Population growth is increasing exponentially especially in the rural areas. In the urban areas, migration from the rural areas is the root cause of the escalation of population growth.
What is important to reiterate is that less than twenty percent of the earth surface is habitable for human beings. Even in habitable areas their are striking contrast in the population densities.
Some places are roboost and highly populated while others are sparsely populated .The factors that influence population densities and pattern of population growth are as follows , namely; climate, soil, availability of water, etc.