Ecology: Biology of Interaction. 6.04. Can Earth’s Population Size Be Limited?
As a consequence of Earth’s overpopulation, many proposals have been put forward to reduce global population. At first glance this seems straightforward, but practical implementation of large-scale demographic regulation has repeatedly proven extremely difficult.
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6.03. Demographic transition
D. Shabanov, M. Kravchenko. Ecology: Biology of Interaction Chapter 6. Human Ecology and Conservation
6.05. Food security
6.04. Can the Earth's population be limited? There is no return to caves: there are too many of us. Jerzy Lec The consequence of Earth's overpopulation has been various proposals to reduce its population. It might seem that this is not such a difficult task: first, to figure out how many people the Earth can "withstand" without harm to itself, and then to agree, limit births, and reduce the population to the desired level... "How many people is the Earth designed for? It turns out that biologists can answer this somewhat strange question quite definitively. The fact is that the biosphere is arranged quite "sensibly." It strictly adheres to the relationship 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 supporting role. Humans, along with domestic animals, have disrupted this relationship, exceeding their share in the biosphere. But the biosphere is a self-regulating system, and it strives to return the human population to the permissible level. And it is twenty-five times lower than the current one – two hundred million – for the entire planet. The extinction of species needed by humans, the non-inclusion of pollutants we produce in the biosphere's cycles, and the decline in the productivity of ecosystems valuable to us – all this can be understood as a feedback effect, the action of a biosphere mechanism that seeks to limit human growth. As long as humans are armed with fossil energy sources, they have the ability to resist pressure. But when these sources are depleted, only solar energy can ensure the long-term stable existence of humans. However, realistic estimates show that even with the fullest use of solar energy (partly directly, in power plants, partly by processing their products into fuel by plants and bacteria, and partly in the form of harvests consumed by humans and domestic animals), only about one percent of the biosphere's power can be used without harm to the biosphere. This is ten times less than the current energy consumption of humanity. Based on solar energy, only about 500 million people can exist indefinitely, consuming as much energy per capita as is currently consumed on average worldwide" (V.R. Dolnik, 1990). Since this estimate was made, the human population has grown, as has the level of per capita energy consumption. Now, to reach the desired level, our species must reduce its numbers not tenfold, but significantly more! However, is the current energy consumption really the norm for humanity? According to some models, the carrying capacity of the environment for humanity is about 8 billion, which is a completely acceptable estimate and not much lower than the population at which the growth of our species may stabilize. How to determine which model is more realistic? If it becomes clear that a reduction in the Earth's population is necessary, how will this reduction occur? "How long will it take humanity to reduce its population tenfold without threatening to undermine the achieved level of civilization after it realizes the necessity of this reduction? The answer is unequivocal – the minimum time is the average human lifespan (~70 years in developed countries). For this, it is necessary to reduce the birth rate 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 the introduction of pension provision only for disabled elderly people. In this case, the gross domestic product per capita may remain unchanged or even increase, as the time for technological change is approximately an order of magnitude less than the lifespan of one generation. A twofold reduction in population over one generation occurs when switching to one-child births, which all civilized countries are already close to" (A.M. Makaryeva, V.G. Gorshkov, 2007). "Recipes" like the latter have only one drawback – they are entirely speculative. Not once in the entire history of humanity and in the entire history of attempts to manage birth rates has it been possible to carry out even significantly less large-scale restructuring of demographic processes. To date, the most successful experience in population control has been accumulated in China, the most populous country, where this experience is implemented under the strict control of the ruling Communist Party of China. The success of this program lies in a certain reduction in population growth rates, not in a reduction in population size. The consequence of this will be that after some time, China will cede the primacy of the most populous country in the world to India; India's population reduction program (which included, among other things, forced sterilization of people – with the use of army units to suppress protests) failed. Perhaps a shortage of resources and hunger will lead to a gradual decrease in the human population to the level indicated by specialists? Such a scenario is also impossible. With a shortage of resources, people left without means of subsistence make efforts to save themselves and redistribute resources. The struggle for scarce resources leads to their even sharper depletion. It is not to be expected that humanity, which has reached titanic, unprecedented sizes for the Earth's biosphere, will sharply reduce its numbers on its own. Apparently, current humanity will either survive while maintaining its numbers, which will continue to grow for several decades, and only then stabilize or begin to slowly decline, or human civilization will disappear from the face of the Earth completely or almost completely... Additional materials: Column: Dies irae
6.03. Demographic transition
D. Shabanov, M. Kravchenko. Ecology: Biology of Interaction Chapter 6. Human Ecology and Conservation
6.05. Food security