This article is via WeChat public account “ Planet Science Review ” reproduced with permission from the author: Yun Wu ghost town, design: with Chen, Zheng Borong, editor: Xie Yu Han. Planet Science Review, a brand of Planet Research Institute, science, exploration, curiosity. Picture from: IC photo
In 1992, the late American comedian George Carlin spoke out in a 8-minute talk show about the remnant of the remnant: The earth has a history of 4.5 billion years … Earth is good It ’s just… It ’s just humans who are going to finish.
The late American comedian George Carlin and his famous comment on “Protecting the Earth” | Source of the basemap@mintpressnews.com
In recent years, due to dissatisfaction with a series of actions such as the US withdrawal from the Paris Agreement, many environmentalists have issued quite sharp criticisms, and some even have no practical value at all, just slogans for show. However, it is not rude to come and go, and many netizens with excellent memory have found the talk show 28 years ago as a tool to counter some of the more radical environmentalists.
Greta Thunberg, who appeared on the homepage of Time magazine | Swedish youth environmental activist Greta Tumberg is one of the more radical environmentalists in contemporary times. Picture source @Greta Thunberg’s social media homepage screenshot
George Carlin ’s conclusion may seem classic, but it actually confuses many subjects.Learning concepts is really good as a piece of music in exchange for happiness, and it cannot be used as a scientific principle.
Today is the 51st Earth Day. On such a day, let ’s put aside the talk show of professional comedians. Let ’s take a scientific look at what protects the earth. Protecting the earth is not only protecting human beings, because it is not just us who are going to die.
What is the earth?
Few people ask such a seemingly boring question: What is the earth? As the saying goes, the sound is loud and the elephant is invisible. It is precisely because all the stories of life, death, old age, death and death of people and red dust happen on the earth. Instead, they do not know the true face of Lushan and are only in this mountain. They rarely think about such big questions as “what is the earth”.
However, this seemingly “philosophical” problem that everyone understands has many unknown scientific connotations behind it.
Rocky Earth
Is the earth a huge rock? If we go back to the days when the earth was born, we might say so. At the beginning of the formation, the earth had no life, no ocean, or even soil-the difference between soil and rock weathering is rich in organic matter and living organisms. At this time, the earth is also star dust that just gathered, countless rocks and dust, and small ice cubes and metal particles .
Asteroids and Comets in the Solar System | From top to bottom, they are the asteroid dragon palace 900 meters in diameter (Ryugu) , the shooting height is 6km, it was once shattered and shattered, and then the fragments re-aggregated into stars; the longest up to 4.1km of Chulyumov-Gerasimenko comet span class = “text-remarks” label = “Remarks”> (67P) , the shooting height is 285km, which is composed of rocks, dust and water ice. Images of some small stars in the contemporary solar system may give people a visual impression of the tiny stars that formed the earth. Picture source @ JAXA 、 NASA
But in later years, the earth became more than just rocks. The gravitational force causes the stardust to shrink, rub, and release heat, and the radioactive elements release energy inside the earth. The surface melted into a sea of magma.
Primary Earth and Protoplanetary Theia impact hypothetical map The fragments of the Earth and Theia collide to form the Moon, which has become the current mainstream view to explain the causes of the Moon. Picture source@Giphy.com
In a hot environment, the earth is gradually divided into crust, mantle and core . Those forbiddenThe volatile components trapped in the rock are also released, gathering into a dense atmosphere. When the magma sea began to cool, the atmosphere also cooled down, and for the first time raindrops fell on this large dry rock.
The formation of rain, as if a switch was pressed, a world of thousands and thousands would never start to flow.
Floating Earth
The earliest was about 4.4 billion years ago, the ocean appeared [1 ~ 4] , the surface of the earth began There are different colors. Since then, even though the sea and the plateau have been scattered, the ocean has always been the ocean of constant metabolism.
Imaginary Map of the Ancient Pseudo-Earth | At the end of the Ancient Pseudo-Earth (4.6 billion to 4 billion years ago), the ocean may have appeared on Earth. Picture source @ Simone Marchi / swri.org
The ocean not only creates the water cycle, it is also the largest heat regulator on the surface of the earth, which profoundly affects the flow of water and the atmosphere. They are constantly flowing on the rocky earth and become an important force for shaping surface rocks.
