An estimated 6.7 billion people lived on planet Earth in the year 2008. The change in the planet's population is affected by the number of children born and the number of people who die. The difference between these two numbers is said to be a natural increase in the population in the positive case and a natural decrease in the population in the negative case.

Mathematical models are used to make population forecasts. The world's population is said to grow exponentially, or in accordance with the interest rate principle. Even a small steady rate of growth doubles the population surprisingly quickly. For example, if annual growth were 4.0%, the world’s population would double in 18 years. Over the past decade, the growth rate has settled at 1.2% percent per year.

The population of Qatar has increased steadily starting from the 1970s. In the year 1950, the population of Qatar was around 25,000, but in 2017 it was almost 2,3 million. One reason for the high growth rate of the population is the high amount of expats moving to the country: around 88% of the people living in Qatar are foreign workers. The population seems to still be growing, and more and more people from around the world are moving to work and live in Qatar every year.

Only a finite number of people can live on a finite planet. If the world's population growth is not brought to a halt, the shortage of food, drinking water and other natural resources will increase. Stronger populations will defend their own interests and the living space they need, leading to subjugation of the weaker ones and, in the worst case, wars.

Half of the planet's total population growth takes place in six countries, namely India, China, Pakistan, Nigeria, Bangladesh and Indonesia. However, in Indonesia and China, the rate of population growth is actually slower than the average population growth rate of developing countries. In almost all developing countries, steps have been taken to control population growth. However, attitudes towards family planning are culturally dependent. In India, for example, family size is a measure of wealth and a guarantee of family social security. In China, the slowdown in population growth has been sought by giving parents of single-parent families wage increases and retirement benefits.