We explain what population growth is and the types of population growth. What are its causes and consequences.
What is population growth?
Population growth or demographic growth is called change in the number of inhabitants of a geographic region determined over time. This term is often used to talk about humans, but it can also be used in the study of animal populations (by ecology and biology). Population growth is, then, the increase (or decrease, if negative) in the total number of individuals over a set period of time.
The study of populations and their dynamics of population change allows us to offer reasons and theories regarding the growth or decrease of populations, as well as to foresee their consequences in the short, medium and long term. Because It is the object of study of statistics and other specialized disciplines, as well as an important source of data to design social, economic, ecological policies, etc.
The world’s human population is a perfect example of sustained population growth, especially during the last century. From being 2,600 million in 1950 (when the UN was still young), in 1987 the number of humans on the planet reached 5,000 million, in 1999 6,000 million and in 2015 7,300 million. This global figure is expected to reach 8,500 million by 2030 and in 2100 the 11,200 million, if the current conditions were maintained.
Types of population growth
At first there are two types of population growth, one positive and one negative. We speak of positive growth when the population of the analyzed region has increased during the observed period, that is, there are more settlers. And, logically, growth will be negative when the population has lost settlers, that is, it has shrunk.
Causes of population growth
The causes of population growth can be diverse, such as:
- Fertility and health conditions. When a population reaches optimal health conditions, which allows it to live beyond reproductive age and expand families, birth rates generally increase, the population is fertile and reproduces extensively. On the other hand, when conditions are hostile, individuals prefer not to reproduce or reproduce little, or simply do not meet the minimum conditions to exceed reproductive age. Another important element is the infant death rate, which must be low to allow new individuals to grow, form and eventually reproduce as well.
- Longevity increase. If people live longer, they will be able to reproduce more and will also live to see their descendants reach adulthood, thus generating an elderly population.
- Migrations The arrivals and departures of individuals who decide to make their lives elsewhere (emigrants) or who come from other regions to the one studied (immigrants), not only contributes to cultural and genetic enrichment, but can also add new settlers or subtract individuals who They left.
- Changes in the quality of life in general. A thriving economy, a stable politics, a high demand for workers or a large market for the consumption of services are usually factors that generate immigration and positive population growth, since the inhabitants have a standard of living that guarantees them a future.
Consequences of population growth
Increasing population can bring many benefits, but also problems and unexpected consequences, such as:
- Increased demand for goods and services. Those populations that experience sustained positive growth over time begin to require more and more inputs to sustain the level of demand, which allows jobs to be filled, the economy to mobilize, but also to have greater competitiveness and to revive certain feelings of dissatisfaction (such as xenophobia).
- Exchange and cultural and genetic enrichment. Miscegenation is an enormous source of diversity and wealth. For this reason, populations that remain isolated for too long become culturally and genetically stagnant since they do not have a source of novel ideas or different genetic information (thus reducing the proportion of defects and mutations).
- Deterioration of the standard of living. When the host society cannot offer what is minimally necessary to migrants or new generations, an uncontrolled increase in the population can increase pollution, population density (causing overcrowding and scarcity of certain goods and services, which logically make them more expensive). ), or poverty.
Population growth rate
The population growth rate (PGR for its acronym in English) is the index that indicates the growth or decrease in the number of individuals of a given geography during a specific period. Using official figures obtained from local bureaucracy and registration apparatuses, it can be determined by applying the following formula:
Growth rate = (final population – initial population) / initial population
A positive growth rate indicates an increase in the number of inhabitants, while a negative indicates a contraction in the population. In either case, the population variation can be expressed as a function of the growth rate, that is, the percentage of variation:
Growth ratio = Growth rate x 100%
In those cases in which the growth rate is zero (0), we will be in the presence of a population in equilibrium: neither in population increase, nor in decrease. This means that the birth rate and mortality are equal.
Countries with higher population density
Population density indicates how much a specific territory is populated, assuming an average distribution of the population along its surface. The regions with the highest density are those with the least surface area per inhabitant, while the least populated will allocate a large surface area to each.
The most densely populated countries should not be confused with those with the largest populations; the former can present high densities due to their limited geographic dimensions, which allows them to have a relatively small population.
According to data from 2017, the seven most densely populated countries in the world are:
- Monaco. In Europe, with a density of approximately 19,307 inhabitants / km2.
- Singapore. In Asia, with a density of approximately 8,017 inhabitants / km2.
- Bahrain In the Middle East, with a density of 2,617 inhabitants / km2 approximately.
- Vatican City. In Europe, with a density of approximately 1,818 inhabitants / km2.
- Malt. In Europe, with a density of 1,387 inhabitants / km2 approximately.
- Maldives. In Asia, with a density of 1,188 inhabitants / km2 approximately.
- Bangladeshi In Asia, with a density of 1,145 inhabitants / km2 approximately.