Demography is the study of population changes. I will describe two general views, the Neo-Malthusian and the Modernization view, on the matter, starting with the former.
Thomas Malthus, a late demographer and economist, believed that food production would increase over time but not as fast as population growth.
In his studies, he assumed that love (sex) and food was necessary.
The Neo-Malthusians believe that population growth is the main problem, not only because it will outrun food production but also since it is a threat towards the environment and therefore the base of survival.
The remedy, according to the Neo-Malthusians, is to reduce population and population growth (family planning).
The Modernization theory says that the main problem is economic and social backwardness, thus making population growth occur. If there is economic development the population growth will decrease instantly.
The remedy is therefore is economic and social reforms.
What does history explain?
Colonisation took place in the 16th century and onwards. Trade posts were established along the coasts. Europe started a globalized trade (such as the Triangular Trade) which sent profits back to Europe.
This led to industrialization in Europe in the 19th century. A dependency upon export in the Americas and in Africa was developed since the industrialization in the colonies was prohibited.
The slave trade in Africa created wars and destroyed the already existent local trade. Since slaves often were young and productive women and men a drainage of young workers was created.
Imperialism (1870 – 1914)
During the so called second phase exploatation was intensified, the interior of the continents were penetrated. European industry needed cheap raw materials such as copper, rubber, cotton and food.
Capital profits from industry in Europe needed new investment projects which were found in the colonies.