Man lives in balance with other species in the world, which has certain limits. In this world it is impossible to achieve constant, once and for all established relationships — in all species have periods of growth and reduce population size.
Some species can dominate a certain time, and then become more dominant. If the species are close to each other in their "opportunities" that are "ups and downs" are usually not very significant.
If a predator depends on the particular type of production, he can not eat the whole population, because then he will be doomed to starvation.
If the changes represent graphically the two populations, it will be seen that they are constantly changing direction — up and down, like, for example, in this graph:
Figure 2. To illustrate the change in population predator-prey model is used trays — Voltaire. This graph reflects the situation where the change is not too significant
In fact, populations are often exposed to a much more substantial changes, as shown in the following example. At the beginning of the study period the number of baboons are 80 individuals, and the number of cheetahs — 40 individuals:
Figure 3. Lotka — Volterra used to demonstrate the situation, starting with the 80 baboons (green line) and 40 cheetahs (black line)
If species evolve in parallel, the natural balance between the populations remain roughly the same level. But if predators are suddenly finding another, better power supply (you can call it a source of energy, as the food supplies the body with energy), the population size can dramatically increase production.
For example, the yeast fungus is able to process sugar from grape juice, turning it into alcohol. The population of yeast on time increases and then decreases as the power supply disappears, and the fungus dies from alcohol. Or bacteria can multiply in the human body, if it finds necessary for self catering, and the body's defenses do not work quite effectively.
Often to illustrate this phenomenon gives an example of a deer population of the island of St. Matthew, which grew abundantly on the rocks lichen. Overgrown deer population began to eat the lichen at a higher rate than he grew up. At some point, the lichen is not left, and the curve of the deer population also fell sharply.
Figure 4. Changes in the number of herds of deer on the island of St. Matthew, according to a study by David Klein of the University of Alaska
An example of the reindeer is similar to the bold curves plot the "predator-prey". The deer ate the renewable power more quickly than he had time to play. On the island there were few other sources of food for animals, so some of them managed to survive, but still the population decline was very sharp.
In recent years, the number of people changed significantly:
Figure 5. These changes in the human population have been taken from the "Atlas of World History" Makevedi and Jones, 1978
The sharp increase in the number coincides with the extraction and use of fossil fuel and starts at the beginning of the 19th century. However, if we look at an even earlier time period, we can see that the growth observed over a very long period. Man has learned to use fire more than a million years ago. And since 75,000 BC, human population growth was fairly stable:
Figure 6. The growth of the human population as the acquisition of new sources of energy. Horizontal — the number of years up to the present time, Vertical — population size. From left to right: control over fire, agriculture, the development of global deposits, fossil fuels
The first significant population growth occurred when man learned to burn biomass and using the resulting fire to cook food, to bask, to improve the tools of stone and scare off predators.
All this has allowed our ancestors to colonize new areas of the globe, simultaneously wiping out many species of animals. Biologist and paleontologist Nils Eldredge believes that the first of the six periods of mass extinction of animals began when the first humans began to spread widely in different parts of the world about 100,000 years ago. The second phase began about 10,000 years ago, when mankind was engaged in farming. Even in these early stages of the energy used by humans has allowed them to increase their numbers by reducing the populations of prey animals.
In the period between 1 and 800 years BC there was a temporary increase in the number attenuation (Fig. 6). The period witnessed a lot of disasters in different parts of the planet, so the growth in one region counterbalanced by a decline in the other.
A man found a new resource for food — people have learned to clear the land of trees and irrigate it. But over time, the growth of population, available resources, to provide distributed. At about the same time, they began to run out. The land is no longer gave the former crop. Wages received by workers who fell and became more difficult to feed themselves. Beginning of the epidemic. Graphically, this period of decline can be depicted as follows:
Figure 7. Schedule of a typical long-term cycle of economic activity, built according to Peter Turkina and Sergey Nefedov: height — 100 + years of stagflation — 50-60 years, the crisis — 20-50 years, the transition period
So even in the period from 1 to 800 AD the population size was not stable. In fact, at this time in different places of the planet was observed either increase or decrease the number so that the overall number of people on the planet at this time, not much has changed.
Angus Maddison has analyzed the growth of GDP from 1 to 1000 century AD. He came to the conclusion that the GDP per capita declined slightly at the end of this period (453), compared with the beginning (476). According to his calculations, the state of the economy period from 1 to 800 AD was quite stable (with a large number of disasters), taking into account the lack of growth of GDP and per capita income.
