In recent decades, we have increasingly heard about the problem of global warming and the greenhouse effect. Politicians, scientists, and journalists are arguing about what kind of climate change awaits us in the near future, what it will lead to, and how involved people themselves are in this. In this post we will try to understand the causes and consequences of the greenhouse effect.
Why do they talk about the greenhouse effect?
In the 19th century, scientists began to make regular observations of weather and climate across the planet. But in fact, using various methods, it is possible to establish how the temperature on the planet changed in the more distant past. And so, in the second half of the 20th century, scientists began to receive alarming data - the global temperature on our planet began to rise. And the closer to modern times, the stronger this growth.
Global temperature rise on graph
Of course, the climatic conditions on our planet have changed in the past. There have been global warmings and global cooling, but the current global warming has a number of features. Firstly, the available data indicate that over the past 1-2 thousand years the climate on the planet has not undergone drastic changes, with the exception of short-term anomalies. And secondly, there are many reasons to believe that the current warming is not natural climate change, but changes caused by human activity.
There is a lot of controversy on this matter. Soon after people started talking about the fact that humans are causing global warming, many skeptics appeared. They began to doubt that human activity could affect such global processes as the climate on the entire planet. However, there are good reasons to argue that humans are to blame for global warming. How did humans cause global warming?
In the 19th century, the world entered the industrial age. The emergence of factories and transport required a lot of fuel. People began to mine millions of tons of coal, oil and gas and burn them in ever increasing quantities. As a result, huge amounts of carbon dioxide and other gases causing the greenhouse effect began to enter the atmosphere.
And along with the increase in the content of these gases, global temperatures began to rise. But why does rising carbon dioxide concentration lead to warming? Let's try to figure it out.
What is the greenhouse effect?
People have long learned to grow vegetables in greenhouses, where they can harvest without waiting for the warm season. Why is it warm in a greenhouse in spring or even in winter? Of course, the greenhouse can be specially heated, but that’s not the only thing. Through the glass or film that covers the greenhouse, the sun's rays penetrate freely, heating the earth inside. The heated earth also emits radiation, giving off heat along with this radiation, but this radiation is not visible, but infrared. But for infrared radiation, glass or film are opaque and block it. Thus, it is more difficult to give heat to the greenhouse than to receive it, and as a result, the temperature inside the greenhouse is higher than in the open area.
A similar phenomenon is observed throughout our planet as a whole. The Earth is covered by an atmosphere that easily transmits solar radiation to the surface, but it does not transmit infrared radiation back into space from the heated earth's surface. And how much infrared radiation is blocked by the atmosphere depends on the content of greenhouse gases in it. The more greenhouse gases, and especially the main one - carbon dioxide, the more the atmosphere prevents the planet from cooling and the warmer the climate becomes.
What are the consequences of the greenhouse effect?
Of course, the point is not the greenhouse effect itself, but how strong it is. There has always been some amount of greenhouse gases in the atmosphere, and if they disappeared from the atmosphere completely, we would be in trouble. After all, with zero greenhouse effect, according to scientists’ calculations, the temperature on the planet would drop by 20-30 °C. The earth would freeze and be covered with glaciers almost to the equator. However, strengthening the greenhouse effect will not lead to anything good.
A change in global temperature of just a few degrees will lead (and, according to some observations, is already leading) to serious consequences. What are these consequences?
1) Global melting of glaciers and rising sea levels. Quite large reserves of ice are concentrated in the glaciers of Greenland and Antarctica. If this ice melts as a result of global warming, sea levels will rise. If all the ice melts, sea levels will rise by 65 meters. Is it a lot or a little? Quite a lot actually. A rise in sea level of 1 m is enough for Venice to drown, and for 6 m to drown St. Petersburg. When all glaciers melt, the Black Sea will connect with the Caspian Sea, and a significant part of the Volga region and Western Siberia will drown. Territories where more than a billion people live today will disappear under water, and the United States and China will lose 2/3 of their modern industrial potential.
Map of flooding of Europe due to melting glaciers
2) The weather will get worse. There is a general pattern - the higher the temperature, the more energy is spent on the movement of air masses, and the more unpredictable the weather becomes. Winds will become stronger, the number and scale of various natural disasters, such as thunderstorms, tornadoes and typhoons, will increase significantly, and temperature fluctuations will become more extreme.
3) Harm to the biosphere. Animals and plants are already suffering from human activity, but sudden climate changes can deal an even more powerful blow to the biosphere. Global climate change has led to mass extinctions in the past, and changes caused by the greenhouse effect are unlikely to be an exception. It is difficult for living organisms to adapt to sudden climate changes so that they can evolve and feel normal in new conditions; it usually takes hundreds of thousands or even millions of years. But changes in the biosphere will certainly affect humanity itself. For example, in recent years, scientists have already raised the alarm about the mass extinction of bees, and the main reason for this extinction is precisely global warming. It has been established that the increased temperature inside the hive in winter does not allow bees to go into full hibernation. They quickly burn fat reserves and become very weak by spring. If warming continues, in many regions of the Earth bees may disappear altogether, which will have the most disastrous consequences for agriculture.
