As a population increase the resources become scarce. Therefore the alterations in number of births and deaths also decelerate. The human population has been growing persistently since the 1650, finally reaching a figure of 6 billion by late 1999 and 6.3 billion by 2003. Now whether this growth will continue consistently depends on ecological aspects. While ecologists might in certain circumstances feel that growth in human population might stop, in other cases they suggest that there is no permanent reason to restrain the growth. A rapid growth is supposed to have taken place owing to factors like a fast decline in death rate, modern techniques and processes of sanitation, an enhancement if growth of food facilities and distribution, improved medical care facilities and with time the improved living standards and higher level of income led the decline in birth rate to come to terms with death rate. In different European nations in 2003 the growth in human population has become negative or zero. As per the “medium variant forecast” of United Nations, a growth of zero percent is predicted for 2100. At that point of time, around 11 billion is the target population to be achieved. The population of the world reached one billion in 1850, two billion in another 100 years and 6.3 billion in 2003. As per Lomborg 60 percent of this growth would be skewed towards 12 nations. The regions outside Asian and African countries might not undergo the problems with population density. The population growth is highest in Asia where the zenith was achieved during 1989-91 with an addition of around 58 million births every year. The population growth has decreased gradually to 0.013 in 20032.
Each individual contributes another individual to the population, which can be called the per capita rate of increase. According to the ‘Essentials of Ecology’ population growth follows an ‘Exponential Growth Model’. The rate of per capita increase in the population can also