Glaciers and rivers flow on the ground, all rivers return to the sea, and gravel is sand.
Glaciers and Rivers | Picture Source @ VCG
Aeolian sand and floating dust “flow” in the sky, sharpening the rocks and covering the sky.
wind sand and floating dust | Picture Source @ VCG
These flowing landscapes are volatile under the influence of temperature and humidity, turning the rocky earth into a flowing earth. There are solidified flowing scenery everywhere: sedimentary rocks.
Ancient sedimentary rocks and modern gullies sediments complement each other well || They are all flowing landscapes on the earth. Picture source @ VCG
But in the water, a bigger change is brewing: great life.
Living Earth
There is still no answer to the exact birth time and birth location of life, but this does not affect people looking for the relationship between life and the earth. South Africa ’s Witwatersrand Basin has the world ’s largest gold deposit, where people found 2.7 billion years old pyrite deposits [5 ~ 8] .
Golden yellow pyrite gravel | The rounded gravel is commonly known as pebbles, it is the product of rivers breaking and grinding rocks. The golden component in the picture is pyrite broken and rounded by running water. Picture source @ 321gold.com, see literature [6]
These golden pebbles are broken pyrite brought by rivers from the mountains. The erosion of the perennial rounded off its edges and angles [7 ~ 8] . In modern times, pyrite (ingredient FeS2) in humid and oxygen-rich rivers will soon be oxidized to black or red products , Cannot be saved as it is. But On 2.7 billion years ago, the earth ’s oxygen content was extremely low , and there was no oxygen in the river water, which made this kind of extremely special “pyrite pebble” travel through time and uncover that distant A little veil of the times.
Maybe there was an era when golden pyrite once covered the land . They are either piled up in the river channel, or scattered on the desolate land, or caressed by the waves on the beach.
Papakolea Green Beach in Hawaii | The surrounding fresh basalt and tuffs contain a large amount of green peridot crystals, which were washed by the waves into round sand grains and piled up in green beach. However, olivines are unstable in an oxidizing environment, and they will soon (geologically significant) be transformed into other products, similar to pyrite. Picture source @ VCG
But creatures changed the environment of the earth , ending this golden touch.
A group of phytoplankton that accidentally started photosynthesis began to change history about 2.4 billion years ago. They and their descendants absorb carbon dioxide to release oxygen. Such biological activities have created an oxygen-rich earth, permanently changing the atmosphere and hydrosphere-historically known as “ Great oxidation event ” [1] .
Sketch of the timeline of the Great Oxidation Event | The Great Oxidation event occurred about 2.4 billion years ago and permanently changed the earth ’s atmosphere and oceans. Picture source @ uwaterloo.ca
Biological activities produce oxygen, and the earth ’s environment changes, and then “ feedback ” to the biosphere or even the lithosphere, killing a large number of early organisms that can’t stand oxygen, and ending the golden pyrite pebbles Scenes everywhere on land have also caused a large amount of ferrous ions to be oxidized and precipitated, forming the most important iron deposit in the history of the earth- striped iron ore [1] , changed the appearance of the earth ’s lithosphere.
Band-shaped iron-bearing construction (BIF) | This is a type of iron ore co-created by living beings and the earth. The black band is the iron oxide interlayer. Picture source @ Prof. Dr. Michael Bau / Jacobs University Bremen
Similar examples are everywhere in the evolutionary history of the earth, where creatures change the environment and eventually change the environment. After billions of years of long evolution, biology and the earth have long been integrated, affecting each other . It is hard to imagine what would happen to the earth today if this mutation of photosynthesis did not appear in the beginning.
Microorganisms in hot spring pools | In the hot spring pools of Yellowstone National Park in the United States, there are many high temperature resistant microbes that use sulfur in water as energy Source, no photosynthesis occurs. These microorganisms gather on the rock wall to form a sticky “microbial mat / microbial mat”-the slippery feel of rocks in water. I believe many people have experienced it. This may be the most life form in the anaerobic earth. . Picture source @ VCG
The world we live in begins to look like a living creature —although it does not have a sense of freedom. The breathing, survival and reproduction of each species are affecting a small environment on this planet. And the accumulation of countless small environments constitutes the overall environment of the planet, which in turnIt acts on the organism itself, provides pressure for the evolution of the organism to create natural selection, and enables the organism to continue to change.