Worst case scenario
The consequences described above are already enough to become concerned and begin to take measures to stop global warming. However, the uncontrolled growth of the greenhouse effect can trigger a truly murderous scenario that will lead to the guaranteed destruction of all life on our planet. How can this happen?
In the past, on our planet, the content of greenhouse gases in the atmosphere and global temperature varied within fairly wide limits. However, over long-term time periods, the processes that led to an increase in the greenhouse effect and its weakening compensated for each other. For example, if the CO₂ content in the atmosphere increased significantly, plants and other living organisms began to more actively absorb and process it. A long time ago, huge amounts of carbon dioxide captured by living organisms from the atmosphere turned into coal, oil, and chalk. But these processes took millions of years. Today, when people consume these natural resources, they return carbon dioxide to the atmosphere much faster, and the biosphere does not have time to process it. Moreover, due to his stupidity and greed, by polluting the world's oceans and cutting down forests, man destroys plants that absorb carbon dioxide and produce oxygen. According to some scientists, this could lead to the development of an irreversible greenhouse effect.
Today, the strengthening of the greenhouse effect is influenced by the growth of carbon dioxide, but there are other gases that can make this greenhouse effect even stronger, much stronger. These gases include methane and water vapor. As for methane, some of it enters the atmosphere during natural gas production, and livestock farming also contributes. But the main danger is the huge reserves of methane, which today are at the bottom of the oceans in the form of hydrates. As temperatures rise, hydrates may begin to decompose, a huge amount of methane will enter the atmosphere, and the greenhouse effect will sharply increase. The growth of the greenhouse effect will become irreversible. The stronger the greenhouse effect, the more methane and water vapor will enter the atmosphere, and the more of them enter the atmosphere, the stronger the greenhouse effect will become.
What all this can ultimately lead to is shown by the example of Venus. This planet is very close in size and mass to the Earth, and before spacecraft flew to this planet, many hoped that the conditions on it would be close to those on Earth. However, everything turned out to be completely different. On the surface of Venus there is terrible heat - 460 ° C. At this temperature, zinc, tin and lead melt. And the main reason for such extreme conditions on Venus is not that it is closer to the Sun, but the greenhouse effect. It is the greenhouse effect that increases the temperature on the surface of this planet by almost 500 degrees!
Venus and Earth
According to modern ideas, a “greenhouse explosion” occurred on Venus several hundred million years ago. At some point, the greenhouse effect became irreversible, all the water boiled and evaporated, and the surface temperature reached such high values (1200-1500 ° C) that the stones melted! Gradually, the evaporated water disintegrated into oxygen and hydrogen and evaporated into space, and Venus cooled, but even today this planet is one of the most unfavorable places for life in the solar system. The catastrophe that happened to Venus is not just a hypothesis of scientists; the fact that it really happened is confirmed by the young age of the surface of Venus, as well as the anomalously high ratio of deuterium to hydrogen in the Venusian atmosphere, which is hundreds of times higher than that on Earth.
What's the end result? It seems that humanity has no choice but to fight the greenhouse effect. And for this we need to change our predatory attitude towards nature, stop uncontrollably burning fossil fuels and cutting down forests.
Greenhouse gases
Greenhouse gases are gases that are believed to cause the global greenhouse effect.
The main greenhouse gases, in order of their estimated impact on the Earth's thermal balance, are water vapor, carbon dioxide, methane, ozone, halocarbons and nitrous oxide.
water vapor
Water vapor is the main natural greenhouse gas, responsible for more than 60% of the effect. Direct anthropogenic impact on this source is insignificant. At the same time, an increase in the Earth's temperature caused by other factors increases evaporation and the total concentration of water vapor in the atmosphere at almost constant relative humidity, which in turn increases the greenhouse effect. Thus, some positive feedback occurs.
Methane
A gigantic eruption of methane accumulated under the seabed 55 million years ago warmed the Earth by 7 degrees Celsius.
The same thing can happen now - this assumption was confirmed by researchers from NASA. Using computer simulations of ancient climates, they tried to better understand the role of methane in climate change. Currently, most research on the greenhouse effect focuses on the role of carbon dioxide in this effect, although the potential of methane to retain heat in the atmosphere is 20 times greater than that of carbon dioxide.
A variety of gas-powered household appliances are contributing to the increase in methane content in the atmosphere.
Over the past 200 years, methane in the atmosphere has more than doubled due to decomposition of organic matter in swamps and wet lowlands, as well as leaks from man-made objects such as gas pipelines, coal mines, increased irrigation and off-gassing from livestock. But there is another source of methane - decaying organic matter in ocean sediments, preserved frozen under the seabed.
Typically, low temperatures and high pressure keep methane under the ocean in a stable state, but this was not always the case. During periods of global warming, such as the late Paleocene Thermal Maximum, which occurred 55 million years ago and lasted for 100 thousand years, the movement of lithospheric plates, particularly in the Indian subcontinent, led to a drop in pressure on the seafloor and could cause a large release of methane. As the atmosphere and ocean began to warm, methane emissions could increase. Some scientists believe that current global warming could lead to the development of events according to the same scenario - if the ocean warms up significantly.
