If you think living longer will further increase ‘overpopulation’ – read this!
Surely all of you are excited about the benefits, anti-aging interventions could have on our health and lifespan. However, one thought has probably also crossed your mind:
If we make people live longer, won’t that contribute to overpopulation?
The short answer is No. Increasing health and lifespan of people won’t accelerate our inevitable doom. In fact, it will most likely delay it. Here is why.
Before the 1800s, European parents were used to have 4–8 children. However, due to the poor standards of living, only 1 or 2 of those children would reach adulthood. This meant the population only grew at a slow rate (Figure 1). Thanks to the industrial revolution and the improvements it brought to everyday life, there was an explosion in population starting in the 1800s. Better and cheaper food supplies, increase hygiene and fundamental discoveries in medicine meant that more people were reaching adulthood and therefore population growth exploded (Figure 1).
There is no population explosion problem.
Of course, ‘overpopulation’ would have been a real problem if growth rates would have stayed the same, however, the rate of population growth has been slowing since the 1960s, and has fallen below replacement levels in half of the world. But what about the other half? That’s where population is exploding, right? Well, actually, no. The UN Population Division’s world fertility patterns show that, worldwide, fertility per woman has fallen from 4.7 babies in 1970–75 to 2.6 in 2005–10. As “Peoplequake: Mass Migration, Ageing Nations and the Coming Population Crash” author Fred Pearce puts it: “Today’s women have half as many babies as their mothers … That is not just in the rich world. It is the global average today.”
According to Demographers, they think earth’s carrying capacity is 11–12 billion people. We are currently at 7.3 billion people now. According to Malthusianism, the earth has finite resources and an increase in population will lead to us using up all the resources. However, unlike bacteria human’s carrying capacity comes less from environmental restrictions and more from our own economic behavior. The birth rate has been falling rapidly, from 37.2 births between 1950–55 to 19.4 births per 1000 between 2010–2015 and you can’t blame resources for it because the gross world product increase 19 times over the same period from 4 trillion to 77 trillion. In Europe each couple only has 1.6 children which is not even enough to replace the existing population. So, we have not been growing exponentially since 1960 — it has been only linear. We are heading linearly towards a flat curve. We are past the point of maximum growth.
There will be no population explosion problem in the future.
One of the most common objections against aging research has been the fear of catastrophic population consequences. In the “worst-case scenario” where hypothetically the mystery of aging has been solved and there will be no deaths going forward our intuition suggests that immortal people will reproduce and eventually lead to an infinite number of people on earth. However, the magic of calculus tells us otherwise.
To keep calculations simple, imagine a situation in the future where couples all over the world have decided to just have one child (which is a trend observed in most developed countries at present). This would mean that for every 1 generation, 0.5 is being added to the next generation and this would follow an infinite geometric series converging in the end to double the total immortal population (Figure 2)
In other words, a population of immortal reproducing organisms can grow indefinitely in time, but not necessarily indefinitely in size, because asymptotic growth is possible. Thus, even in the case of the most radical life extension scenario, population growth could be relatively slow and may not necessarily lead to overpopulation.
Now that it’s clear that the population is never going to be infinite, the real concerns should not be directed to the threat of overpopulation but instead on removing the obstacles to developing health- and lifespan-extending interventions, which would dramatically improve the quality of life.