From the barren rocky earth, to the ever-changing water and atmosphere flowing earth, to the only living earth in the solar system that nurtures life, the evolving wheel rolls forward, and no one knows where it will go, especially when it is alive In addition to the evolution of the earth itself, human activities are superimposed.
Anthropocene
The idea of living earth, that is, the concept of “biology and earth interact”, deeply influenced some scientists in the 1970s and gave birth to a “strong-looking” Gaia Earth hypothesis << / strong> (Gaia Hypothsis) . This is a hypothesis system that pays special attention to the interaction between organisms and the earth. Many concepts have been integrated into contemporary earth system science, but it describes biology + earth as a “ super organism” and “biology tends to regulate the environment The idea of reaching a stable state to adapt to one ’s own survival was widely criticized, so he always walked outside the mainstream academic thoughts [9 ~ 13] .
The author of the Gaia Earth Hypothesis James Lovelock | Although the “Gaia Earth Hypothesis” is scientifically controversial, it is widely popular in popular culture Welcome, and some of its scientific connotations have also been recognized. Picture source @Screenshot from aeon.co, literature [14]
However, The contemporary earth is controlled by an extremely large superconsciousness, which is human consciousness . When we inject human consciousness into the idea of a living earth, things seem to become interesting:Every human individual is consciously or unconsciously consuming the environment. When an individual’s consciously or unconsciously multiplies by 7.8 billion people, it is like a huge invisible consciousness, manipulating the earth to continue to advance in a certain direction.
Yes, the times have changed for adults, welcome to the earth of anthropology.
Anthropocene
The influence of humans on this planet is so great that many scholars in different fields have begun to advocate the definition of the era we live in as a new geological era: Cenozoic—Quaternary—Anthropocene < / strong> to replace the Holocene (11,700 years ago to present) currently in use.
March 12, 2015 Cover of Nature Magazine | “Anthropocene” is a hot topic in recent years and has attracted the attention of multidisciplinary researchers. Its initial date was set in the 1950s, but it has not yet become a term officially recognized by the International Stratigraphic Commission. Picture source @ Naturemagazine
The blaze of industrial fire that has been burning for more than two hundred years has given humans the first time to have the ability to change the earth on a large scale according to their own ideas, or various “feedbacks” triggered by their activities > Change the planet. As the power to dominate the Anthropocene planet, these activities have even been written into the geological record and become part of the history of the planet.
On July 16, 1945, the first atomic bomb exploded in New Mexico, USA, not only produced a terrible mushroom cloud, but also caused radioactive dust to go with the wind and gradually settled around the world. Since thenFrom 2016 until 2016, a total of more than 2,000 nuclear warheads were detonated at or near the surface, and a large amount of radioactive dust accumulated in the formations around the world, becoming a “strong and thin red line” with significantly higher radioactivity. —— This is the most “magnificent” mark left by mankind to this planet, which will remain in the rock formation for at least billions of years.
Nuclear Explosion | The Licorne nuclear test conducted on July 3, 1970 in the French Polynesia Islands. Picture source@planetdeadly.com
In addition to this, the concrete, glass, plastic and other hard-to-degrade materials we produce will also become “ technical fossils ” buried in the sediments, demonstrating human industrial manufacturing capabilities.
Plastic bottles overgrown with barnacles | Even if they float in the high-temperature and high-salt ocean, the plastic sheets can last for a long time and even become attached to barnacle animals Bed. When they finally sink to the bottom of the sea, they spilled over the entire sea and became artificial trash on the seabed. Picture source @ VCG
Fertilizers, pesticides, organic pollutants, and enriched metal elements will remain in the soil, the bottom of the lake or the bottom of the sea, and become “ geochemical fossils “, demonstrating human technological capabilities.
As for those underground structures, mines, oil drilling, mines, tailings pits and other places that have damaged natural strata, they still retain traces of industrial transformation and become “ information fossils ” Human transformation of the rocky earth.
