Population growth rate is the change in size of a population over a certain period. It can either be a positive change or negative, which depends on the balance of deaths and births. Population growth can be measured in both relative and absolute terms. Absolute growth the difference between a population, in numbers, over time. Relative growth is a percentage or a rate.
The world population grew slowly upto about 1750 when death rates were higher than birth rates and life expectancy low. The rate of growth, however, increased since then upto 1970s. The global population is, however, declining significantly from its 1970s highs (Ernest 2000). This paper will discuss and explain in detail the causes of reduction in growth rate-fertility, technological development, human aspirations are the main factors. The paper will also show how the reduction in growth rate is not evenly distributed around the globe. It will also explain how the growth is expected to decline further in the future.
Economics and human aspirations largely control fertility. The developing world is not technologically advanced, and, therefore, needs a large number of manual labor to perform its tasks since most people in the developing world heavily rely on agriculture for survival. In this world, families with a large number of children will realize an enhanced economic status. As technology advances, they realize that having more children decreases their standard of living, and so reduce the number of children they get.
Fertility has, also, driven the current population significantly. Developed countries have a lower fertility rate than less developed countries. Therefore, in the developed world, fertility rates are almost of the replacement levels-meaning the population is approximately stable, while in the developing world they are much higher. Thus, the population growth is clearly links to the level of development.
Some countries showing declines have forced sterilization or contraception on their populations, for instance China where the government limits each couple to get one child. In Brazil, the Catholic Church ensured there is no state family planning program. This has not barred the millions of its women who have gone for sterilization clinics, which has halved fertility in 20 years to an approximate of 2.3. In Iran, during Mullahs ruling, the country declared strong opposition to most of the international agenda for reducing birthrates. However, women took care of their bodies back home and saw the fertility rate drop from 5.5 children per woman in 1988 to only 2.2 in 2000. Additionally, there are several countries in Africa that have established contraception programs and birth control campaigns and declined growth rate such as Kenya, Botswana and Zimbabwe (Ernst 2000).
Additionally, HIV/AIDS has been a cause of population decline. For instance, it has been a significant cause of deaths in South Africa and more countries in Africa (Rohleder 2009). While the epidemic spreads across the globe, it is wide spread and causes more deaths in Africa than any other continent. This is mainly because most of them still hold on to traditions and cultures, and do not have access to education and dependable health facilities. Also, lack of drugs for those infected due to poverty has been a significant contributor of deaths in the continent.
The decline in population growth is, however, not evenly distributed across the world. Moreover, some parts have had an increase in population growth over that period.
Years to come, the imbalance on population witnessed over the last century can only intensify. Virtually, most of the population growth will occur in the least developed countries. The U.S. and Canada will largely account for the small percentage of population growth expected for most developed countries, where most of the growth will be likely as a result of immigration from the less developed countries. While the less developed countries are projected to increase to 8.1 billion in 2050 from 5.5 of 2008, most developed countries will increase from 1.2 billion to 1.3 billion. The current estimates are a continued decline to an estimated 0.5 percent in 2050. Though the mortality rate is higher in the less developed countries, fertility rates in these countries are even much higher, thus account for relatively high growth rate in the third world countries (U.N 2004).
Mortality, especially due to HIV/AIDS pandemic persistence and other communicable diseases will be a leading cause of the declining growth rate especially in the third world. Secondly, experts expect the fertility rate to decline, which will eventually cause the population to grow slowly. The decline in fertility attributes to the ever-advancing technological changes in the third world and governments’ intervention in birth control in these countries. Economic stability will also aid in declining the population growth rate (UN 2004).
With the current environmental degradation and the exhaustion of natural resources due to high population, there are other causes of population growth decline that may be expected to come up. For instance, the destruction of the ozone layer can almost certainly be expected to cause extreme heat on the planet, thus causing disasters like drought, famine and winds in some parts of the world (Fenech 2005). This will eventually cause many deaths. It might also lead to the emergence of other communicable diseases.
In conclusion, from the above information, it is clear that population growth rate has been changing with time. Fertility decline, economic stability, developments, technological advances and AIDS pandemic are the main causes of this decline in population growth rate. The study also reveals that the growth has been different across the globe and that it is expected to decline more into the future. Other factors will emerge in the future. What is not clear, however, is whether the planet will be able to support the projected number of people expected to be living by 2190.