When methane enters the atmosphere, it reacts with oxygen and hydrogen molecules to create carbon dioxide and water vapor, each of which can cause the greenhouse effect. According to previous forecasts, all emitted methane will turn into carbon dioxide and water in about 10 years. If this is true, then increasing carbon dioxide concentrations will be the main cause of warming of the planet. However, attempts to confirm the reasoning with references to the past were unsuccessful - no traces of an increase in carbon dioxide concentration 55 million years ago were found.
The models used in the new study showed that when the level of methane in the atmosphere sharply increases, the content of oxygen and hydrogen reacting with methane in it decreases (until the reaction stops), and the remaining methane remains in the air for hundreds of years, itself becoming a cause of global warming. And these hundreds of years are enough to warm up the atmosphere, melt the ice in the oceans and change the entire climate system.
The main anthropogenic sources of methane are digestive fermentation in livestock, rice growing, and biomass burning (including deforestation). Recent studies have shown that a rapid increase in atmospheric methane concentrations occurred in the first millennium AD (presumably as a result of the expansion of agricultural and livestock production and forest burning). Between 1000 and 1700, methane concentrations fell by 40%, but began to rise again in recent centuries (presumably as a result of the expansion of arable land and pastures and the burning of forests, the use of wood for heating, increased numbers of livestock, sewage, and rice cultivation) . Some contribution to the supply of methane comes from leaks during the development of coal and natural gas deposits, as well as the emission of methane as part of biogas generated at waste disposal sites
Carbon dioxide
Sources of carbon dioxide in the Earth's atmosphere are volcanic emissions, vital activity of organisms, and human activity. Anthropogenic sources include the combustion of fossil fuels, the burning of biomass (including deforestation), and some industrial processes (for example, cement production). The main consumers of carbon dioxide are plants. Normally, the biocenosis absorbs approximately the same amount of carbon dioxide as it produces (including through biomass decay).
The influence of carbon dioxide on the intensity of the greenhouse effect.
Much still needs to be learned about the carbon cycle and the role of the world's oceans as a vast reservoir of carbon dioxide. As mentioned above, every year humanity adds 7 billion tons of carbon in the form of CO 2 to the existing 750 billion tons. But only about half of our emissions - 3 billion tons - remain in the air. This can be explained by the fact that most CO 2 is used by terrestrial and marine plants, buried in marine sediments, absorbed by seawater, or otherwise absorbed. Of this large portion of CO 2 (about 4 billion tons), the ocean absorbs about two billion tons of atmospheric carbon dioxide each year.
All this increases the number of unanswered questions: How exactly does sea water interact with atmospheric air, absorbing CO 2? How much more carbon can the seas absorb, and what level of global warming might affect their capacity? What is the capacity of the oceans to absorb and store heat trapped by climate change?
The role of clouds and suspended particles in air currents called aerosols is not easy to take into account when building a climate model. Clouds shade the earth's surface, leading to cooling, but depending on their height, density and other conditions, they can also trap heat reflected from the earth's surface, increasing the intensity of the greenhouse effect. The effect of aerosols is also interesting. Some of them modify water vapor, condensing it into small droplets that form clouds. These clouds are very dense and obscure the Earth's surface for weeks. That is, they block sunlight until they fall with precipitation.
The combined effect can be enormous: the 1991 eruption of Mount Pinatuba in the Philippines released a colossal volume of sulfates into the stratosphere, causing a worldwide drop in temperature that lasted two years.
Thus, our own pollution, mainly caused by burning sulfur-containing coal and oils, may temporarily offset the effects of global warming. Experts estimate that aerosols reduced the amount of warming by 20% during the 20th century. In general, temperatures have been rising since the 1940s, but have fallen since 1970. The aerosol effect may help explain the anomalous cooling in the middle of the last century.
In 2006, carbon dioxide emissions into the atmosphere amounted to 24 billion tons. A very active group of researchers argues against the idea that human activity is one of the causes of global warming. In her opinion, the main thing is the natural processes of climate change and increased solar activity. But, according to Klaus Hasselmann, head of the German Climatological Center in Hamburg, only 5% can be explained by natural causes, and the remaining 95% is a man-made factor caused by human activity.
Some scientists also do not connect the increase in CO 2 with an increase in temperature. Skeptics say that if rising temperatures are to be blamed on rising CO 2 emissions, temperatures must have risen during the post-war economic boom, when fossil fuels were burned in huge quantities. However, Jerry Mallman, director of the Geophysical Fluid Dynamics Laboratory, calculated that increased use of coal and oils rapidly increased the sulfur content in the atmosphere, causing cooling. After 1970, the thermal effect of the long life cycles of CO 2 and methane suppressed rapidly decaying aerosols, causing temperatures to rise. Thus, we can conclude that the influence of carbon dioxide on the intensity of the greenhouse effect is enormous and undeniable.
However, the increasing greenhouse effect may not be catastrophic. Indeed, high temperatures may be welcome where they are quite rare. Since 1900, the greatest warming has been observed from 40 to 70 0 northern latitude, including Russia, Europe, and the northern part of the United States, where industrial emissions of greenhouse gases began earliest. Most of the warming occurs at night, primarily due to increased cloud cover, which traps outgoing heat. As a result, the sowing season was extended by a week.
