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Why do some scientists think that human beings are in the sixth extinction?
What will the earth look like in 2020? First, let's talk about the global temperature change in 2020. Global warming has changed beyond recognition. Nowadays, global warming is becoming more and more serious. At the same time, under the influence of global warming, according to the data released by the European Climate Center, 2020 has become the hottest year in history, reaching the level of 20 16, which is hard for many people to believe, because the speed of global warming has exceeded expectations. So from the perspective of global warming, there will be more "chain effects".
Fires in Australia-forest fires in Australia, whether in Genesis or at the end of 2020, indicate that global warming is changing Australia's climate phenomenon. The Australian Climate Center also announced that creating new high temperature, high temperature and drought has become a frequent climate phenomenon in Australia, so Australia will definitely be a difficult region in the future. In forest fires, the mass death of living things is more serious. Judging from the published data, it has reached more than 3 billion, which is a catastrophe in the biosphere.
Locusts in East Africa-The impact of locusts in East Africa is fatal, and the scale of locusts in East Africa has reached a record high. In previous years, we have never seen such a powerful scene in 2020, which affected many food crops and aggravated the food crisis in East Africa. Wait a minute.
This is what we simply said happened in 2020, sea level rise, storms, floods and other problems, and a lot happened in 2020.
202 1 what will we face? We have said that 2020 is called "disaster" by many people, but the United Nations believes that a global disaster will break out in 20021year, and only some countries will be spared. This shows that 2020 is not a disaster at all, and 202 1 is more severe, mainly because the global hunger problem is more severe. The United Nations pointed out that in 20021year, people in more than a dozen countries will face famine and suffer the worst humanitarian crisis in 75 years.
At the same time, under the influence of epidemic and war, the total number of people who want to help will increase by 40% compared with 202 1 in 2020, so this is a disastrous problem. 202 1 will be the most difficult year for mankind. If some poor countries face these problems again, they may face a "disaster", which is 20265438+.
Humans are in the sixth mass extinction? Hawking's prophecy comes true? According to what we said above, scientists believe that it is true that human beings are in the sixth mass extinction. In fact, this possibility is still there. Of course, these changes are not only for human beings, but also for other life on earth. Therefore, the change of the earth is prompting the change of the whole life on the earth. Once humans change the earth to a "tipping point", it is basically impossible for humans to change the earth back to a state that does not affect life.
Hawking's prophecy comes true? According to the development of mankind today, Hawking's prediction may really come true. Hawking predicted before his death that if global warming continues to intensify, human beings will not be able to survive on the earth. Why do you say that? If human beings can't effectively curb the aggravation of global warming, the earth will be like Venus, the surface temperature will be as high as 460℃, and human beings will not be able to survive. So from the perspective of global warming, human beings are really making the earth more and more uninhabitable.
The climate change of the earth and other factors may be at the beginning of a new round of biological extinction on the earth, so today's life on the earth is like "ants on hot bricks" and can't get rid of the influence brought by the earth. Only humans can change the earth, protect it and make life on it last longer.
So, on the whole, Hawking's prediction of global warming is not endless. With the rising greenhouse gases emitted by human beings, all the chain effects will be stronger, then life on earth will probably be uninhabitable, and the sixth mass extinction will be staged ahead of schedule. This is a trend.
Twenty-eight years ago, Hawking and many scientists warned mankind that the earth would become a "fireball" in 2600. It was also twenty-eight years ago that 1700 top scientists in the world issued the warning of world scientists to mankind with a very serious attitude. They said that human activities are causing serious and irreversible damage to the earth, and if left unchecked, it will eventually make the earth uninhabitable.
One day 66 million years ago, dinosaurs lived an ordinary life at the end of Cretaceous. Suddenly, a huge red ball with a diameter of 10 km fell from the sky, and instantly crashed into a big pit with a width of 180 km on the ground, which broke the quiet daily life and ushered in a major reshuffle of the earth's ecological circle. The energy released by this impact is equivalent to 18. The asteroid was smashed into powder. For a long time, the earth was shrouded in smog, the air was covered with thick dust, and the temperature plummeted. The fifth mass extinction at the end of Cretaceous wiped out 75% of species, including dinosaurs, which was the closest to us.
In the past 500 million years, a planet on the earth has experienced five mass extinctions. At the end of Ordovician 450 million years ago, the direct cause was that Gondwana mainland entered the Antarctic region, which affected the global atmospheric circulation, led to global cooling, and the sea level dropped sharply, and about 27% of families and 57% of genera became extinct. In the late Devonian period, 380 million years ago, it was considered that the possible biological reason was that a large number of terrestrial plants multiplied, which led to the increase of oxygen content in the earth's atmosphere and the decrease of carbon dioxide, and entered the ice age, which mainly affected marine life, with about 19% families and 50% extinct; In the late Permian, that is, 250 million years ago, it was probably a large-scale volcanic eruption in Siberia, which led to the mass release of methane from combustible ice in the nearby shallow sea, forming a pan-continent, which changed the global atmospheric circulation and ocean current system. Many animals' orders or suborders were completely extinct, and about 57% of families and 83% of genera (including 53% of families, 84% of genera and 96% of oceans) were extinct in the Late Triassic 200 million years ago. It is generally believed that large-scale volcanic eruption caused the violent burning of combustible ice, and about 23% of families and 48% of genera were extinct (including 20% of marine families and 55%) And the end of the Cretaceous period 66 million years ago.
