I. INTERNAL DEMOGRAPHIC PROBLEM

Population load of children and the elderly

Human beings, as all other mammals as well as birds, have to spend much parental time and energy on bringing up the offspring, from birth to the reproductive age. Unlike, e.g., fish, mammals and birds cannot produce a great number of very small offspring that could be left for themselves, because very small animals (less than 1 g) cannot maintain high and constant body temperature essential for the survival of mammals and birds. Besides, an additional factor evolved that made the childhood of human beings exceptionally long, by several times exceeding the corresponding period in mammals of similar size. Human brain takes a very long time to develop as it has to absorb and process (i.e., to learn) large amounts of the cultural (non-genetic) information accumulated by previous generations. In the results, the period of parental and societal care of the young became several times longer in Homo sapiens compared to other mammals. This, together with the efforts to maintain the life of the eldery members of the population who are unable to provide for their living themselves, makes up the burden imposed on the working, functionable part of the population. Obviously, the population will not survive if this burden becomes unfeasible.

Irrespective of how it is defined numerically, the cumulative young and elderly burden is minimal in the stationary population. The very notion of burden refers to a growing or declining population. As is well-known from the demographic equations developed by Lotka (see Appendix 1), in a growing population the burden of the young grows exponentially, while the burden of the elderly exponentially shrinks and ultimately becomes negligible. In primitive human populations that existed under the natural conditions the amount of food secured by a working member of the population per unit time, was limited by the physiological power of the individual. This set a limit to the per capita number of offspring and, hence, to the intrinsic rate of the population growth. This had been the only limitation faced by human population during the entire pre-industrial era. The fact that our species (Homo sapiens) exists for more than a hundred thousand years unambiguously suggests that the pre-industrial human population had been perfectly self-consistent and had no problem coping with the burden imposed by either the young or the elderly.

In a shrinking population the burden of the young becomes small. In natural human populations the burden of the elderly does not increase even if they are shrinking. In natural human populations life expectancy (the mean number of years to death) after a certain age practically did not depend on age up to the biological age limit of Homo sapiens. (That is, after reaching maturity the probability of dying soon (e.g., next month) is rougly independent of age). Only a very small portion of the natural population survives to the biological age limit. These are the most healthy members of the population, who often retain the ability to work and do not impose any burden on other population members. On the contrary, in all natural populations the oldings are in charge of the accumulated cultural experience of the population and are valued high in the society (have a high social rank).

In the industrial era, in the rapidly growing human population the relative number of the elderly was very low. This made it possible to introduce the old-age pension, when people could (or were forced to) retire at a certain age irrespective of whether they were capable of working further or not. With the transition to a stationary population, the economic burden of retirement becomes increasingly noticeable with the decreasing age of retirement. The elementary solution of this problem lies in the increase of the retirement age or, more radically, in the abandonement of the age retirement system altogether, preserving pensions for only those people who are unable to work.

In the modern civilized societies of the developed countries the growing degree of automatization in all industrial spheres allows one to greatly reduce the number of working members of the population, theoretically -- down to zero. In such a highly technological society a negligible part of the population will be able to coordinate all industrial processes providing the rest of the population with everything necessary. People will be free from tedious, boring work and will spend time satisfying their true -- biological -- aspirations, with sport games, tourism, fishing, hunting, intellectual development etc. It should be stressed that in the natural environment all individuals of all biological species find themselves in a similar state. As testified by direct observations, natural species spend but a negligible part of their time budget on such essentials like feeding. "High technologies" for such a comfortable, happy existence of natural species are provided by the biosphere itself, in particular, by the photosynthesizing machinery of green plants. Man chose to leave this paradise and fell into the trap of technological progress, which goes hand in hand with population growth. Today there is an opportunity of returning to the paradise of normal life at a different, highly technological, level. This opportunity, however, can be realized if only our population harmonizes its relationships with the external environment, which, as shown below, is only possible at a substantial reduction of global population numbers.

To summarize, in reality the load of children and the eldery does not, by itself, pose any problem and cannot compromise the internally coherent existence of human population. In the preindustrial society the children load determined the limit of the intrinsic population growth. With the development of technologies population growth started to be determined by the rate of food production. So far this rate has been increasing very rapidly due to continuous extension of cultivated lands and technologically manipulated agricultural yields. In the result, the rate of global population growth reached its maximum -- it came close to the biological reproductive limit of the woman.

The state of our environment is determined not by the rate at which population numbers grow or fall, but by the current absolute number of people inhabiting the Earth. What is the magnitude of an environmentally tolerable human population? -- this is the essence of the second, external problem of demography that is discussed below. Here we only mention that prior to the industrial revolution, when global population was ten times lower than it is today, every generation enjoyed a stable and favorable environment that might change only very little over an individual lifetime. At those times no concerns were put forward regarding the state of the environment, because the environment remained stable and human-friendly.

Suppose the humanity have realized the necessity of global actions towards reducing population numbers. How long can it take to achieve a tenfold reduction of global population numbers without threatening the existent level of civilization development?

The answer is quite unambiguous, the minimum time is given by average human lifespan (~70 years in developed countries). Birth rate should be reduced to one child per ten women of reproductive age. This is possible via a world-wide increase of the number of child-free members of human population, with the system of old age retirement to be replaced by the system of poor health retirement. During this transition the per capita gross domestic product can remain unchanged or even increase, because the time of appearance of new, more advanced technologies is about one order of magnitude shorter than individual lifetime. A twofold reduction of population numbers occurs if one applies the one-family-one-child reproductive scheme, which many developed countries today come close to. More detailed estimates of the rate of population reduction at any birth rate changes can be obtained from the numeric analyses of Lotka's demographic equations (see Appendix 1).

 

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