Population growth is the increase in the number of people in a specific region overtime period. Growth in population is measured using population growth rate which is defined as the percentage rate by which the number of persons in a population rises. “Population growth rate is used normally to refer to an increase or decrease in population over a period of time, usually denoted as the percentage of the number of persons in the population at the start of the period under consideration.” (Kreager, 2005, p. 130) A positive population growth rate indicates that the number of persons in that region is increasing, while a negative figure suggests the population is declining. a zero figure indicate the population in the two time period are the same; the population is the net difference between birth rate, death rates, and net immigration rates Overpopulation refers to growth in the population such that it exceeds the holding capacity of a region or environment. Overpopulation creates problems such as traffic congestion and pollution. If the population in a region or environment is small in that it can not maintain economic activities we refer to it as underpopulation. Population growth rate can be used to predict future growth in population although it may be uncertain to predict.
Population growth actually depends on several factors. Some of these factors can be estimated with certainty and include: first, Fertility rate which is the average number of kids that an individual woman will give birth in her lifetime– from puberty to menopause. The rate is averaged because not all women bear the same number of children and some even do not bear one. The second factor is the Age structure of the population. In most cases women give birth at ages between 15 years to 49 years; if the population has more women between this age and population growth is expected to be high. If the population consists of many children and old-age mothers, then the rate of growth of that population is sure to fall. Third, the Mortality rate, which is the number of deaths in the population of a society. Infant mortality rate measures the number of infants dying at age of one annually. These two rates are used by demographers to estimate the population growth rate. If the mortality rate is low then the society’s population will be high and vice versa. Finally, the Migration of people from one region to another affects the size of the population. The migration rate is measured as the difference between people arriving and leaving a certain region.
Some theories explaining growth in population: Malthusian theory advanced by Thomas Malthus, argued that population would result in societal chaos if its growth is not controlled. “He predicted that population will rose exponentially while food increases arithmetically and as result, the world will be faced with starvation.” (Ghosh, 2001) Second, Demographic transition theory; suggests three stages in the growth of population in alternative pattern, that is the stable—births and deaths rates are almost equal, rapid growth– death rates fall while birth rates remain high, stable—fertility falls as life becomes expensive and death rates fall.
As the population continues to grow, immense pressure is being exerted on agricultural lands, energy, water, and food. Insufficient food supply and inequality in food distribution have caused malnutrition in a rapidly growing population. The world population is currently standing at 6 billion people and is estimated to increase to 9 billion in 10 year’s time. Such increase will continue to increase pressure on the scarce resources available resulting in more human-wildlife conflicts.
References
- Ghosh, B. N. (2001) Fundamentals of population geography. New Delhi: Sterling Publishers Private.
- Kreager, Philip (2005). New light on Graunt. London: Population Studies, Vol. 42, No. 1 pp 129-40