This article describes the natural disasters that humanity must overcome to avoid extinction. It introduces the factors that threaten human survival, emphasizes the importance of science and technology to overcome them, and discusses how advances in science and technology are directly related to human survival.

Natural laws and human survival

In the natural world, it is natural for species to be born and die. Since the first life appeared on Earth 3.8 billion years ago, countless species have been born and died. The reasons for extinction are varied. They may have been wiped out by predators or unable to adapt to changing habitat conditions. It could be a natural disaster like an asteroid impact or a genetic problem like a mutation. The point is, no matter how thriving a species is, it will eventually disappear. It’s a law of nature.
However, a species has emerged on Earth that can defy these laws. Humans evolved from apes about 1 million years ago. They had an “intelligence” that other life forms lacked, which allowed them to develop science and technology, which saved them from many extinction risks. They invented tools to overcome physical limitations, rose to the top of the food chain and escaped the threat of predators, and created clothing, housing, and irrigation systems that allowed them to adapt to all regions of the world. Today, our science and technology continues to advance rapidly, and advances in science and technology are increasing our chances of survival.
But it’s still too early to conclude that we’re completely immune to extinction. There are still catastrophes awaiting humanity that are incomparable to the crises we have faced so far. These catastrophes will shake the very essence of human life and push us to the brink of extinction. If humanity is to overcome them and survive, it will have to achieve a level of scientific and technological power that can prevent them. In the following, we’ll take a look at the catastrophes that threaten humanity’s survival, and what science and technology will be needed to overcome them.

The extinction of men, 120,000 years from now

In order to maintain the species, organisms need to produce offspring that look like themselves. In this process, the genes of the parents are replicated and passed on to the offspring. However, the process of gene duplication is not perfect, and mutations occur with a certain probability, resulting in a gradual loss of genetic information. In humans, autosomes come in pairs, so even if one chromosome is damaged, it can still make up for it by exchanging some of its genetic information with the opposite chromosome. The problem arises with sex chromosomes. Women have XX and men have XY sex chromosomes, but in men, the Y chromosome doesn’t have a pair to exchange genetic information with. Therefore, mutations on the Y chromosome don’t get repaired and continue to accumulate. If this process continues, at some point the Y chromosome will no longer function, and humans who inherit an XY chromosome will be born female. At this point, the human race can no longer reproduce and becomes extinct. Calculating the cumulative rate of mutation on the Y chromosome, we estimate that it will take about 120,000 years. If humans have not developed the technology to control mutations on the Y chromosome by then, or if they have not found a way to reproduce without the Y chromosome, they will become extinct.

Plant extinction, 100 million years later

At the beginning of the geologic era, the atmosphere was inhospitable to animals because the main components of the atmosphere were methane, ammonia, and carbon dioxide. However, during the evolution of life, plants appeared that absorbed carbon dioxide and released oxygen. As plants flourished, the concentration of carbon dioxide in the atmosphere became less and less. As a result, Earth now has the right concentration of carbon dioxide and oxygen for life to thrive, and Earth’s biosphere is at its peak.
However, this thriving of plants is not permanent. The trend of decreasing atmospheric carbon dioxide will continue in the future, and at some point, there will no longer be enough carbon dioxide left to support photosynthesis in plants. This will lead to the extinction of most of today’s multicellular plants as early as about 100 million years from now. The loss of plants will cause a cascade of ecosystem collapse, and multicellular organisms, including humans, will inevitably disappear from Earth’s biosphere. To prevent plant extinction, humans need to keep the Earth’s atmospheric composition constant. To do this, we need the technology to intervene in the global cycling of matter and artificially control all of its processes, so that the composition of the Earth’s materials can be continually tweaked to prevent it from becoming a planet unsuitable for life.

Loss of oceans and atmosphere, 700 million years later

The reason planets can have atmospheres is because their gravity holds gas molecules to their surfaces. Over time, however, gas molecules escape into outer space, and at some point, the planet’s atmosphere disappears. Based on the current rate of atmospheric loss and future conditions on Earth, it is predicted that Earth will lose its atmosphere in about 700 million years. As the atmosphere evaporates and atmospheric pressure decreases, the evaporation of water vapor from the oceans will also accelerate, leading to the loss of the oceans at the same time as the atmosphere. When the oceans disappear, the heat flow inside the Earth will stop, and the plates will stop moving. The Earth would become a dead star. It’s difficult for humans to control the escape of these planetary-scale gas molecules, so we need to constantly supply the planet with water and oxygen. Many comets in the outer solar system are rich in water, methane, oxygen, and other resources. If we can get a steady supply of these gases to Earth, we might be able to prevent the loss of our atmosphere and oceans.

The Sun’s demise, 6 billion years later

The Sun’s lifespan is also finite. As main-sequence stars similar in size to the Sun approach the end of their lives, they become more and more massive, becoming red giants. In about 3.5 billion years, the Sun’s expansion will cause Earth’s surface temperature to reach more than 100 degrees Celsius, making it no longer habitable. After 5 billion years, the Sun expands to Earth’s orbit and swallows the planet. In this sequence, humanity is forced to move further and further out of Earth’s orbit to survive. If a comet with a diameter of about 100 kilometers repeatedly hits the Earth, the kinetic energy of the comet is transferred to the Earth and the Earth’s orbit is stretched out. Repeating this process over and over again would move Earth’s orbit to where Mars is today, where it would be safe from the Sun, which would become a red giant in 5 billion years.
But don’t get too comfortable. After becoming a red giant, the Sun will continue to burn until 6 billion years from now, when it will use up all of its hydrogen and explode, becoming a white dwarf. During this explosion, everything in the solar system will be blown away. Humanity will meet its end with the sun unless we have the ability to migrate to another solar system before this moment arrives. However, if we find a habitable planet in another solar system before then and have enough time, resources, and technology to move humanity there, we may be able to survive once again.

Conclusion

These are some of the catastrophes that humanity will have to overcome to avoid extinction. In order to survive these catastrophes, our science and technology must advance. If the main purpose of an organism’s existence is the survival of its species, then humans must develop science and technology in order to keep the human species alive. Therefore, humanity should encourage and invest a lot of resources in the development of science and technology. Science and technology should not be limited by political logic, economics, etc. and should be prioritized over other values. We must not forget that science and technology are directly related to the survival of humanity.