All about the greenhouse effect. Global warming and greenhouse effect

IN Lately Climatologists and other scientists are persistently calling on the public and politicians to pay close attention to the problem of the “greenhouse effect.”

Official science believes that “global” warming of the climate on Earth is caused by increased technogenic human activity, an increase in the volume of carbon dioxide in the planet's atmosphere in the form of exhaust gases from transport and industrial emissions. But is this really so?

Content of greenhouse gases in the atmosphere

As geological studies show, before the start of the industrial era in human history, the content of carbon dioxide in the Earth's air ocean was about 0.027%. Now this figure fluctuates between 0.03–0.04%. About 50 million years ago, its level was 1-3%, and then plant and animal life flourished in exuberant forms and in abundance of species.

Benefits of the greenhouse effect

This effect is now used by agronomists when growing cultivated plants– it is enough to create a carbon dioxide concentration of about 1% in the greenhouse air, and active plant growth begins and their productivity increases. Low level of this chemical compound in the atmosphere (less than 0.015%), on the contrary, is harmful to flora and inhibits plant development. There is also evidence that orange groves in California produced much better fruit 150 years ago than they do now. And this was associated with a temporary increase in carbon dioxide levels in the air.

Related materials:

What's happened ozone layer and why is its destruction harmful?

Is the greenhouse effect dangerous for humans?

As for humans, the upper limit of carbon dioxide content in the air that is hazardous to health is more than 5–8%. It turns out that even doubling the current amount of this gas will not be noticeable to animals, and plants will begin to develop better. According to some estimates, the increase in the amount of “greenhouse” gases as a result of mankind’s technogenic activities is about 0.002% per year. At the current rate of growth in greenhouse gas content, it will take at least 195 years to double it.

According to climatologists who are proponents of the “greenhouse effect” theory, an increase in carbon dioxide from 0.028 to 0.039% over the past 150 years has led to an increase in average annual temperature by about 0.8 degrees.

Periods of warming and cooling on Earth

In the history of the Earth there have been many periods of warming and cooling that were not associated with changes in carbon dioxide in the atmosphere. In the period from 1000 to 1200 AD there was a warming, grapes were cultivated in England and wine was made. Then the Little Ice Age began, when temperatures dropped and complete freezing of the Thames became a common occurrence. From the end of the 17th century, temperatures began to rise slowly, although between 1940 and 1970 there was a “rollback” towards lower average temperatures, which caused an “ice age” panic in society. Temperature fluctuations within 0.6–0.9 degrees can be considered normal. The existence of a small “ice age” and other “inconvenient” facts are kept silent in the circles of climate scientists.

The average surface temperature of the Earth (or another planet) increases due to the presence of its atmosphere.

Gardeners are very familiar with this physical phenomenon. The inside of the greenhouse is always warmer than the outside, and this helps to grow plants, especially in the cold season. You may feel a similar effect when you are in a car. The reason for this is that the Sun, with a surface temperature of about 5000°C, emits mainly visible light - part electromagnetic spectrum to which our eyes are sensitive. Because the atmosphere is largely transparent to visible light, solar radiation easily penetrates the Earth's surface. Glass is also transparent to visible light, so Sun rays pass inside the greenhouse, and their energy is absorbed by plants and all objects located inside. Further, according to the Stefan-Boltzmann law, every object emits energy in some part of the electromagnetic spectrum. Objects with a temperature of about 15°C - the average temperature at the Earth's surface - emit energy in the infrared range. Thus, objects in a greenhouse emit infrared radiation. However, infrared radiation cannot easily pass through glass, so the temperature inside the greenhouse rises.

Planet with stable atmosphere, such as the Earth, experiences almost the same effect - in on a global scale. To support constant temperature, The Earth itself needs to emit as much energy as it absorbs from the visible light emitted towards us by the Sun. The atmosphere serves as glass in a greenhouse - it is not as transparent to infrared radiation as it is to sunlight. Molecules of various substances in the atmosphere (the most important of them are carbon dioxide and water) absorb infrared radiation, acting as greenhouse gases . Thus, infrared photons emitted by the earth's surface do not always go directly into space. Some of them are absorbed by molecules greenhouse gases in the atmosphere. When these molecules re-radiate the energy they have absorbed, they can radiate it both outward into space and inward, back toward the Earth's surface. The presence of such gases in the atmosphere creates the effect of covering the Earth with a blanket. They cannot stop heat from escaping outward, but they do allow heat to remain near the surface for more for a long time, so the Earth's surface is much warmer than it would be in the absence of gases. Without the atmosphere, the average surface temperature would be -20°C, well below the freezing point of water.

