Evolution of world's population

Population growth refers to change in the size of a population—which can be either positive or negative—over time, depending on the balance of births and deaths. If there are many deaths, the world's population will grow very slowly or can even decline.
The world population has grown tremendously over the two past centuries, but before this situation was not the same.

Evolution of world's population

Until about 1750 population grew very slowly because there was a counterbalance between high mortality and high fertility. At the dawn of the first millennium world's population was around 300 million people due to a long period of stationary growth. In the next years population grew slowly and we have estimated it was around 800 millon in 1750. World's population was kept in check by high death rates due to the combined effects of plagues, famines, unsanitary living conditions, and general poverty. For example, we could mention that european population even fell in the 1300s -killed by the Black Death.

By the mid 18th century living conditions changed in western Europe due to the Industrial Revolution, and population began to grow substantialy: by 1950 it had tripled to around 2.5 billion people. The use of antibiotics and other public health advances worldwide allowed a more dramatical increase: by 1985, the human population was 5 billion. By 2000 global population was 6 billion ant is projected to be 9 billion in 2050. Link