The impact of abortion on global population growth


I think we must consider the impact of abortion when discussing future population growth. Based on current data and the UN projected rates, the availability of abortion choice reduces population growth over the next eighty years by 43%, enabling the projected 11.2b rather than 16b, a reduction of 4.8 billion.


Our global population has been growing at an exponential rate, many of us would consider that it’s been growing at an alarming and worrying rate. In 1800, the population was just one billion, it is now more than seven and a half billion, (7,800,000,000). The rate of annual increase was 2.2% fifty years ago, but this has now slowed to 1.05% pa.

The UN projects that this rate of population increase will continue to slow, becoming just 0.1% in 2100, by which time there will be 11.2 billion people alive on Earth, a 40%+ increase over the next 80 years.

We already feel crowded and have concerns about eg the environment, health and social services, tensions between those of us who have enough and those who struggle. How will we cope with another 40% globally?

The number by which our population grows is the sum of total births minus total deaths. In 2020, there will be a projected 140m births and 60m deaths, so the population will increase by 80m. In 2099, the UN projects 130m births and 120m deaths, a population increase of 10m.

The number of births each year depends on the number of women of reproductive age (WRA) and their fertility rate. The total fertility rate (TFR) in 2015 was 2.49. This means that on average a woman who survives to the end of her reproductive years, age 49, will give birth to an average of 2.49 children, based on the age-specific fertility rates current in 2015.

TFR has been falling – in 1950 the global average was 5.05, in 1980 it was 3.7, in 2000 2.67, and it is projected to be 1.96 in 2099.

It is worth noting that a TFR of about 2.1 children per woman is called replacement-level fertility and is the level of fertility at which a population exactly replaces itself from one generation to the next.


There are many reasons for this reduction in the fertility rate. Max Roser provides a very helpful overview of the academic research attempting to answer the question, ‘why has the number of children per woman declined?’. This is accompanied by an excellent set of empirical data and analysis.

There’s little doubt that the halving of the TFR since 1950 has largely been because of the increased availability, accessibility, and affordability of modern, effective contraception.

I suggest that we must also consider the impact of abortion on this falling TFR, and on the number of live births. The WHO and the Guttmacher Institute estimate that in 2015 there were at least 50 million abortions worldwide. A small percentage of these will have been for cases in which the life of the mother was at risk, or in cases of rape or incest, or in cases of fatal fetal abnormality. In the UK, these cases account for ~3%, but for the purposes of this discussion let’s assume these are 10% of all abortions, the balance being the choice of the woman. On this basis, we could say that there is one abortion by choice for every three live births.

This is a significant factor in our consideration of the projected global population.

Without the choice of abortion, the TFR in 2015 would have been one third higher, 3.32 vs 2.49.

The Impact of Abortion on Global Population Growth

When we account for annual abortions, starting with 45m in 2021, and using the same rates of birth and of death as projected by the UN, we arrive at a total global population of 16 billion in 2100, which is double the current population and a 43% increase on the UN ‘medium variant’ projection of 11.2b.

I am not at all suggesting that abortion is a means of contraception, it clearly is not; nor am I suggesting that it should be considered as a method for family planning. I am saying that the continued choice to have an abortion will have a significant impact on the possible future size of our population.

When modelled based on the current data and the UN projected rates, the availability of abortion choice reduces population growth over the next eighty years by 4.8 billion. It’s a modelled projection and many of the underlying assumptions might of course change with time, eg the relative rate of abortions could be reduced with an increase in the uptake and improved use of effective contraception.


Max Roser, Hannah Ritchie and Esteban Ortiz-Ospina (2020) – “World Population Growth”. Published online at Retrieved from: ‘‘ [Online Resource]

Max Roser (2020) – “Fertility Rate”. Published online at Retrieved from: ‘‘ [Online Resource]

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