Moreover, the greenhouse effect may be good news for some farmers. High concentrations of CO 2 can have a positive effect on plants because plants use carbon dioxide during photosynthesis, converting it into living tissue. Therefore, more plants mean more absorption of CO 2 from the atmosphere, slowing down global warming.
This phenomenon was studied by American specialists. They decided to create a model of the world with double the amount of CO 2 in the air. To do this, they used fourteen-year-old pine forest in Northern California. The gas was pumped through pipes installed among the trees. Photosynthesis increased by 50-60%. But the effect soon became the opposite. The suffocating trees could not cope with such volumes of carbon dioxide. The advantage in the process of photosynthesis was lost. This is another example of how human manipulation leads to unexpected results.
But these small positive aspects of the greenhouse effect cannot be compared with the negative ones. Take, for example, the experiment with a pine forest, where the volume of CO 2 was doubled, and by the end of this century the concentration of CO 2 is predicted to quadruple. One can imagine how catastrophic the consequences could be for plants. And this, in turn, will increase the volume of CO 2, since the fewer plants, the greater the concentration of CO 2.
Consequences of the greenhouse effect
greenhouse effect gases climate
As temperatures rise, the evaporation of water from oceans, lakes, rivers, etc. will increase. Since warmer air can hold more water vapor, this creates a powerful feedback effect: the warmer it gets, the higher the water vapor content in the air, which in turn increases the greenhouse effect.
Human activity has little effect on the amount of water vapor in the atmosphere. But we emit other greenhouse gases, which makes the greenhouse effect more and more intense. Scientists believe that increasing CO 2 emissions, mostly from burning fossil fuels, explain at least about 60% of the Earth's warming since 1850. The concentration of carbon dioxide in the atmosphere is increasing by about 0.3% per year, and is now about 30% higher than before the industrial revolution. If we express this in absolute terms, then every year humanity adds approximately 7 billion tons. Despite the fact that this is a small part in relation to the total amount of carbon dioxide in the atmosphere - 750 billion tons, and even smaller compared to the amount of CO 2 contained in the World Ocean - approximately 35 trillion tons, it remains very significant. Reason: natural processes are in equilibrium, such a volume of CO 2 enters the atmosphere, which is removed from there. And human activity only adds CO 2.
Many people have probably noticed that winters have recently become not as cold and frosty as in the old days. And often on both the New Year and Christmas (both Catholic and Orthodox) it drizzles instead of the normal amount of snow. The culprit may well be a climatic phenomenon such as the greenhouse effect in the Earth's atmosphere, which is an increase in the surface temperature of our planet due to heating of the lower layers of the atmosphere through the accumulation of greenhouse gases. As a consequence of all this, gradual global warming occurs. This problem is not so new, but recently, with the development of technology, many new sources have appeared that feed the global greenhouse effect.
Causes of the greenhouse effect
The greenhouse effect occurs for the following reasons:
- The use of hot minerals such as coal, oil, and natural gas in industry, when they are burned, large amounts of carbon dioxide and other harmful chemicals are released into the atmosphere.
- Transport - a large number of both cars and trucks emitting exhaust gases also contribute to the greenhouse effect. True, the emergence of electric vehicles and the gradual transition to them can have a positive impact on the environment.
- Deforestation, because it is known that trees absorb carbon dioxide, and with each destroyed tree, the amount of this same carbon dioxide only grows (including right now our wooded Carpathians are no longer so wooded, no matter how sad).
- Forest fires are the same mechanism as during deforestation.
- Agrochemicals and some fertilizers also cause the greenhouse effect, since as a result of the evaporation of these fertilizers, nitrogen, which is one of the greenhouse gases, enters the atmosphere.
- The decomposition and combustion of garbage also contributes to the release of greenhouse gases, which increase the greenhouse effect.
- The increase in population on planet Earth is also an indirect reason associated with other reasons - more people, which means there will be more garbage from them, industry will work harder to satisfy all our not small needs, and so on.
The influence of the greenhouse effect on climate
Perhaps the main harm of the greenhouse effect is irreversible climate change, and as a result the negative impact from it: evaporation of seas in some parts of the Earth (for example, the disappearance of the Aral Sea) and, conversely, flooding in others.
What can cause flooding, and how is the greenhouse effect related? The fact is that due to rising temperatures in the atmosphere, glaciers in Antarctica and the Arctic are melting, thereby increasing the level of the world's oceans. All this leads to its gradual advance onto land, and the possible disappearance in the future of a number of islands in Oceania.
Territories that are little moistened by precipitation, due to the greenhouse effect, become very dry and practically uninhabitable. The loss of crops gives rise to hunger and a food crisis; we are now seeing this problem in a number of African countries, where drought is causing a real humanitarian catastrophe.