It is important to understand that the greenhouse effect has always existed on Earth. Without the greenhouse effect caused by carbon dioxide in the atmosphere, the oceans would have frozen long ago, and higher forms life would not have appeared. Currently, the scientific debate about the greenhouse effect is on the issue global warming: aren’t we, people, disturbing the energy balance of the planet too much as a result of burning fossil fuels and so on? economic activity while adding too much carbon dioxide to the atmosphere? Today, scientists agree that we are responsible for increasing the natural greenhouse effect by several degrees.

Greenhouse effect takes place not only on Earth. In fact, the strongest greenhouse effect we know of is on our neighboring planet, Venus. The atmosphere of Venus consists almost entirely of carbon dioxide, and as a result the surface of the planet is heated to 475 ° C. Climatologists believe that we have avoided such a fate thanks to the presence of oceans on Earth. Oceans absorb atmospheric carbon and it accumulates in rocks such as limestone - thereby removing carbon dioxide from the atmosphere. There are no oceans on Venus, and all the carbon dioxide that volcanoes emit into the atmosphere remains there. As a result, we observe on Venus ungovernable 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, and improper Agriculture 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 decline organic matter biosphere, the same one 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 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 root system 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, in a 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 incorrect practice 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 hazardous emissions is also traditional. industrial gases such as freons.

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 “A Note on the Temperatures of the Globe and Other Planets,” in which he considered various mechanisms for the 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 Earth), and factors influencing heat transfer and temperature 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 in contrast to 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 in general 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 also 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 major cities and populated areas, 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 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, which clearly demonstrates 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 the breakdown in cyclicality occurred with the beginning of industrialization, and anthropocentrists, who believe that this process influences not only 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 primarily to a rise in sea levels in best case scenario by 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 the annual increase in oceanic water mass for 520-540 cc. 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, according to 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 liberal reforms 90s, connecting them into a single road network, we are talking 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 Highway.

Introduction

1. Greenhouse effect: historical information and causes

1.1. Historical information

1.2. Causes

2. Greenhouse effect: mechanism of formation, strengthening

2.1. The mechanism of the greenhouse effect and its role in biosphere

processes

2.2. Increased greenhouse effect in the industrial era

3. Consequences of the increased greenhouse effect

Conclusion

List of used literature

Introduction

The main source of energy that supports life on Earth is solar radiation - electromagnetic radiation from the Sun that penetrates the Earth's atmosphere. Solar energy also supports all atmospheric processes that determine the change of seasons: spring-summer-autumn-winter, as well as changes in weather conditions.

About half solar energy falls in the visible part of the spectrum, which we perceive as sunlight. This radiation passes quite freely through the earth's atmosphere and is absorbed by the surface of land and oceans, heating them. But after all, solar radiation reaches the Earth every day for many millennia, why, in this case, does the Earth not overheat and turn into a small Sun?

The fact is that the earth, the water surface, and the atmosphere, in turn, also emit energy, only in a slightly different form - as invisible infrared, or thermal radiation.

On average, quite a long time in space Exactly as much energy goes out in the form of infrared radiation as it comes in in the form of sunlight. Thus, the thermal equilibrium of our planet is established. The whole question is at what temperature this equilibrium will be established. If there were no atmosphere, the average temperature of the Earth would be -23 degrees. The protective effect of the atmosphere, which absorbs part of the infrared radiation of the earth's surface, leads to the fact that in reality this temperature is +15 degrees. An increase in temperature is a consequence of the greenhouse effect in the atmosphere, which intensifies with an increase in the amount of carbon dioxide and water vapor in the atmosphere. These gases absorb infrared radiation best.

In recent decades, the concentration of carbon dioxide in the atmosphere has been increasing more and more. This happens because; that the volume of burning fossil fuels and wood increases every year. As a result, the average air temperature at the Earth's surface increases by about 0.5 degrees per century. If the current rate of fuel combustion, and therefore the increase in greenhouse gas concentrations, continues in the future, then, according to some forecasts, even greater climate warming is expected in the next century.

1. Greenhouse effect: historical information and causes

1.1. Historical information

The idea of the mechanism of the greenhouse effect was first outlined in 1827 by Joseph Fourier in the article “A Note on the Temperatures of the Globe and Other Planets,” in which he considered various mechanisms 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), and factors influencing heat transfer and temperatures of climatic zones (thermal conductivity, atmospheric and oceanic circulation ).

1.2. Causes

The essence of the greenhouse effect is as follows: the Earth receives energy from the Sun, mainly in the visible part of the spectrum, and itself radiates into outer space, mainly infrared rays.

However, many gases contained in its atmosphere - water vapor, CO2, methane, nitrous oxide, etc. - are transparent to visible rays, but actively absorb infrared rays, thereby retaining some of the heat in the atmosphere.

In recent decades, the content of greenhouse gases in the atmosphere has increased greatly. New, previously non-existent substances with a “greenhouse” absorption spectrum have also appeared - primarily fluorocarbons.

The gases that cause the greenhouse effect are not only carbon dioxide (CO2). These also include methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6). However, it is the combustion of hydrocarbon fuels, accompanied by the release of CO2, that is considered the main cause of pollution.

