Human numbers have grown fourfold in the last century, from 1.65 to seven billion. They are projected to grow by a further four billion by the end of the century, driven by increasing longevity, a continuing high birth rate in some countries and population momentum, i.e. a historically high number of people of fertile age.
The story of our species is one of remarkable success. From a starting point in Africa, our ancestors spread across the planet, harnessing local resources and adapting to the harshest environments.
While some societies collapsed once they had exhausted local resources, and other groups migrated to new lands or fought wars over diminishing local resources, the overall picture was one of continued growth. As technological advances enabled our ancestors to increase agricultural output, their numbers grew exponentially.
The lack of open discussion about this topic means most people are not aware that our high numbers today are such a recent phenomenon. As recently as 1930, in our parents’ or grandparents’ youth, world population was some two billion compared with the seven billion living on the planet now.
The population trends projected by the UN vary enormously by region:
- Africa and much of Asia are predicted to grow significantly;
- the Americas are expected to grow somewhat; and
- Europe is predicted to stabilize.
The mid-range global projection is that the planet’s population will increase from seven billion to 10 billion by 2050. Broader estimates range from eight to 11 billion, depending on how effectively and quickly reproductive and development programmes are implemented in developing areas of the world to address the key drivers of population growth: the lack of reproductive health and contraception, lack of women’s rights and poverty. In some countries, migration also contributes significantly to the increase in population.
In the developed world, better reproductive health, contraception and women’s rights can also play an important role in reducing population growth.
Population growth rates worldwide are declining, but absolute numbers are still rising at one and a half million every week. Growth is also variable; populations are declining in some countries while continuing to grow rapidly in others.
Improvements made to infrastructure, wide availability of modern contraceptives and the empowerment of women all greatly contribute to significantly lower and therefore much more sustainable rates of birth.
Economic development also helps to lift women out of the high birth rate poverty trap.
Appropriate population goals must be set.