The impact of the greenhouse effect on human health
In addition to the negative impact on the climate, the greenhouse effect can also have an impact on our health. So in the summer, due to this, abnormal heat occurs more and more often, which from year to year increases the number of people with diseases of the cardiovascular system. Again, due to the heat, people’s blood pressure increases or, on the contrary, decreases, heart attacks and epilepsy attacks, fainting and heat strokes occur more often, and all these are the results of the greenhouse effect.
Benefits of the greenhouse effect
Is there any benefit from the greenhouse effect? A number of scientists believe that such a phenomenon as the greenhouse effect has always existed since the birth of the Earth, and its benefit as an “additional heating” of the planet is undeniable, because as a result of one of such heating, life itself once arose. But again, here we can recall the wise phrase of Paracelsus that the difference between medicine and poison is only in its quantity. That is, in other words, the greenhouse effect is useful only in small quantities, when the gases leading to the greenhouse effect, their concentration in the atmosphere is not high. When it becomes significant, this climatic phenomenon turns from a kind of medicine into a real dangerous poison.
How to minimize the negative consequences of the greenhouse effect
To overcome a problem, you need to eliminate its causes. In the case of the greenhouse effect, the sources that cause global warming must also be eliminated. In our opinion, first of all, it is necessary to stop deforestation, and, on the contrary, to plant new trees, shrubs, and create gardens more actively.
Refusal from gasoline cars, a gradual transition to electric cars or even bicycles (both good for health and for the environment) is also a small step in the fight against the greenhouse effect. And if many conscious people take this step, then this will be significant progress for improving the ecology of planet Earth - our common home.
Scientists are also developing a new alternative fuel that will be environmentally friendly, but when it will appear and become ubiquitous is still unknown.
And finally, you can quote the wise Indian leader White Cloud from the Ayoko tribe: “Only after the last tree is cut down, only after the last fish is caught and the last river is poisoned, only then will you understand that money cannot be eaten.”
Greenhouse effect, video
And finally, a thematic documentary about the greenhouse effect.
The greenhouse effect is a phenomenon in which the solar heat entering the Earth is retained at the Earth's surface by so-called greenhouse or greenhouse gases. These gases include the familiar carbon dioxide and methane, the content of which in the atmosphere is steadily increasing. This is facilitated primarily not only by the burning of gigantic volumes of fuel, but also by a number of other factors, including deforestation, emissions of freons into the atmosphere, improper agricultural practices and overgrazing of livestock. Deforestation is especially dangerous and undesirable. It will lead not only to water and wind erosion, thereby disturbing the soil cover, but will also continue the non-renewable loss of organic matter in the biosphere, the very thing that absorbs carbon dioxide from the atmosphere. It should also be noted that at least 25% of this gas contained in the atmosphere is due to unjustified deforestation in the northern and southern zones. Even more alarming is the evidence that deforestation and fuel combustion balance each other out in terms of carbon dioxide emissions. Forests also suffer due to their excessive use for recreation and recreation. Often the presence of tourists in such cases leads to mechanical damage to the trees and their subsequent illness and death. Mass visits also contribute to trampling of the soil and lower layers of vegetation.
The degeneration of forests with significant air pollution is very noticeable. Fly ash, coal and coke dust clog leaf pores, reduce light access to plants and weaken the assimilation process. Soil pollution with emissions of metal dust, arsenic dust in combination with superphosphate or sulfuric acid poisons the root system of plants, retarding its growth. Sulfur dioxide is also toxic to plants. Vegetation is completely destroyed under the influence of fumes and gases from copper smelters in the immediate vicinity. Damage to vegetation, and primarily to forests, is caused by acidic precipitation as a result of the spread of sulfur compounds over hundreds and thousands of kilometers. Acidic precipitation has a regional destructive effect on forest soils. A noticeable decrease in forest biomass is apparently also due to fires. Of course, plants are characterized by the process of photosynthesis, during which plants absorb carbon dioxide, which serves as biomass, but recently the level of pollution has increased so much that plants can no longer cope with it. According to scientists, every year all land vegetation absorbs 20–30 billion tons of carbon dioxide from the atmosphere in the form of its dioxide, and the Amazon alone absorbs up to 6 billion tons of harmful atmospheric impurities. Algae play an important role in the absorption of carbon dioxide.
Another problem of the modern dynamically developing world is the improper conduct of agriculture, which in some cases uses the slash-and-burn system, which has not yet been eliminated in the equatorial regions, and overgrazing of livestock, which leads to the same soil compaction. The problem of fuel combustion and the release of dangerous industrial gases such as freons is also traditional.
History of greenhouse effect research
An interesting point of view was put forward by the Soviet climatologist N. I. Budyko in 1962. According to his calculations, the concentration of atmospheric CO 2 is predicted to increase in 2000 to 380 parts per million, in 2025 - to 520 and in 2050. - up to 750. The average annual surface global air temperature will increase, in his opinion, compared to its value at the beginning of the twentieth century. by 0.9 degrees Celsius in 2000, by 1.8 degrees in 2025 and by 2.8 degrees in 2050. That is, we should not expect glaciation.