Ordered slag is often buried in the slag, they retain traces of artificial fracture, which is completely different from the surrounding rocks and natural mud, Save the “Here Mined” information. Picture source @ VCG
In addition to these tangible changes, there is also an intangible human heritage, that is, pollutants and greenhouse gases emitted into water and the atmosphere.
Best era vs worst era
From the perspective of human survival, having a huge ability to transform nature helps to acquire more resources and open up the frontier of human survival. It seems that For humans, “this is the best era.”
But in terms of ability to influence nature, “this is also the worst era” . The rocky earth is the accumulation of interstellar material in 4.6 billion years. Humans are so small in front of it. So far, they have only completed drilling at a maximum vertical depth of 12,262 meters. For the land crust with an average thickness of 35 km, it is completely impossible to destroy.
Kola Super Deep Drilling | The Kola Super Deep Drilling SG-3 with a vertical depth of 12262 meters is still the deepest drilling in mankind. The project was started in 1970, stopped in 1995, and the wellsite was abandoned after 2005. Picture source @wikipedia
But for the flowing earth composed of the atmosphere and the hydrosphere, the emission of various pollutants and greenhouse gases overwhelms the atmosphere and water, and the changes caused by mankind have long been too big to ignore.
Taking greenhouse gas as an example, in 1992, when George Carlin conducted the talk show, the global greenhouse gas carbon dioxide content was 356ppm, which has now risen to 416ppm, an increase of 16.8%; methane content is 1735.4 ppb, has now risen to 1874.7ppb, an increase of 8% [17] .
Related environmental data for the Hawaiian region of the North Pacific as of 2018 | Atmospheric carbon dioxide, seawater carbon dioxide partial pressure, and seawater acidity are gradually increasing. Picture source @NOAA
Physically, greenhouse gases such as carbon dioxide can trap large amounts of surface heat radiation, and the resulting radiative forcing is the main reason for contemporary global warming [18]. In just 28 years, we have created many new problems in a generation. These environmental changes have begun to significantly affect ecosystems and human society [18 ~ 19] .
For nature, the habitat of animals and plants changes rapidly (heating, drought, flooding, fire, seawater acidification, seawater hypoxia, etc.) some of the creatures that are difficult to migrate in time can not escape the disaster of the top [18 ~ 19] . Take corals that ca n’t migrate as an example. The continuous warming of seawater gradually causes corals to gradually expel symbiotic algae from the body, losing color and losing nutrients produced by algae It will soon die from starvation, a phenomenon called coral bleaching .
Coral bleaching | Coral loses symbiotic algae, turns white, and soon dies of hunger. Picture source @ USGS
According to statistics, from 2016 to 2017 alone, about 93% of corals in the Great Barrier Reef in eastern Australia experienced varying degrees of bleaching. From 2014 to 2017, 70% of the world’s corals were threatened by bleaching. If the seawater is allowed to keep the current rate of temperature increase unchanged, by the end of this century, the shallow water corals in the ocean may die out [20 ~ 24] .
Severe coral bleaching in Australia ’s Great Barrier Reef in recent years | 20Between March and November 2016, the Great Barrier Reef in Australia was hit by a powerful heat wave, and about half of the corals eventually died in the northern part of the highest temperature (9.5 ° to 14.5 ° latitude). The southern area was less damaged. Figure b is DHW (Degree Heating Weeks, the water temperature in a week exceeds the local average maximum water temperature in summer a few degrees). At present, the corals in these places have not been restored. It is estimated that it may take 10-15 years to fully recover to the previous state. Source @ 文 [20]
For humans, animals and insects that accelerate the pace of migration have an impact on human habitats, and even accelerate the spread of diseases , for example, the incidence of dengue fever in southern China has increased in recent years due to the increase in the number of mosquitoes < span class = "text-remarks" label = "Remarks"> [25] ; The frequent occurrence of natural disasters and the further rise of sea level also increase the risk of climate refugees and social unrest; The adverse impact of the industry is far greater than the favorable impact [19, 26 ~ 27] , which affects human society from a more secretive perspective, and may even be triggered by hunger War; the melting of glaciers will exacerbate regional water shortages and cause social instability.