Every extinction, a large number of species disappear rapidly. In general, the extinction rate of a species is very low. Take mammals for example. There are about 5600 kinds of mammals living on the earth. According to the extinction rate calculated by scientists, only one mammal species will disappear every 700 years, but the truth is that one-third of all reef-building coral species, one-third of all freshwater mollusks, one-third of sharks and rays, and one-third of all mammal species. Just a few years ago, a report from Duke University claimed that the current extinction rate of species is more than 1000 times that of "the normal speed that nature should have". On the whole, the average extinction rate of vertebrates in the 20th century was 1 14 times of the normal extinction rate in nature. The United Nations Biodiversity Conference has estimated the extinction rate of species, and they think that there may be three species of extinction on the earth every hour.
I saw in a study in the Journal of the National Academy of Sciences that researchers from Stanford University and National Autonomous University of Mexico analyzed the quantitative trend of 29,400 species of vertebrates (birds, amphibians, mammals and reptiles), of which vertebrates 1.7% * * * 5 15, and the total number of individuals in the world was less than/kloc-. And half of them, two-thirds of mammals and amphibians, have less than 250 individuals. A detailed analysis of 177 species of mammals shows that 50% of the animal species that once shared the earth with us have completely disappeared, and billions of mammals, birds, reptiles and amphibians have become extinct, and they are still in another 65438+. In the past few years, these species have lost more than 40% of their habitats, and nearly half of them have lost more than 80% of their habitats from 1900 to 20 15. Only humans continue to expand the scope of life, and only humans continue to increase the number of races.
In fact, not only the change of natural environment will lead to the extinction of living things, but also human activities are very important reasons. Many scientists believe that the fuse of the sixth mass extinction was human beings. Great changes have taken place in the natural environment in the time visible to the naked eye. For example, global warming, which we often talk about now, has obviously caused the problem of sea level rise. Deforestation of forests, indiscriminate catching and killing of wild animals have destroyed the ecological environment of nature, wantonly reclaimed grasslands, caused land desertification, pumped groundwater uncontrollably, lowered the groundwater level, caused ground subsidence, abused mineral resources, scattered mercury, lead, cadmium, arsenic and various radioactive elements harmful to human health on the surface, and polluted the environment. Hazardous substances were extracted from deep strata and discharged at will without proper treatment. The industrial "three wastes" and pesticides harmful to human health are discharged into the atmosphere, rivers, lakes, oceans and soil without treatment or restriction, polluting and poisoning the environment, and some pollutants are enriched by crops and fish, eventually poisoning human beings. Some large-scale projects are not properly constructed, such as the construction of reservoir dams without paying attention to ecological problems, resulting in soil salinization and some fish extinction.
The director of Nanjing Paleontology Museum once said that since the industrial revolution, how much carbon dioxide has been emitted by human society, as well as a large number of chemical fertilizers used, nitrogen has to be extracted from the atmosphere to produce ammonia, which has caused obvious reduction reaction, making the nitrogen content in the atmosphere almost catch up with the "great oxidation" of the earth 2.4 billion years ago. Of course, as the leader of mass extinction, human beings are not helpless. Scientists mentioned many remedial measures, such as reducing meat consumption, reducing fertility rate, reducing energy consumption and using cleaner energy. I put it in a more popular way, that is, human beings must control population growth, reduce greenhouse gas emissions, and look for renewable energy. For other animals, we should also protect the habitats of various animals and plants, rebuild the ecosystem and curb environmental pollution.
I don't know when it started, but in fact, from a biological point of view, "man" is only one kind of animal kingdom-chordates-mammals-primates-hominids. We are not the masters of the earth, we are just a branch of the earth that breeds animals. Before humans learned to walk upright, they might just be a trivial species, just like
There have been five mass extinctions since the earth was recorded! Unfortunately, mankind is now in the sixth mass extinction. There are a lot of scientific data to prove this, but most people choose to pretend to turn a blind eye!
This is not an alarmist, the future of mankind is really not optimistic! As early as 28 years ago, 1700 of the world's top scientists issued the warning of world scientists to mankind, and three years ago, the United Nations 1500 of the world scientists issued the official warning of world scientists to mankind again. The core of the report is to warn people that human activities are causing irreversible serious damage to the earth. If left unchecked, it will eventually make the earth uninhabitable.
What concrete evidence shows that the sixth mass extinction is happening?
Let's talk about the ocean first! As we all know, coral is known as the "tropical rain forest at sea". As the cornerstone of marine ecology, it is an indispensable guarantee for breeding and maintaining marine life! The ocean has an ecological environment of14, which is independently formed around corals, and 25% of marine life depends on corals for survival and reproduction.
