Introduction
We often hear about our global population growing exponentially which will result in a drastic overpopulation and crises. I am here to tell you that this way of thinking is over simplified and no approximation of the reality. I am not making any statement on how many people the earth can carry while being sustainable, but I will try debunk the myth of the exponential population growth.
Demographic transition
The demographic transition is a model that approximates the population growth during the evolution from an agricultural based society to a "modern" industrialized one. In this transition there are four important stages, the first one is an agricultural society, the second one is a transitional stage, the third one is an industrialized stage and the fifth stage is post-industrial.
First stage of the transition: Pre-Industrial
In the first stage of the transition we can find countries, or regions that have not been industrialized. This stage also includes western countries before the 18th century. Economic activity is based on agriculture and mortality rate is rather high due to lack of technological advancements or economic wealth. Since mortality rates are high due to disease, famine and poor medical knowledge, families needed many children as they can help on the field and provide a certainty when the parents get old and need assistance during the late part of their lives. Therefore birthrates are also high to make sure enough children stay alive to care for them, resulting in a constant population size.
Second stage of transition: Transitional
In this stage, industrialization is starting to emerge but is not yet fully developed, it starts with the mechanization of agriculture. We see many improvements in peoples lives such as increased agricultural output, more medical knowledge, sanitation etc. This increases the life expectancy and decreases the mortality rate. Birthrates on the other hand don't drop, because the people that live longer still have the mindset that many children are necessary as in the previous stage. because of this decline in mortality while the birthrate stays high, population expands rapidly.
Third stage of transition: Industrial
Finally industrialization is at its peak. Technological advancements have lowered the mortality rate even further and in this stage birthrates start to decline. Mentality changes and further lowering of the mortality rate made less children necessary in a family and population growth starts do reduce.
Fourth stage of transition: Post-industrial
During this stage health care is at its best, food supply is reliable, more and more women are being educated and get married at a later age. Mortality rates have dropped to a minimum and now birthrates have too. The population is stable again without any growth. Economic activity also shifts from industry to services.
Fifth stage of transition?
There is a possible fifth stage of the transition, but not many countries are this far to observe the characteristics. We see that in some countries birthrates have dropped even more, leading to a decrease in population.
Why is there still a population peak now?
While most western countries have already been trough this transition, many countries are still undergoing the process and have rising populations. These grow much faster than when western countries went trough the transition because new technologies lower the mortality rate almost instantly because they already exist, while these technologies had to be discovered and developed over time in other western countries.
Conclusion
As population growth might look exponential, it actually is in the middle of a global transition from high birth and death rates to a world with low birth and death rates. eventually there will be a halt in population growth according to this model. When this will be the case is worth a discussion on its own but we can rest assure it will be there eventually.