However, the study of the greenhouse effect began much earlier. The idea of the mechanism of the greenhouse effect was first outlined in 1827 by Joseph Fourier in the article “Note on the Temperatures of the Globe and Other Planets,” in which he considered the various mechanisms of formation of the Earth’s climate, while he considered both factors influencing the overall heat balance of the Earth ( heating by solar radiation, cooling due to radiation, internal heat of the Earth), as well as factors influencing heat transfer and temperatures of climatic zones (thermal conductivity, atmospheric and oceanic circulation).
When considering the influence of the atmosphere on the radiation balance, Fourier analyzed the experiment of M. de Saussure with a vessel covered with glass, blackened from the inside. De Saussure measured the temperature difference between the inside and outside of such a vessel exposed to direct sunlight. Fourier explained the increase in temperature inside such a “mini-greenhouse” compared to the external temperature by the action of two factors: blocking convective heat transfer (glass prevents the outflow of heated air from the inside and the influx of cool air from outside) and the different transparency of glass in the visible and infrared range.
It was the last factor that received the name of the greenhouse effect in later literature - absorbing visible light, the surface heats up and emits thermal (infrared) rays; Since glass is transparent to visible light and almost opaque to thermal radiation, the accumulation of heat leads to such an increase in temperature at which the number of thermal rays passing through the glass is sufficient to establish thermal equilibrium.
Fourier postulated that the optical properties of the Earth's atmosphere are similar to the optical properties of glass, that is, its transparency in the infrared range is lower than transparency in the optical range.
The conclusions of other geophysicists such as V.I. Lebedev are also known. He believes that an increase in the concentration of CO 2 in the air should not affect the earth's climate at all, while the productivity of terrestrial vegetation, and in particular grain crops, will increase.
Physicist B. M. Smirnov also points to the possibility of increasing yields. In this regard, he considers the accumulation of carbon dioxide in the atmosphere as a factor beneficial for humanity.
A different point of view is held by the so-called Club of Rome, founded in 1968 and the Americans came to the conclusion that there is a gradual increase in the amount of greenhouse gases in the atmosphere. The opinions of a number of scientists about the cyclical nature of climate are interesting, saying that there are “warm” and “cold” centuries. This is not to say that they are wrong, because everyone is right in their own way. That is, in modern climatology we clearly trace 3 directions:
Optimistic
Pessimistic
Neutral
Causes of the greenhouse effect
In the modern balance of consumption of organic matter, 45% in our country belongs to natural gas in terms of reserves of which we occupy 1st place in the world. Its advantage over other fossil fuels (fuel oil, coal, oil, etc.) is obvious: it has a lower carbon dioxide emission factor. In the global fuel balance, natural gas occupies a much more modest role - only 25%. Currently, the concentration of carbon dioxide in the atmosphere is 0.032% (in cities - 0.034%). Doctors say that the concentration of CO 2 in the air is harmless to human health up to a level of 1%, i.e. humanity still has enough time to solve this problem. The data from the RAS Institute is interesting. Thus, annual reports on air pollution problems provide data that Russia exhales 3.12 billion tons of carbon dioxide, with 1.84 kg per person per day. The lion's share of carbon dioxide is emitted by the car. Added to this are 500 million tons from forest fires, but overall in Russia the level of pollution is an order of magnitude lower than in foreign countries such as the USA. But the problem is not limited to carbon dioxide alone. Gases that create a greenhouse effect include a number of others, such as methane, so it is very important to be able to determine its real losses during production, transportation through pipelines, distribution in large cities and towns, and use in thermal and power plants. It should be noted that its concentration remained unchanged for a long time, and from the 19th to 20th centuries it began to grow rapidly.
According to scientists, the amount of oxygen in the atmosphere decreases annually by more than 10 million tons. If its consumption continues at this rate, then two-thirds of the total amount of free oxygen in the atmosphere and hydrosphere will be exhausted in just over 100 thousand years. Accordingly, the carbon dioxide content in the atmosphere will reach excessive concentrations.
According to research by Russian, French, and American scientists, the total level of these gases has reached its historical maximum over the past 420 thousand years, surpassing even emissions of natural origin, which include volcanism and the release of hydrates from the ocean floor. Proof of this is data from the “Pole of Cold” of the Russian Antarctic station Vostok, where polar explorers obtained an ice core with a thickness of 2547 m, clearly demonstrating this or similar data from glacial Tibet, one of the highest places on our planet.
It must be said that the natural greenhouse effect has always been characteristic of the Earth. It is with this that the age-old and not only cyclical climate is connected. A number of scientists also suggest that they are caused by a change in the Earth’s orbit relative to the Sun, but the inconsistency of this theory is obvious. Every year our planet passes 2 points of perihelion and aphelion, leading to a change in the planet’s orbit. Nevertheless, any significant changes, with the exception of the change of seasons, characteristic of other terrestrial planets such as Mars, do not occur. Large-scale changes occur extremely rarely, so there is no need to talk about the prevailing role of this factor.
Since the end of the 19th century, there has been a continuous debate between ecocentrists, who believe that a breakdown in cyclicality occurred with the beginning of industrialization, and anthropocentrists, who believe that this process is influenced not only by human economic activity. Here, first of all, it is necessary to note the differentiation of emissions. After all, even the United States emits only 20% of the global level, and the emissions of the “third world” countries, which after 1991 include Russia, do not exceed 10%.