An epitaph for Ok Glacier ｜ In August 2019, Iceland ’s Ok Glacier was disqualified due to serious melting This is an epitaph written by the Icelanders for Ok Glacier, and it stays where it once stood. Cartography @ 陈 随 / 明星 科学 评
“This is the best era and the worst era.”
If we continue to cherish the traditional concept of “conquering nature”, this is undoubtedly the best era. But from the perspective of “sustainable development”, this is also the “worst time.”
With industrial capabilities, humans haveHaving become the power that dominates the flowing earth and the living earth, only human beings have the ability to make changes in the present.
Protect the earth related to you and me
How bad is this era? We need to choose a appropriate time scale to look at it scientifically.
The earth has a history of 4.6 billion years, and various changes last for varying lengths of time. Just as the time scale of the climate change caused by the plate movement is from 100 million to tens of millions of years, but the scale of the alternation of cold and warm caused by the change of the four seasons is one year, when using different scales to look at the world, controls the environmental changes The factors obviously vary.
Long observation scale does not help people to correctly understand the severity of contemporary environmental problems.
The age of dinosaurs is much warmer than it is today, but it has nothing to do with you or me. Because on the scale of 100 million years of observation , the causes of climate change are super macro factors such as plate drift and ocean closure, which have already melted into the background of our time-we are in a In the cooling trend of more than 55 million years, this is related to the collision of the Indian plate and the Eurasian plate.
Cenozoic that is getting colder at different scales of observation ｜ On the scale of tens of millions and millions of years, the global temperature of the Cenozoic has long been cold; When you look at it, you can find the obvious periodicity. Picture source @ 文 [28] (above), NASA (below)
The birth of human ancestors more than 3 million years ago was warmer than modern times, but this has nothing to do with you or me. Because on the observation scale in millions of years , the uplift of the plateau and the uplift of the mountains are more significant climate control factors, and the Qinghai-Tibet Plateau started a new round of rapid uplift about 3.5 million years ago Up to about 4000 meters so far, it has significantly affected the global monsoon [29 ~ 30] .
Temperature changes in the last 150,000 years and the latest 11,000 years | On the scale of 150,000 years, the contemporary era is a stable high period after rapid warming; On a scale of 11,000 years, the contemporary era is in a state of overall stability and slow cooling (regardless of contemporary global warming). Picture source @NCDC (above), literature [31] (below)
The Northumbria period about 8000 years ago (8200 ~ 4200 years ago) than todayThe temperature is 3 ~ 4 degrees Celsius, the estuary of the Yangtze River is still near Zhenjiang, and the sea level of the East China Sea is 2 ~ 3 meters higher than contemporary [32 ~ 34] . But it has nothing to do with us, because it was in a period of high temperature after the end of a 100,000-year climate cycle. On the scale of observation from 10,000 to 100,000 years , the change of the earth ’s rotation axis will cause the change of the received solar radiation intensity, thus changing the earth ’s climate, which is called Milankovich Cycling , they also blend into the background of our time.
Different cycles of Milankovitch cycle and glacial period corresponding map | Milankovitch cycle has several different levels of cycle, the cycle is about 95,000 The eccentricity cycle of -125,000 years is the most obvious for the climate control factors in recent hundreds of thousands of years, and the other cycles are superimposed. Picture source @wikipedia
These concepts of different time scales, like Russian matryoshka, have small cycles in large cycles and smaller cycles in small cycles, superimposed into an intricate system, which is also the biggest feature of the earth system < span class = "text-remarks" label = "Remarks"> [1] .
Russian setBaby | The earth system has a variety of periods on different time scales, which are layered together like a Russian matryoshka. Picture source @ VCG
When we are discussing “climate warming”, it means that on the 100-year time scale since the Industrial Revolution , the world ’s temperature is rising rapidly; if we stand at 100,000 On the annual scale , the modern earth is at the end of the last 100,000-year cycle, the rapid warming has ended and is about to start a period of tens of thousands of years of cooling period; if it stands at 50 million years of On the time scale, the trend of long-term cooling since the Cenozoic is very obvious, and it seems that it will not be a problem for another ten million years.
