sanitation and diseases not being much of an issue.

• A population pyramid is a powerful means of visualizing and comparing a population’s age and sex composition.

  • It is an easy way to visualize data.

4.3 The Demographic Transition Model

• Exponential population growth cannot continue on a finite planet.

  • If the population is not voluntarily controlled, famine, disease or resource wars may occur.

• The increase in population was quite slow and was not steady as famine, war and disease were very common.

  • There were high death rates and high birth rates

  • From the 1750s and on the birth rate continued to stay high but the death rates slowed down which caused an increase in population.

  • Then after the industrialization revolution life expectancies went up, medicine got better and food was not affected by crop failures and such.

• Today, birth rates are declining because people are starting to see that children are very expensive and since the death rate is lower parents are okay with fewer kids.

• Sanitation and medicine decreased the death rates and mortality rates which led to the sudden increase in population between the 1800s and 1900s, but the growth has slowed down in first-world countries.

4.4 The Demographic Equation

• Change in population occurs when someone is born, migrates or dies.

  • Pf = Pi + births + in-migration - deaths - out-migration.

    • Pf being the final population and Pi being the initial.

4.5 World Population Distribution

• The world’s population is not equally distributed.

  • The rural population separated from the urban population until 2007 when more than half the world began to live in cities.

• 88% of people live above the equator.

  • ⅔ of that live between 20 and 60 degrees north.

  • More than half the people live in 5% of that land.

  • People also live at lower elevations due to the availability of fertile land and oxygen.

  • There are 4 large clusters of population

    • South Asia, East Asia, Europe, and the northeastern United States/southeastern Canada.

• “Ecumene” is a word used by the ancient greek that means permanently inhabited land

  • To expand this the land irrigation, terracing, diking, and draining are all techniques used by humans.

• “Nonecumene” is the uninhabited land

4.6 Population Density

• The term population density expresses the relationship between the number of inhabitants and the area they occupy.

• This is a useful statistic when calculating the density between smaller land masses

  • New Jersey has 467 people per sq km and Wyoming has 2 per sq km but the entire country has an average of 32 per sq km.

• The physiological density provides a measure of the population pressure exerted on agricultural land.

• Agricultural density, simply excludes city populations from the physiological density calculation and reports the number of rural residents per unit of agriculturally productive land.

• Overpopulation refers to the situation in which an environment or territory cannot support its present population and involves many factors other than just population density.

  • Someone from Wyoming may think New York is overpopulated vice versa.

4.7 Population Data and Projections

• The data that demographers use come primarily from the United Nations Statistical Office, the World Bank, the Population Reference Bureau, and ultimately, from national censuses and sample surveys.

  • The data are far from perfect. In developing regions, isolation and poor transportation, insufficiency of funds and trained census personnel, high rates of illiteracy limiting the type of questions that can be asked, and populations suspicious of government data collectors serve to restrict the frequency, coverage, and accuracy of population reports.

  • Lots of births and deaths are missed all throughout developing countries.

• Demographers use old and outdated data to make predictions for the future due to the incorrect and outdated methods of data collection.

• People have worried about over populations for thousands of years and have tried to calculate the perfect amount for a given amount of space.

  • All humans can fit in a small space. The number of resources humans use and waste they produce shows why there’s a cap on how many can comfortably live.

• In the 1800s, people believed that the earth would not be able to sustain the number of people there and believed that the only way to support more was to grow more food.

  • All these estimates were incorrect as technology increased the carrying capacity of the planet.

4.8 Population Prospects

• The birth rates of the developing world are slowing at a rate that was never predicted

  • This means that the world population could peak sooner than predicted.

• In the 70s Europe’s birth rate dropped below the replacement value

  • The countries decided to reward pregnancies with free healthcare, extended maternity leave, and child care.

• Many of the developed countries are below the replacement value and Europe is supposed to shrink in size.

  • This is because of the expenses of children, people not wanting them, and cultural expectations are not the same as they were.

• Throughout all of history, younger people outnumbered the elderly.

  • This has changed as people above 65 now outnumber those under the age of 5.

• By 2050 the elderly are supposed to make up 20% of the population compared to 8% in 2000.