Definition of Population Growth

Population growth has been in the news as the world's population has grown into the billions. Population growth is also a concern in developing nations that are struggling to allot their limited resources to increasing numbers of residents.

Definition

Population growth is the increase in the number of members of a population over a given time. A typical time frame for calculating growth is yearly. In the United States, the census tracks population growth over a 10-year span.

Factoring the Rate of Growth

The rate of population growth is determined by a simple formula: The population size at the beginning of the time period is subtracted from the population size at the end. That number is then divided by the population size at the beginning to yield a fractional answer, which is converted to a percentage.

Negative Growth

If the size of a population decreases over time, it is called negative population growth. A population may also experience no growth, though it is unlikely.

Factors

Immigration affects the size of a population (in more detailed formulas this is considered). Natural disasters, war or disease also impact population growth negatively. The Black Plague, for example, decreased populations in Europe during the Middle Ages.

Underpopulation

Although overpopulation is a well-known problem, underpopulation also creates issues. As the Baby Boomers aged, the population growth slowed. Those converged to cause a problem for the U.S. Social Security system, which relies on population growth to fund it. Japan faces a similar situation; with fewer people in the younger generation there may not be enough to take care of the elderly.

Resources

• World Population Growth Rates
• University of Michigan Lecture of Population Growth
• World Population Demographic Information