world population growth rate for 50 years (1900-1950) is only 0.8%. However, since 1950, the growth rate has increased rapidly. According to the U.N. World Population Prospects shown in table 2, from 1950 to 1955 the growth rate was 1.78% and it rose to 2.04% for the five year period from 1965 to 1970. By looking separately between the more developed and less developed regions, the annual population growth rate of 1965 to 1970 for the less developed regions (Africa, Asia excluding Japan, Latin America, Oceania excluding Australia and New Zealand) was 2.52%.
In this connection, the growth rate for the more developed regions (Europe, North America, Japan, Australia, and New Zealand) for the same period was 0.82%. If the world population increases at the rate of 2.5% for the coming 850 years, as Coale(Ansley J. Coale) figures that the total weight of all mankind will become equal to the mass of the earth. This shows the problem with the growth rate of developing region these days. The reason behind the increase of the world population growth rate at such a high percentage as 2.04% is that the death rate, which was quite high before the war in developing regions that made up 2/3 of the world population, dropped drastically by the after effects of the medical revolution taken place in Europe and Northern America while the birth rate stayed as high as before. In other words, natural growth rate was expanded.
However, after the period of 1965 to 1970, the world population growth rate started to decline. The rate dropped down to 1.73% for one time for the period of 1975 to 1980, but for 15 years from 1975 to 1990, it kept at the same level. Though there is no room for a detailed explanation of the causes, the drop of the death rate in developing regions while the birth rate in both the more developed and less developed regions is dropping still has a great effect. However, from the period of 1990 to 1995, dropping of growth rate has been seen and as table 2 indicates, it is estimated that the rate will drop down to 1.00% for the period of 2020 to 2025.
However, lately the population growth does not show a decline even though the world population growth rate is declining. As table 2 clearly shows
