Population Trends

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During the 20th century, the world had the largest population growth ever. The population started at 1.6 billion people and at the end of the century, there were 6.1 billion people. There was however, a big disparity in population growth between underdeveloped regions and more industrialized, developed areas.

In 2006, the world population was at approximately 6.5 billion. There are different factors that have affected the increase in population around the world and the decrease of population in many underprivileged areas.

For instance, the AIDS epidemic has had drastic effects in areas such as Swaziland, Botswana and Zimbabwe. Because of the epidemic, there has been a drastic increase in mortality and the life expectancy of people in these areas has declined.

The below information was taken from: http://209.85.165.104/search?q=cache:DrMNW1j136AJ:www.population-growth-migration.info/population.html+trends+population+growth&hl=en&ct=clnk&cd=6&gl=us

Since about 1750, the world population has grown massively, at an increasing rate until recently, from some size of the order of 500 million, to over 6 billion now. In the 'industrialized' or 'developed' world, during this period of population growth, national populations have largely completed going through what is called the 'demographic transition' (see graph above). This is the transition from a largely rural agrarian society with high fertility and mortality rates, to a predominantly urban industrial society with low fertility and mortality rates.

In the industrialized countries, generally speaking, the transition began with a large drop in mortality rate. Only much later did fertility rate decline, so the decrease in mortality rate allowed a massive population explosion. Then with the later decline in fertility rate, the population growth slowed down and has or will soon cease (we ignore here the effect of possible high future immigration). It can be seen then that there are two key transitions within the 'demographic transition' - first a mortality transition and second a fertility transition.

The underlying causation of the demographic transition was complex; various factors were involved, such as changes in modes of agricultural production and improvements in hygiene. The timing and details of the transition however, varied considerably between countries, and in Europe, between different regions. And in France, where fertility declined relatively early, there was no big time gap between the onset of mortality decline and the onset of fertility decline (R5).

It is worth noting at this point the meaning of two much used demographic terms. First, the Total Fertility Rate (TFR). This is the number of children that would be born to a woman if current patterns of childbearing persisted throughout her childbearing years (usually considered to be ages 15 to 49). Second, The Replacement Fertility Rate (RFR). The RFR is the fertility rate that will ensure that each woman will be replaced by one daughter in the next generation (it is only women that add the males as well as the females to the population!). In developed world countries the RFR is a little over two rather than two because, first, slightly fewer girls are born than boys, and ...