We are often intimidated with tales of impending catastrophes that will erase the history of mankind. A global nuclear war, a pandemic, climate change, an asteroid collision - this is not a complete list of threats that, in theory, can lead to the decline of our civilization.
However, serious research gives a paradoxical result: even if something similar happens in reality, people will not only survive, but also multiply.
Doomsday scenarios
The idea of the inevitability of the end of the world came from religious concepts, but was initially supported by scientists. Moreover, if religions described a global change in the world after the onset of the Day of Judgment, then science, based on observation of nature, immediately proceeded from the fact that the extinction of mankind would not have a decisive influence on the further development of the Universe. Scientists said: yes, perhaps someday we will disappear, but the stars will continue to shine, giving life to new worlds and creatures.
At the turn of the 19th and 20th centuries, scientific eschatology (this is the name of the entire set of numerous theories about the end of the world) discussed two main threats: the degeneration of humanity as a result of technological progress and the fall of a giant comet.
In addition, famous science fiction writers of the time, Albert Robida and HG Wells, described the devastating destruction that weapons of mass destruction used in the European war would inflict. By the way, Wells was one of the first to use the term "atomic bomb".
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And yet that era was marked by social optimism - even the most gloomy forecasts boiled down to the fact that some part of humanity will be able to survive the catastrophe and lay the foundation for the formation of a more perfect society.
The situation in the assessment of threats changed when real atomic weapons appeared. Some physicists believed that even one bomb explosion could destroy our planet with all its inhabitants. For example, there were fears that a self-sustaining thermonuclear reaction of nitrogen combustion would start, which in a few minutes would cover the entire atmosphere of the Earth. However, calculations showed that such a development of events is extremely unlikely, so the atomic bomb was still tested, and later used against Hiroshima and Nagasaki.
Later, a similar problem was discussed in connection with the tests of thermonuclear bombs - theoretical models appeared showing that when a certain power is reached, an explosion will cause detonation of the oceans due to the deuterium contained in the water.
These models, too, turned out to be in the end erroneous, and they were replaced by the concept of a nuclear winter, built on the basis of research on possible climate changes after the massive use of atomic weapons. Today the concept is contested because of the uncertainty that it fully takes into account all natural factors.
Doomsday argument
In the 1980s, attempts were made to justify eschatology mathematically. Using the theory of probability and estimates of the number of people who lived before, astrophysicist Brandon Carter put forward the "End of the World Theorem", which is also called the "Doomsday Argument".
The meaning of the theorem is that in terms of probability we are most likely in the middle of the chronological scale of human existence.
If we accept this assumption, then, knowing the dynamics of population growth, we can use a special formula to calculate how long humanity will live and how many it will reach by the notorious Day of Judgment.
One of the predictions prepared by the philosopher John Leslie based on the theorem is as follows. If we assume that 60 billion people have lived on Earth until now, then we can say that the total number of people will not exceed 1.2 trillion.
Assuming further that the world's population stabilizes at 10 billion people, and the average life expectancy is 80 years, we get the result: it will take another 9,120 years for the remaining billions of people to be born, and then something is likely to happen that will destroy our species.
However, more arbitrary values can be substituted into the formula, and then the life of mankind increases. For example, the cosmologist Richard Gott, who discovered the theorem independently of other authors, received a different period of 7.8 million years, which is quite enough for civilization to go beyond the mother planet and settle it in the Galaxy, and in this case the formula loses its meaning.
The considerations of the supporters of the doomsday theorem look speculative, because they rely on statistical measurements, and the mind also differs in that it often violates statistical laws.
On the other hand, he is also quite capable of inventing and implementing technology that will literally devour the world. For example, a lot has recently been written about the danger of the uncontrolled spread of "gray mucus" - microscopic robots with the ability to reproduce: futurologists believe that if they ever appear, they will rapidly process into their copies all terrestrial organic matter, including humans.
Will to live
However, not all forecasts are equally pessimistic. In October 2014, scientists Corey Bradshaw and Barry Brook published the results of their simulation, in which they considered nine scenarios for the development of civilization, including catastrophic ones.
In particular, they used scenarios of a worldwide pandemic, a global thermonuclear war and a sharp decline in the birth rate due to targeted social policies. Imagine their surprise when it turned out that even a war is not capable of dramatically thinning out humanity and somehow reducing the rate of demographic growth.
It is noteworthy that even if in the near future the whole planet adopts the policy of "one family - one child", as in China, by 2100 about 10 billion people will live on the planet. In this regard, the authors of the study are concerned about only one thing - in this case, will civilization be able to resist the final destruction of the terrestrial ecosystem and will it not exhaust all available resources?
There is an answer here too. Today we are seeing significant growth in the field of energy saving technologies. Economical household appliances are being produced, cars and even airplanes are switching to electric motors, and electricity itself is increasingly being extracted from renewable sources, that is, from sunlight, wind and sea waves.
In fact, we are on the verge of a new technical revolution, after which individual households will be able to produce energy on their own and share it with each other as needed. This state of affairs, if it prevails in the world, will significantly reduce the pressure on the ecosystem and create a new economy focused on meeting the basic needs of everyone.
If, nevertheless, some catastrophe occurs, then, as the experience of previous centuries shows, progress will go even faster, because the peoples of the Earth will face the question of survival, and not of momentary gain.
Bottleneck
A good illustration of how resilient humanity is to shocks is the "bottleneck effect" - a reduction in the gene pool of a population due to unfavorable conditions, clearly observed in wildlife (for example, on a population of cheetahs). It is known that the gene pool of mankind is depleted. Consequently, in some periods of our history, we passed through the "bottleneck" of evolution.
According to the latest research by geneticists, humans have been on the brink of extinction twice. About 1.2 million years ago, the number of our direct ancestors decreased to 26 thousand people, and about 70 thousand years ago, to 2 thousand. And at the same time, our ancestors, although they were in more severe conditions, managed to survive, survive, create a society, settle all over the planet and even take the first step into outer space. So are we and our children dumber than them?
Anton PERVUSHIN