However, under the influence of human beings, 67% of the corals in the world have become albino, and the mortality rate of some species is as high as 90%, while the number of newborn corals has decreased by 89%. If the future is not improved, scientists predict that the corals in the world will disappear completely around 2070, and countless marine life species that depend on corals will disappear at the same time.
The most frightening thing is that scientists found the data of coral fossils 250 million years ago from the paleontological database and compared them with modern coral data. The results show that the abnormal reaction of corals today is very similar to the characteristics of corals in the last extinction period, and these same characteristics all point to the gradual deterioration of the earth's environment, which is no longer suitable for biological survival, leading to mass death of organisms!
The reality is the same, and now the creatures in the ocean are disappearing in a horrible proportion. Scientists have conducted long-term research on 88 sea areas. Due to the mass death of corals, compared with previous data, 50% of marine species have disappeared, which is more than twice that of terrestrial life.
This shocking number is increasing every day. If human beings don't control it, the consequences will be unimaginable!
Let's talk about land again! Twenty-eight years ago, scientists studied 29,400 species of terrestrial vertebrates and found that there are 5 15 species of vertebrates, and the total number of individuals in the world is less than 1000, which is extremely endangered. Two thirds of these 5 15 animals are mammals and amphibians, with less than 250 individuals. Results Scientists estimated that these species might be completely extinct in the next 20 years, but they didn't expect that there were 543 species of terrestrial vertebrates extinct so far, 30 more than scientists predicted.
In the past 100 years, 724 species of vertebrates disappeared from the earth. If we follow the evolution trend of life in the past two million years, this extinction will take at least 10000 years. In other words, human activities have increased the speed of species extinction by 100 times!
According to the World Red Book, 1 10 species of mammals and 139 species of birds disappeared from the earth in the 20th century. There are 593 species of birds, more than 400 species of mammals, 209 species of amphibians and reptiles and more than 20,000 species of higher plants in the world.
According to the report of Nature magazine, it is estimated that more than 654.38+billion species of terrestrial life will disappear from the earth within 50 years. Due to the influence of human activities, the rate of species extinction will increase to an average of one species per hour.
What is this concept? One species disappears every hour. How many species on earth can withstand such an extinction rate? It's terrible to think about it!
What caused the extinction of species on earth?
According to scientists' research, mass extinction is periodic, and it will only happen once in about 62,000 years. It is now exactly 65,000 years since the last extinction. In terms of time, we are in a high-risk stage of extinction.
In the past 540 million years, the earth has experienced five mass extinctions caused by geological or astronomical events. They occurred at the end of Ordovician about 443 million years ago (about 86% species were extinct); Late Devonian about 359 million years ago (about 75% species were extinct); At the end of Permian, about 25/kloc-0,000,000 years ago (about 96% species were extinct); About 200 million years ago at the end of Triassic (about 80% species extinction) and about 65 million years ago at the end of Cretaceous (about 76% species extinction). Dinosaurs were one of the victims of the last extinction.
The beginning of the sixth mass extinction was caused by human activities. Since the emergence of human beings, especially after the industrial revolution, due to the blind expansion of human beings, the life support system of the earth has been ruthlessly eroded by human beings, the ecological balance of many creatures has been destroyed by human beings, and the habitat has been continuously reduced. Although human development, the climate of the earth has become worse. And all kinds of human behaviors make the earth's environment vicious circle, and finally form a state unsuitable for biological survival, and the extinction of species begins unconsciously!
Ubiquitous damage to human life leads to air pollution, marine pollution and land pollution. Many pollutions cannot be eliminated naturally for a long time, and many damages are irreversible. The final result is a sharp change in the climate and environment, a sharp decline in biodiversity and the demise of ecosystems.
The frequent natural disasters, the spread of virus epidemic and the capriciousness of climate are all protests against the harm of the earth's environment to human beings. If human beings still go their own way and don't take warning, they will eventually suffer the consequences and cannot survive on the earth.
How to slow down the process of mass extinction?
Improving the earth's environment requires the joint efforts of all mankind. It's as big as shutting down polluting enterprises and stopping projects that affect the ecological environment, so small that people don't use plastic bags to buy food. Reduce harmful gas emissions, reduce sewage emissions, improve the recycling rate of waste, increase the application and development of clean energy, enhance people's awareness of environmental protection, and voluntarily participate in global environmental protection activities, and influence more people to participate in global environmental protection through their own actions.
Caring for the environment and protecting the earth is a persistent thing, but it needs constant persistence to improve, and human beings have a long way to go. For the earth, the sixth mass extinction is not a big deal. According to the past history, we can see that after each extinction, the surviving species will prosper again and become stronger.
It's just that for human beings, once the environment and species on which we live have changed greatly, we may not be able to survive in this world, so the reason why we want to protect the earth is not that the earth needs our protection, but that we want to protect ourselves.
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