An often heard criticism of the theory of shrinking ourselves to reach a sustainable human presence on Earth is that in the long run we’ll fill up the space we’ve created with more people and that, even at a much smaller size, we may be worse off. Although such criticism seems valid at first, it is very unlikely because we’ll shrink into a world of abundance. And contrary to what we might indeed have expected based on evolutionary biological rule, well-off people don’t have lots of children. Thus shrinking is more likely to lead to a stable population.
The historical demographic transition that underlays the phenomenon of developed nations having lower birth rates is traditionally divided into 4 stages. Stage 1 refers to a time when high birth and death rates more or less balance each other out. Stage 2 sees an enormous decline in death rates while birth rates remain high, leading to the population explosion we’ve seen over the past 50 years. In the third stage the population moves towards stability through a strong decline in birth rate, one of the most important reasons being that when we experience abundance we prefer to spend time doing other things than raising children. In the 4th stage population stability is reached. Some have suggested to include a 5th stage where populations will decline because of sub-replacement fertility. In theory this means that shrinking ourselves into abundance may ultimately lead the way to that other ‘big’ solution to an overpopulated world: downsizing the number of people on the planet.