In more recent periods of history we humans have managed to acquire new sources of energy (including peat moss, wind and water mills). There are well-equipped ships capable of carrying people to new lands to colonize and develop farming in new places, extract resources and transport them to their country.
Since 1800, due to increased production of fossil fuels, there was a sharp jump in the number of people and a significant increase in the level of his life.
Figure 8. World consumption of energy per person per year (blue — biofuels, red — coal, green — oil, lilac — natural gas, light blue — hydro-electricity, orange — nuclear)
Is it possible to achieve a stable state, and how?
Not a lot of options:
1. If you go back to the time when our ancestors had not yet learned to use fire, 100 — 200,000 of us could live in a warm climate, eating raw food and live approximately the same life as today live baboons or chimpanzees. In this case, the human population likely to be varied within certain limits.
Currently, human organs adapted to cooked food, and how they would react to a full syroyadenie not entirely clear. However, it is quite possible that living in areas with an abundance of soft food (berries, fish) would have been bearable. In addition, the climate must be warm so we do not freeze without coats. That these conditions were met, the population should be further reduced.
2. The absence of men in general, strictly speaking, can also be regarded as a stable state. But it is unlikely the prospect of such stability can arrange for one of us.
3. If we had not tried to globalization and stopped producing new supplies of energy, the situation could align local shocks such as those that took place from 1 to 800 AD It would also be a kind of steady state. However, in our global world problems can be easily moved from one part of the world to the other.
4. If we want to 7 billion people can continue to live, we need to ensure that their supply of energy even at the most basic level. If we assume that the survival of today's man needs the energy consumption at least at the level of 1820 (according to the data shown in Fig. 8), then each person should have at least 22 gigajoules. It's about 7 percent of today's consumption. That is, we would have to do without transport, electricity, water and sewage, so for us it would be a huge step backwards.
Even at the level of energy consumption in 1820, we still would have had to use fossil fuels in part, because we have too many, and one of biofuels would not be enough (marked in blue in Fig.
In addition, renewables, including modern hydroelectric and solar panels are also manufactured and transported using fossil fuels. Therefore, for the use of what we now regard as renewable sources, we must continue to produce fossil fuels.
In addition to all the above, we will have:
(A) reduce the growth in the number of people
(B) prevent the use of our available energy reserves (more than 22 designated gigajoules per person) and to achieve a fundamental change in lifestyle.
Often as measures to keep the growth of the world's population within a certain framework, proposed measures, such as raising the level of education among women, and more options for birth control. Unfortunately, these measures are also associated with the consumption of energy. In those circumstances, a question, a woman will have from morning to night work in the fields of education and she just did not have time.
Some cultures are able to keep the level of its population within certain limits by means not associated with the consumption of additional energy. In China, for example, strict birth control is mounted on top. In other countries, there are cultural and religious restrictions — delaying marriage, for example, or a long breast-feeding.
Even more difficult is to keep people from using the available sources of energy and change their way of life. Limit to 7 percent of the energy that a person has consumed so far, would mean losing almost everything to which he is accustomed.
There is a common misconception that the rejection of personal transportation can significantly affect the overall amount of energy consumed. In America, for example, gasoline accounts for about 44 percent of oil consumption. If we subtract this from the total amount of resource (including police cars, an ambulance and delivery of goods), we obtain savings of only 16 percent. In the rest of the world, where not everyone has a private car, the savings will be even less — an average of 10-12 percent.
Should we aspire to a stable state of the economy?
Now, apparently, we are moving to a demographic collapse, as the growth of the human population has long been not comparable with the growth of populations of other species. In addition, today we have many other restrictions, including the cost of oil production, the availability of fresh water and air pollution.
The only stable state, which would make sense, that if humanity could voluntarily withdraw its development back to a lower level — as an alternative to collapse. Unfortunately, it is difficult even to imagine how to do it. The only one in the history of a period of relative stability — between 1 and 800 years BC, when the growth of the human population in some regions of the place was counterbalanced by a decline in the other. Periods when the population growth in general was not, apparently, did not exist.
If, after the collapse of civilization will roll down to the lower level (but not to zero), it is likely to repeat the same pattern of development, again and again. Man will again increase and the number of population and consumption of resources available to him. This system is in our instincts and deal with it, it seems useless.
Whatever we do, sooner or later inevitably will crash, and mankind will roll down to the lower level of development.