Ecology: Biology of Interaction. VI-08. Is It Possible to Limit the Earth’s Population?

Appendices: Curriculum. Questions. References. Personalities. Glossary. R Commands.

VI-8. Is It Possible to Limit the Earth’s Population?
There is no going back to caves: there are too many of us.
Jerzy Lec
The overpopulation of the Earth has given rise to various proposals to reduce its population. It may seem that this is not such a difficult task: first determine how many people the Earth can “support” without harm, and then agree to limit birth rates and reduce the population to the required level…
“How many people can the Earth accommodate? It turns out that biologists can answer this somewhat strange question quite specifically. The thing is that the biosphere is organised quite rationally. It strictly adheres to the dependence between the size of organisms that consume organic food and their numbers. Small organisms play the main role in the flows of matter and energy in the biosphere, while large ones play a supplementary role.
Humans, together with domestic animals, have violated this dependence by exceeding their share in the biosphere. But the biosphere is a self-regulating system and it tends to return the human population to the permissible level. And this level is twenty-five times lower than the current one — two hundred million — for the entire planet. Both the extinction of species necessary for humans, and the failure of our pollution to enter biospheric cycles, and the decline in the productivity of valuable ecosystems — all this can be understood as feedback, as the action of a biospheric mechanism seeking to limit human population growth.
As long as humans are equipped with fossil energy sources, they can resist this pressure. But when these sources are exhausted, only solar energy will be able to ensure indefinitely stable human existence. However, realistic estimates show that even with the fullest use of solar energy (partly directly in energy installations, partly through plants and bacteria converting their products into fuel, and partly in the form of crops eaten by humans and domestic animals), only about one percent of the biosphere’s capacity can be used without harming it. This is ten times less than current human energy consumption. On solar energy alone, only about 500 million people could exist indefinitely, consuming the same energy per capita as the current global average” (V.R. Dolnik, 1990).
Since this estimate was made, the world’s population has grown further, as has per capita energy consumption. Now, to reach the necessary level, our species would need to reduce its numbers not tenfold, but much more! But is current energy consumption truly the norm for humanity? According to some models, the carrying capacity of the environment for humanity is about 8 billion, which is a quite acceptable estimate and not far below the population at which our species’ growth might stabilise. How to determine which model is more realistic? If it becomes clear that a reduction of the Earth’s population is necessary, how would this reduction take place?
“How long would it take humanity to achieve a tenfold reduction in population without threatening the level of civilisation achieved, once it recognises the necessity of this reduction? The answer is clear: the minimum time is the average human lifespan (~70 years in developed countries). To achieve this, it is necessary to reduce birth rates to one child per ten women of reproductive age. This is entirely possible with the rapid expansion of the child-free community worldwide and the complete abolition of retirement age, with pension provision only for incapacitated elderly people. At the same time, gross domestic product per capita could remain unchanged or even increase, since the rate of technological change is approximately an order of magnitude faster than the lifespan of one generation. A twofold reduction in population within the lifetime of one generation occurs with the transition to single-child birth, which all civilised countries are already approaching” (A.M. Makaryeva, V.G. Gorshkov, 2007).
“Recipes” of the kind just described have only one flaw — they are entirely speculative. Not once in the entire history of humanity and all attempts to manage birth rates has it been possible to achieve even far less extensive transformations of demographic processes. To date, the most successful experience of limiting population growth has been accumulated in China, the country that was for a long time the most populous in the world. The slowing of population growth in China took place under the strict control of the ruling Communist Party. The success of this programme lay in some reduction in the rate of population growth, and not at all in a reduction of the population. As a result, China eventually ceded to India the status of the world’s most populous country; India’s population reduction programme (which also included forced sterilisation of people — with the use of military units to suppress protests) failed. China is now trying to overcome the negative consequences of declining birth rates and has begun to stimulate them.
Perhaps a lack of resources and famine will lead to a gradual reduction of humanity to the level indicated by specialists? Such a scenario is also impossible. When resources are scarce, people left without means of subsistence make efforts to save themselves and redistribute resources. The struggle for resources leads to their even more rapid depletion.
It is unrealistic to expect that humanity, having reached titanic proportions unprecedented in the Earth’s biosphere, will drastically reduce its own numbers. Apparently, either present-day humanity will be able to survive while maintaining a population that will continue to grow for several more decades and only then stabilise or begin to slowly decline, or human civilisation will disappear from the face of the Earth entirely or almost entirely…