But even standing aside from this debate, the evidence of climate warming becomes obvious. This is confirmed by a simple fact. Back in 1973 in the USSR, on November 7 - the day of the Great October Socialist Revolution, snow removal equipment walked in front of a column of demonstrators, but now there is no snow in early December and even in January! Continuing this topic, geographers have already included 1990, 1995, 1997 and the last 2 years in the “list of the warmest” over the past 600 years. And in general, the 20th century, despite a number of costs, was recognized as the “warmest” in 1200 years!
However, apparently this is how man works - the only creature on Earth in the literal sense of the word “sawing the tree on which he sits.” What I mean is that the above information discovered in America makes you at least think, but at the same time, in the southeast of this country (Florida), swamps are being drained for the construction of prestigious houses and sugar cane plantations.
Possible consequences of the greenhouse effect
Nature never forgives mistakes. Climate change from the greenhouse effect can reach, and in some cases exceed, our wildest expectations. In this context, the most dangerous and alarming is the melting of the polar ice caps, as a result of a general increase in temperature by 5 degrees. As a result, chain reactions akin to the “domino effect” will begin. The melting of glaciers will lead, first of all, to an increase in the level of the World Ocean by, at best, 5–7 meters, and in the future even up to 60 meters. Entire countries will disappear, in particular low-lying ones such as Bangladesh, Denmark, the Netherlands, and many port cities around the world such as Rotterdam and New York. All this will lead to the second “great migration of peoples”, this time from the low-lying zones, in which, according to UN estimates, about a billion people live. Moreover, if over the last 250-300 years the level of the World Ocean has risen by an average of 1 mm per year, then in the 20s of the twentieth century. its rise reached 1.4-1.5 mm per year, which is equivalent to an annual increase in oceanic water mass by 520-540 cubic meters. km. It is assumed that in the 20s of the XXI century. the rate of ocean level rise will exceed 0.5 cm per year. An increase in water mass will affect seismicity in different areas of the planet. By 2030, the Gulf Stream will disappear as a current. The consequence of this will be a decrease in the contrast between North and South.
Other existing ecosystems will also change. In particular, due to the change in the oblateness of the planet in Africa and Asia, crop yields will fall and the risk of catastrophic floods will increase in Europe and on the east coast of the United States, where coastal erosion will also occur. Thus, a number of catastrophically radical climate changes will occur in the UK, including a manifold increase in the frequency of hot and dry summers similar to the summer of 1995. Two such summers in a row will lead to drought, crop failure and famine. Aquitaine, Gascony, and Normandy will disappear from the map of France. In place of Paris there will be an ocean. The sword of Damocles hangs over Venice. Severe droughts will engulf Australia, the states of Texas, California, and long-suffering Florida. Where rain was very rare, it will become even rarer, in other wetter areas the amount of precipitation will increase even more. Average annual temperatures in Algeria will increase, glaciers in the Caucasus and Alps will disappear, and in the Himalayas and Andes they will decrease by 1/5, permafrost will disappear in Russia, calling into question the existence of northern cities. Siberia will change radically. The valleys of many rivers such as the Rio Grande, Magdalena, Amazon, and Parana will disappear. The Panama Canal will lose its importance. So, if we agree with the calculations of some scientists, then by the end of the first quarter of the 21st century. As a result of warming caused by an increase in CO 2 concentration in the atmosphere, the climate of Moscow will be similar to the modern climate of humid Transcaucasia.
There will be a restructuring of the entire atmospheric circulation system with corresponding changes in the thermal regime and humidification. The process of reforming geographical zones will begin with their “shift” to higher latitudes at a distance of up to 15 degrees. It must be taken into account that the atmosphere is a very dynamic system and can change extremely quickly; As for other components of the geosphere, they are more conservative. Thus, it takes hundreds of years for radical changes in soil cover. A situation is possible when the most fertile soils, for example chernozems, will find themselves in desert climatic conditions, and the already waterlogged and swampy taiga lands will receive even more precipitation. Desert areas may increase dramatically. Indeed, even at present, desertification processes are developing on 50-70 thousand square meters. km of cultivated areas. Warming will lead to an increase in the number of cyclones, including hurricanes. It is also important that certain animal populations may simply disappear from the face of the Earth, while a number of others may decline catastrophically. There is no doubt that the advancement of the tropical and subtropical zones will lead to an expansion of the habitats of pathogenic microbes and bacteria. Energy will also incur significant costs. Everything wasn't so bad if it weren't for the speed of everything that was happening. A person does not have time to adapt to changed conditions, because 50 centuries ago, when a similar phenomenon was observed, there were no factors accelerating it tens or even hundreds of times. Especially in this regard, developing countries that have just begun to create their own economies suffer.