Based on different observation scales, the temperature change curves of geological history period || The scale of observation scales in different eras in this picture is different, from the billion-year scale to the millennium scale, we Very different conclusions can be drawn. Picture source @ VCG
Not to mention, the state of cold and warm is never the point, The speed of change of cold and warm is . Whether for humans or all creatures, too fast environmental changes will cause great survival pressure. However, the rapid rate of global warming since the Industrial Revolution is not only unprecedented in human history, but even in the geological history period, it is very rare. Even in the Paleocene-Eocene extreme heat event 56 million years ago, the (PETM) event, the heating rate is only 1.0 degrees Celsius per thousand years [35] .
But in the contemporary era, people are facing a temperature increase rate and a greenhouse gas accumulation rate that is ten times or even tens of times faster than the PETM period.rks “label =” Remarks “> [35 ~ 38] is how to control the temperature rise within 2 degrees Celsius in the next 80 years. If it is not controlled, it is entirely possible to heat up in 2100 by 5.5 (or higher) around 140 degrees Celsius, facing the global ecosystem change in PETM period after 140 years [38] .
In the era of PETM, some marine plankton and benthic organisms became extinct. If a similar situation occurs again in the anthropocene world, what impact will it have on the ocean and human society? This is still unknown.
Paleogene “Paleocene-Eocene Extreme Thermal Event” schematic diagram | This event occurred in the Paleogene 0.55-0.56 billion years ago In the early period of the epoch, the temperature of the atmosphere and the ocean increased rapidly and then fell back, and the rapid decomposition of combustible ice was one of the possible reasons. 图 源 @ 文学 [37]
The rate of environmental change on the contemporary earth exceeds the imagination that geological records can provide. I am afraid that only only catastrophic events such as super volcanic eruptions and large asteroid impacts can be compared to the impact humans are having on the planet.
There is no trace to follow, it is for trouble.
Looking at the near future with a scale of one or two hundred years , if people do n’t really take the courage to break the wrists of the strong men to do something, let the contemporary carbon emission situation continue to develop, not only human life It will become a mess in the future, and the situation of all creatures will also change drastically-in a sense, it will get worse.
Which future will humans choose? ｜ The RCP path is a future heating scenario simulated based on different carbon emissions. The RCP2.6 path to vigorously reduce emissions to achieve negative emissions is the most ideal expectation. The global warming at the end of this century will not exceed 2.3 ° C; The worst expectation is that the global average temperature at the end of this century may rise by 3.2-5.4 ° C. Cement also produces carbon dioxide emissions during production and normal use, which is an important source of carbon emissions other than fossil fuels. Picture source @ 文 [39].
In the past 4.5 billion years, the earth has experienced many environmental changes, but this has nothing to do with you or me. In the hundreds of millions of years since, it has been turned upside down, and the overly distant changes have nothing to do with you or me. Naturally it will erase everything it can erase, and find a place where it will survive in the ups and downs.
Only the present and the future, only the next 100 and 200 years, are related to you and me, to future generations, and to all living creatures growing under the same blue sky.
In the face of the short-term environmental impact caused by human activities, they and we are both victims. The current living earth is the biggest victim.
So, Does the earth need human protection?
Of course it needs, and humans also have this ability. What is lacking is the courage to act, the solidarity and justice between developed and undeveloped countries, and a gradual and effective scientific method.
Protecting the earth is not only protecting ourselves | there are also mountains and rivers, and souls. Cartography @ 郑伯容 / Planet Science Review
Protecting the present earth is not only protecting the future of human beings, because it is not just us who are going to die, but also those animals and plants that are being affected by rapid environmental changes.
To protect the present earth, not to protect the huge rock ball in this universe, but to protect the hydrosphere, atmosphere, and biosphere (and other surface circles Layer) ;
Protecting the present earth is not only protecting the living beings living with us on the earth, but also protecting the anthropogenic earth that can be felt now. It is protecting every stream, every breath, every blooming flower, And every living creature in the distance.
Do you want to “even if I die after the flood”, or do you have to make more scientific, rational, and responsible choices for the well-being of future generations and the survival of all creatures? Do you have an answer to this multiple choice question?
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