The answer to "there is only one earth"

From the time it appeared on the earth, human beings were primary in biology. Compared with the ancient life that began to multiply on the earth 3 billion years ago, the history of human beings can only be traced back to 2 million years ago at most, and it looks quite young. Judging from the time span in which human beings are fortunate to exist on the earth, it seems that there is nothing to boast about compared with the150 million years when dinosaurs ruled the earth. However, some scientists have suggested that we should mark a new development period in the evolutionary history of the earth-"Anthropocene", because in this period, human beings have no less influence on the earth's environment than the activities of nature itself, and have deeply engraved their own marks in the evolution of the earth.

It can be said that human beings are the most advantageous creatures in the history of the earth. Corresponding to the improvement of the civilization of human society, this species is also accelerating to change the physical, chemical and biological characteristics of the planet where it lives.

Humans have turned forests into cultivated land and grasslands into pastures, and the rapidly expanding cities since the rise of the industrial revolution have become the most obvious landmarks on earth. Today, cities, farmland and pastures have occupied more than one third of the earth's land area. Accompanied by this, human beings have discharged a lot of waste while consuming excessive natural resources. Compared with other species, human beings not only enjoy a luxurious life, but also are never satisfied and always want to get more from nature. This uncontrolled demand and destruction of nature will eventually lead to the rapid growth of population and the continuous deterioration of the natural environment, which not only reduces the quality of life of itself, but also threatens the survival of other species. The 2004 Global Species Survey Report published by the International Union for Conservation of Natural Resources shows that there are more than 15000 species on the earth on the verge of extinction, and the rate of species extinction is 1000 times that of natural extinction, more than ever before. Scientists warn that life on earth is going through a mass extinction.

In fact, the mass extinction in the history of the earth is not an isolated case, and it has experienced five mass extinctions in the evolution of life on the earth. Every extinction is closely related to the drastic changes in the environment. For example, the recent fifth extinction was triggered by a small celestial body hitting the earth 65 million years ago. At that time, a celestial body almost the size of Mount Everest hit the shallow sea in the Gulf of Mexico, triggering a tsunami and igniting a global fire. The land is flooded, the forest is burned, and the smoke and dust remain all year round. Plants wither because they can't carry out photosynthesis, and animals starve to death because of lack of food. As a result, 75% species, including dinosaurs, bid farewell to the earth forever in this disaster.

It is worth noting that the first five mass extinctions were all natural disasters, and this time it was man-made: carbon dioxide emitted by human beings led to global warming, freon used by human beings led to ozone hole, chemicals released by human beings polluted rivers, lakes and oceans, human farming and grazing led to a sharp decrease in the area of forests and grasslands ... The drastic global climate change caused by human activities led to the extinction of a large number of animal and plant species.

One species actually controls the power of life and death of other species. If people who live on the earth with humans are conscious, what will they think? Will they look forward to an earth without human beings? In his new book The World Without Us, Dr. Allen Wieseman, a scientist from the University of Arizona, conducted an interesting thought experiment on how the earth will change after the disappearance of human beings. He thought for a moment, "When human beings become the past, what fate will those material civilizations we created face?" ? Will nature erase all traces? Is there anything that can be preserved forever? "In this thought experiment, there is no explanation for the sudden evaporation of human beings from the earth. It simply sets the premise of the sudden disappearance of human beings, and then deliberately describes what is most likely to happen on the earth after several years, decades, centuries or even hundreds of millions of years. Areas abandoned due to accidents, such as around the Chernobyl nuclear power plant; Those inaccessible areas for various reasons, such as the demilitarized zone at the junction of South Korea and North Korea, provide vivid reference for this thinking.

This is really a clever idea. Let's follow Dr. Wieseman's ideas and paint a picture of the earth after the disappearance of human beings.

Without human beings, most of the once beautiful and spectacular achievements of civilization will vanish. After 654.38+million years, only some bronze statues can remain basically the same. The only signal that can show that human civilization has existed for a long time is the signal of radio and television programs, which will always spread weakly and intermittently in space.

Without humans, nuclear power plants and nuclear weapons that are not maintained will eventually leak. Fortunately, for nature, the result of leakage is not as terrible as most people think, and wild animals don't care so much about nuclear radiation. One example is that in just over 20 years, plants and animals at the site of the Chernobyl nuclear disaster have flourished.

Without human beings, the ecological environment on the earth will gradually improve, man-made chemicals will slowly dissipate, and the oceans, rivers and air will become clean after tens of thousands of years, and nature will dominate the earth again, which is good news for most species. Greedy shotguns are gone, elephants are no longer slaughtered for ivory, tigers can safely take mountains as kings, and pregnant Tibetan antelopes can migrate safely ... only some animals that depend on human survival will suffer, such as rats, cockroaches, cows, dogs and other artificially selected animals. Areas where crops such as rice, wheat and corn are planted on a large scale, and even cities and villages are gradually returning to natural ecosystems, but at different speeds. Warm and humid areas will recover faster than cold and dry areas, and areas with rich species will recover faster than areas with single species. Two centuries later, all the places in the world suitable for plants will be covered with weeds, shrubs and forests again, all kinds of animals will flourish, vibrant ecosystems will spread all over the world, and the earth will return to a healthy state.

Although the earth without human beings will undergo great changes, it will also encounter disasters, just like the earth before human beings appeared. But obviously, the appearance of human beings makes the speed or acceleration of this change much higher than that of nature, making the earth's biosphere always in a state far from balance, and there is always the danger that the whole system will collapse because of human beings. Therefore, the depressing conclusion is logical: the earth seems better without human beings.

In fact, in the biological world, powerful human beings are really fragile. Once the existing ecosystem is destroyed, humans and animals will bear the brunt, while plants and microorganisms will not have much impact. For centuries, human arrogance has prevented it from facing up to life on earth and correctly understanding its connection with the world.

Today, some people's earth is real, but no one's earth is fictional. The exploration of the real world and the deduction of the imaginary world are based on the deep sense of human suffering. Thinking in two directions leads to the same focus: let human beings make new choices on the basis of understanding their relationship with nature.