On January 20, 2022, Science and Technology Daily reported that the Earth we live on has experienced five global mass extinction events since the birth of life. One of the fifth global extinctions we know best, which caused the dinosaurs to completely disappear from the earth, and humans have since taken the stage. However, many scientists are now calling through research that a sixth global mass extinction is taking place, and that the humans who dominate the planet will be the objects of extinction. This is not alarmist, so who is behind this mass extinction? How should humanity respond?
The first five global extinctions
The five mass extinctions that have occurred on Earth have their own characteristics and have had far-reaching effects.
The first global mass extinction, 439 million years ago, at the end of the Ordovician period, wiped out 86 percent of life on Earth, and scientists believe the two major events that led to this extinction were glaciation and sea level decline. There are also theories that the Earth is covered with so many plants that they remove too much carbon dioxide from the air.
The second global mass extinction, 365 million years ago, in the late Devonian period, saw about 75 percent of the species disappear, and even the trilobites that remained from the Ordovician extinction nearly died out in this extinction. Scientists believe that the deep roots of giant land plants release nutrients into the ocean, eutrophication leads to the proliferation of algae, and the lack of oxygen in the ocean leads to the death of organisms; in addition, volcanic ash not only reduces the temperature of the earth, but also kills land spiders and scorpion-like organisms.
The third global mass extinction, 250 million years ago, at the end of the Permian, is also considered a very serious one in history, as nearly 96% of species have disappeared, including ancient coral species. The mass extinction was caused by a huge volcanic eruption, which filled the air with carbon dioxide, breeding a large number of bacteria, bacteria releasing methane, warming the earth, and turning the oceans sour, but after experiencing this extinction, new species such as snails and crabs were born as never before.
The fourth global mass extinction, in the late Triassic Period, 200 million years ago, lost a large number of species, as was the case with other mass extinctions. Scientists blame the extinction on asteroid collisions, climate change and other reasons.
The fifth global mass extinction was in the late Cretaceous period 65 million years ago, and this extinction was also the most well-known, resulting in the complete disappearance of the dinosaurs that once controlled the earth, and now people can only study the appearance and life characteristics of previous dinosaurs from the surviving dinosaur fossils. But dinosaurs aren't the only species that went extinct, with as many as 75 percent of species dying in this extinction.
Many animals and plants perished in this extinction, but mammals and birds were fortunate enough to survive and continually adapt and evolve under the new natural environment, resulting in many of the animals we see today.
Scientists believe that the mass extinction is due to a major asteroid impact on the earth, a huge space rock hit the earth and send debris into the air, completely changing the climate of the entire earth, which led to the extinction of the earth's organisms.
In addition, some people speculate that the climate change caused by the movement of the Earth's plates, as well as volcanic eruptions and ocean tides.
Five global extinctions have caused the disappearance of large-scale organisms for a variety of reasons, from climate change to volcanic eruptions, asteroid impacts on Earth, and even evidence of accelerated geological evolution by microbes. But mass extinctions have also brought about the evolution of biological species on Earth. In order to adapt to the changed natural environment and fill the ecological deficit caused by the extinction of the species in time, the few species that survived the mass extinction accelerated their evolution and rapidly multiplied the varieties, resulting in many completely new species.
Behind the scenes
The first five global extinctions have had an irreversible impact on the planet, so whether the sixth global mass extinction has been quietly carried out today is what many scientists think. The journal Biology Review recently published a new study showing that Earth's sixth global mass extinction has begun, and the main cause of this change is not volcanic eruptions or asteroids hitting the Earth, but a warming climate, which is actually mainly caused by humans.
Since the birth of life on Earth, a total of 5 billion species of organisms have evolved, including various phyla, but there are only 10 million species left on Earth today, and some of these remaining organisms are still going extinct. Moreover, the increasingly wide range of human activities, especially the environmental pollution caused by industrial production and climate change, has led to the extinction rate of species 10 to 100 times faster than normal.
Human beings, especially after entering the industrial age, the rapid development of industry has promoted the progress of human beings, but at the same time it has also caused great damage to the natural environment, and human beings' desire to conquer nature has been expanding, and they have more and more destroyed nature to satisfy their ambitions. The three wastes of industry, the expansion of the scope of human life, and the use of nuclear weapons and atomic bombs in war have caused the direct death of many species, and climate warming is gradually increasing.
In the midst of the third global mass extinction, studies have shown that an increase in greenhouse gases in the atmosphere has led to a continuous warming of the earth, and as the oceans warm, the metabolism of life living in the oceans accelerates, and they need more oxygen, but warmer oceans with less oxygen in warm seas not only push organisms away from the tropics, but also force most organisms that are difficult to adapt to the environment.
This is very similar to today's warming, and Payne, a professor of geological sciences at the University of Washington, believes that if the current state of carbon dioxide emissions is followed, by 2100, the upper warming of the oceans will be close to 20% of the warming of the third global mass extinction, and closer to 35% to 50% by 2300. Such a judgment emphasizes that warming caused by human activities will lead to the same mass extinction of organisms as in the Permian.
Therefore, the judgment of the sixth mass extinction is not empty, and its impact is also huge, and the German branch of the World Wide Fund for Nature recently pointed out that more than 1 million species will go extinct in the next 10 years. According to Deutsche Welle, a study released by the German chapter of the World Wide Fund for Nature (WWF) in Germany indicates that about 142,500 species of plants and animals have been listed on the IUCN Red List of Threatened Species. This shows the large number and speed of species extinction on the earth.
For the Earth, the sixth global mass extinction is happening, but for human beings, this time will be a long time, and there is no need to worry too much in the short term, but in the long run, we must start to act from now on to live in peace with the Earth. Human beings are currently the masters of the earth, but if they let their own actions go, they cannot always be the masters of the earth, human beings are not as powerful as imagined, and many times they are very small in the face of the challenges of nature. Therefore, in the face of the sixth mass extinction that is quietly taking place, human beings need to use their wisdom to find the best of both worlds in the time that remains.
Resources
（1）Stanford Earth Matters magazine—What caused Earth's biggest mass extinction?—HANNAH HICKEY—December 06, 2018
（2）WorldAtlas Logo—Timeline Of Mass Extinction Events On Earth—Amber Pariona—March 5 2018
（3）ThoughtCo—The 5 Major Mass Extinctions—Heather Scoville—January 08, 2020
Author: XiangYi Proofreader: Plum