Topics in Population GeographyPopulation geography is a large branch of geography that contains several different topics related to the world's population. The first of these is population distribution, which is described as the study of where people live. World population is uneven as some places are considered rural and are sparsely populated, while others are more urban and are densely populated. Population geographers interested in population distribution often study past distributions of people to understand how and why specific areas have grown into large urban centers today. Usually, sparsely populated areas are harsh places to live such as Canada's northern territories, while densely populated areas like Europe or the coastal United States are more hospitable.
Closely related to population distribution is population density - another topic in population geography. Population density studies the average number of people in an area by dividing the number of people present by total area. Usually these numbers are given as persons per square kilometer or mile.
There are several factors which affect population density and these are often subjects of population geographers' study as well. Such factors can relate to the physical environment like climate and topography or be related to the social, economic and political environments of an area. For example, areas with harsh climates like California's Death Valley region are sparsely populated. By contrast, Tokyo and Singapore are densely populated because of their mild climates and their economic, social and political development.
Overall population growth and change is another area of importance for population geographers. This is because the world's population has grown dramatically over the last two centuries. To study this overall subject, population growth is looked at via natural increase. This studies an area's birth rates and death rates. The birth rate is the number of babies born per 1000 individuals in the population every year. The death rate is the number of deaths per 1000 people every year.
The historic natural increase rate of population used to be near zero, meaning that births roughly equaled deaths. Today however, an increase in life expectancy due to better health care and standards of living has lowered the overall death rate. In developed nations, the birth rate has declined, but it is still high in developing nations. As a result, the world's population has grown exponentially.
In addition to natural increase, population change also considers net migration for an area. This is the difference between in-migration and out-migration. An area's overall growth rate or change in population is the sum of natural increase and net migration.
An essential component to studying world growth rates and population change is the demographic transition model - a significant tool in population geography. This model looks at how population changes as a country develops in four stages. The first stage is when birth rates and death rates are high so there is little natural increase and a relatively small population. The second stage features high birth rates and low death rates so there is high growth in the population (this is normally where least developed countries fall). The third stage has a decreasing birth rate and a decreasing death rate, again resulting in slowed population growth. Finally, the fourth stage has low birth and death rates with low natural increase.
Graphing PopulationIn addition to studying the specific numbers of people in places throughout the world, population geography often uses population pyramids to visually depict the population of specific places. These show the numbers of men and women with different age groups within the population. Developing nations have pyramids with wide bases and narrow tops, indicating high birth rates and death rates. For example, Ghana's population pyramid would be this shape.
Developed nations usually have an equal distribution of people throughout the different age groups, indicating slowed population growth. Some however, show negative population growth when the number of children are equal or slightly lower than older adults. Japan's population pyramid for example, shows slowed population growth.
Technologies and Data SourcesPopulation geography is one of the most data-rich fields in the discipline. This is because most nations conduct comprehensive national censuses around every ten years. These contain such information as housing, economic status, gender, age and education. In the United States for example, a census is taken every ten years as mandated by the Constitution. This data is maintained by the U.S. Census Bureau.
In addition to census data, population data is also available through government documents like birth and death certificates. Governments, universities and private organizations also work to conduct different surveys and studies to gather data about population specifics and behavior that could be related to topics in population geography.
To learn more about population geography and the specific topics within it, visit this site's collection of Population Geography articles.