On the other hand, warming promises us great opportunities that people may not yet be aware of. There is no need to immediately refute these few statements. After all, man, in the words of Vernadsky, “a great geological force,” can reorganize his economy in a new way, for which nature, in turn, will provide great opportunities. So the forests will move further north and cover, in particular, all of Alaska; the opening of rivers in the Northern Hemisphere will occur 2 weeks earlier compared to the same period in the 19th century. This will give a “new breath” to river shipping. Agronomists will undoubtedly not be against increasing the growing season of plants in Europe by 1 month; there will be more wood. There are calculations by physicists according to which, when the concentration of CO 2 in the atmosphere doubles, the air temperature will increase by no more than 0.04 degrees Celsius. Thus, an increase in CO 2 concentration on such a scale may be more likely to be beneficial for agricultural production, because should be accompanied by an increase in the intensity of photosynthesis (by 2-3%).
Migratory birds will arrive earlier and stay with us longer than now. Winters will become significantly warmer, and summers will lengthen and become hotter; the heating season will objectively be shortened in cities where warming will average about 3 degrees. In Russia, agriculture in the future may move to the north, as N.S. Khrushchev wanted, but the most important thing is that Russia will be able to raise these regions, destroyed by the liberal reforms of the 90s, by connecting them into a single road network, we are talking about about the construction of a fundamentally new railway from Yakutsk further to Anadyr and Alaska through the Bering Strait and the possible continuation of existing ones such as the Transpolar Railway.
The greenhouse effect is an increase in the temperature of the earth's surface due to the heating of the lower layers of the atmosphere by the accumulation of greenhouse gases. As a result, the air temperature is higher than it should be, and this leads to irreversible consequences such as climate change and global warming. Several centuries ago this environmental problem existed, but was not so obvious. With the development of technology, the number of sources that provide the greenhouse effect in the atmosphere increases every year.
Causes of the greenhouse effect
the use of combustible minerals in industry - coal, oil, natural gas, the combustion of which releases huge amounts of carbon dioxide and other harmful compounds into the atmosphere;
transport – cars and trucks emit exhaust gases, which also pollute the air and increase the greenhouse effect;
deforestation, which absorbs carbon dioxide and releases oxygen, and with the destruction of every tree on the planet, the amount of CO2 in the air increases;
forest fires are another source of destruction of plants on the planet;
an increase in population affects the increase in demand for food, clothing, housing, and to ensure this, industrial production is growing, which increasingly pollutes the air with greenhouse gases;
agrochemicals and fertilizers contain varying amounts of compounds, the evaporation of which releases nitrogen, one of the greenhouse gases;
The decomposition and combustion of waste in landfills contributes to the increase in greenhouse gases.
The influence of the greenhouse effect on climate
Considering the results of the greenhouse effect, we can determine that the main one is climate change. As the air temperature increases every year, the waters of the seas and oceans evaporate more intensely. Some scientists predict that in 200 years the phenomenon of “drying” of the oceans will become noticeable, namely a significant decrease in water levels. This is one side of the problem. The other is that rising temperatures lead to the melting of glaciers, which contributes to rising water levels in the World Ocean and leads to the flooding of the coasts of continents and islands. The increase in the number of floods and flooding of coastal areas indicates that the level of ocean waters is increasing every year.
An increase in air temperature leads to the fact that areas that are little moistened by precipitation become arid and unsuitable for life. Crops are destroyed here, which leads to a food crisis for the population of the area. Also, there is no food for the animals, since plants die out due to lack of water.
First of all, we need to stop deforestation and plant new trees and shrubs, as they absorb carbon dioxide and produce oxygen. By using electric vehicles, the amount of exhaust gases will be reduced. In addition, you can switch from cars to bicycles, which is more convenient, cheaper and better for the environment. Alternative fuels are also being developed, which, unfortunately, are slowly being introduced into our daily lives.
19. Ozone layer: significance, composition, possible causes of its destruction, protective measures taken.
Earth's ozone layer- this is the region of the Earth's atmosphere in which ozone is formed - a gas that protects our planet from the harmful effects of ultraviolet radiation.
Destruction and depletion of the Earth's ozone layer.
The ozone layer, despite its enormous importance for all living things, is a very fragile barrier to ultraviolet rays. Its integrity depends on a number of conditions, but nature nevertheless came to a balance in this matter, and for many millions of years the Earth’s ozone layer successfully coped with the mission entrusted to it. The processes of formation and destruction of the ozone layer were strictly balanced until man appeared on the planet and reached the current technical level in his development.
In the 70s twentieth century, it was proven that many substances actively used by humans in economic activities can significantly reduce ozone levels in Earth's atmosphere.
Substances that destroy the Earth's ozone layer include fluorochlorocarbons - freons (gases used in aerosols and refrigerators, consisting of chlorine, fluorine and carbon atoms), combustion products during high-altitude aircraft flights and rocket launches, i.e. substances whose molecules contain chlorine or bromine.
These substances, released into the atmosphere at the surface of the Earth, reach the top within 10-20 years. ozone layer boundaries. There, under the influence of ultraviolet radiation, they decompose, forming chlorine and bromine, which, in turn, interact with stratospheric ozone, significantly reducing its amount.
Causes of destruction and depletion of the Earth's ozone layer.
Let us consider again in more detail the reasons for the destruction of the Earth's ozone layer. At the same time, we will not consider the natural decay of ozone molecules. We will focus on human economic activity.
