Dramatic population increase due to the lowering of death rates, causes:
- improved nutrition (imported corn and potatoes)
- scientific growth
- public health measures in colonies, too
- vaccinations and sanitation of areas
- wider availability of vaccines and drugs
- more women survived child birth
These improvements took place firstly in America and later spread to Europe, too.
The most successful efforts were made in the communist regime of China, where life expectancy grew from 30 years immediately after the 1949 revolution to 70 years in at the beginning of the 21st century. These result were obtained by guaranteeing the basic sanity measures and needs to all the population, while massively promoting a healthier and more hygienic lifestyle.
The crucial importance of children
At first, they were a liability: one mother had to give birth to many children in order to ensure at least few of them could survive to adulthood, also, they were extra people to feed and an expensive asset for a family. This trend stabilized later on, with better birth control measures.
A strongly uneven population increase all over the world. Before, occidental rich countries experienced higher birthrates but, with the the XXI century approaching, developing countries were the ones with more births.
A great struggle for rural areas: governments focused on massive food exports instead of stimulating local agriculture growth.
Famines started in the 70s in China, Russia, and Africa.
These great issues with food and supplies wasn’t helped at all by a massive urbanization, especially in south-east areas. Upheavals of struggling rural communities testified to this sentiment.
While in developed countries population growth and urbanization went hand in hand with a great improvement in industrial production, technology and welfare, in Third World countries the process was much more difficult, with a great polarization of wealth.
Of course, an uneven development lead to significant migrations all over the world.