Human Population Growth
Human population growth is a major topic in population ecology. Learn how births, deaths, immigration, emigration, demographic rates, and population density help explain how human populations change over time.
Human population growth depends on the same four demographic processes as other populations.
In This Article
What Is Human Population Growth?
Human population growth describes how the number of people changes over time. Like every population, humans are affected by births, deaths, immigration, and emigration.
Human population growth is also shaped by factors such as access to healthcare, sanitation, food, education, technology, economic conditions, and cultural patterns. These factors can change birth rates and death rates over time.
Population size changes when the number of individuals entering a population differs from the number leaving it.
Births, Deaths, Immigration, and Emigration
Four demographic processes determine whether a population increases or decreases.
Human population growth depends on the same four demographic processes as other populations.
Births + Immigration
New individuals are born into the population or move into it.
Deaths + Emigration
Individuals die or leave the population.
Birth Rates and Death Rates
A population's growth rate depends strongly on the relationship between its birth rate and death rate. When births substantially exceed deaths, the population can increase rapidly. When deaths approach or exceed births, population growth slows or becomes negative.
Human demographic patterns have changed over time. Improvements in sanitation, medicine, nutrition, and public health have helped reduce mortality in many populations. Birth rates may also change as education, economic conditions, family planning, and social structures change.
Why Human Population Growth Changes
Human population growth has not occurred at the same rate throughout history. Populations can experience periods of rapid growth followed by slower growth as demographic conditions change.
When death rates decline while birth rates remain high, population size can increase quickly. Later, birth rates may decline, changing the overall growth pattern.
A population can continue to increase even when its growth rate is slowing. “Growing more slowly” does not necessarily mean “getting smaller.”
Human Population Density
Population size and population density are different measurements. Population size is the total number of individuals. Population density describes how many individuals occupy a given area.
Humans are unevenly distributed across Earth. Climate, water availability, landforms, agriculture, transportation, economic opportunities, and historical settlement patterns all influence where people live.
High population density does not automatically mean a population is growing rapidly. Density describes how many people occupy an area; growth describes how the population changes over time.
Common Misconceptions
If You See This on a Test, Think This
Quick Practice
1. Which four processes change population size?
2. A country's population rises, but its growth rate falls. Is the population necessarily shrinking?
3. What is the difference between population size and population density?
4. How can improved healthcare affect population growth?
Key Takeaways
- Human population size changes through births, deaths, immigration, and emigration.
- Birth and death rates strongly influence population growth.
- Population growth can speed up or slow down over time.
- A decreasing growth rate does not necessarily mean a decreasing population.
- Population size and population density describe different characteristics.
- Human demographic patterns are influenced by biological, environmental, technological, economic, and social factors.
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