The reason for the rapid increase in the amount of greenhouse gases is obvious - humanity now burns as much fossil fuel per day as it was formed over thousands of years during the formation of oil, coal and gas deposits. From this “push” the climate system came out of “equilibrium” and we see a greater number of secondary negative phenomena: especially hot days, droughts, floods, sudden changes in weather, and this is what causes the greatest damage.

According to researchers, if nothing is done, global CO2 emissions will quadruple over the next 125 years. But we must not forget that Substantial part future sources of pollution has not yet been built. Over the past hundred years, temperatures in the northern hemisphere have increased by 0.6 degrees. The predicted temperature increase over the next century will be between 1.5 and 5.8 degrees. The most likely option is 2.5-3 degrees.

However, climate change is not just about rising temperatures. The changes also affect other climatic phenomena. Not only extreme heat, but also severe sudden frosts, floods, mudflows, tornadoes, and hurricanes are explained by the effects of global warming. The climate system is too complex to be expected to change uniformly and uniformly in all parts of the planet. And scientists see the main danger today precisely in the growth of deviations from average values - significant and frequent temperature fluctuations.

2. Greenhouse effect: mechanism, enhancement

2.1 The mechanism of the greenhouse effect and its role in biosphere processes

The main source of life and all natural processes on Earth is the radiant energy of the Sun. The energy of solar radiation of all wavelengths entering our planet per unit time per unit area perpendicular to the sun's rays is called the solar constant and is 1.4 kJ/cm2. This is only one two-billionth of the energy emitted by the surface of the Sun. From total number The atmosphere absorbs -20% of solar energy entering the Earth. Approximately 34% of the energy penetrating deep into the atmosphere and reaching the Earth's surface is reflected by atmospheric clouds, aerosols contained in it, and the Earth's surface itself. Thus, -46% of solar energy reaches the earth's surface and is absorbed by it. In turn, the surface of land and water emits long-wave infrared (thermal) radiation, which partly goes into space and partly remains in the atmosphere, being retained by the gases included in its composition and heating the ground layers of air. This isolation of the Earth from outer space created favorable conditions for the development of living organisms.

The nature of the greenhouse effect of atmospheres is due to their different transparency in the visible and far infrared ranges. The wavelength range 400-1500 nm (visible light and near-infrared) accounts for 75% of solar radiation energy; most gases do not absorb in this range; Rayleigh scattering in gases and scattering on atmospheric aerosols do not prevent radiation of these wavelengths from penetrating into the depths of atmospheres and reaching the surface of planets. sunlight is absorbed by the surface of the planet and its atmosphere (especially radiation in the near UV and IR regions) and heats them. The heated surface of the planet and the atmosphere emit in the far infrared range: for example, in the case of Earth (), 75% of thermal radiation falls in the range of 7.8-28 microns, for Venus - 3.3-12 microns.

The atmosphere containing gases that absorb in this region of the spectrum (the so-called greenhouse gases - H2O, CO2, CH4, etc.) is significantly opaque for such radiation directed from its surface into outer space, that is, it has a large optical thickness. Due to such opacity, the atmosphere becomes a good heat insulator, which, in turn, leads to the fact that the reradiation of absorbed solar energy into outer space occurs in the upper cold layers of the atmosphere. As a result, the effective temperature of the Earth as a radiator turns out to be lower than the temperature of its surface .

Thus, the delayed thermal radiation coming from the earth's surface (like a film over a greenhouse) received the figurative name of the greenhouse effect. Gases that trap thermal radiation and prevent heat from escaping into space are called greenhouse gases. Thanks to the greenhouse effect, the average annual temperature at the Earth's surface over the last millennium has been approximately 15°C. Without the greenhouse effect, this temperature would drop to -18°C and the existence of life on Earth would become impossible. The main greenhouse gas in the atmosphere is water vapor, which traps 60% of the Earth's thermal radiation. The content of water vapor in the atmosphere is determined by the planetary water cycle and (with strong latitudinal and altitudinal fluctuations) is almost constant. Approximately 40% of the Earth's thermal radiation is trapped by other greenhouse gases, including more than 20% by carbon dioxide. The main natural sources of CO2 in the atmosphere are volcanic eruptions and natural forest fires. At the dawn of the geobiochemical evolution of the Earth, carbon dioxide entered the World Ocean through underwater volcanoes, saturated it and was released into the atmosphere. There are still no accurate estimates of the amount of CO2 in the atmosphere at the early stages of its development. Based on the results of the analysis of basalt rocks of underwater ridges in the Pacific and Atlantic Oceans American geochemist D. Marais concluded that the CO2 content in the atmosphere in the first billion years of its existence was a thousand times higher than at present - about 39%. Then the air temperature in the surface layer reached almost 100°C, and the water temperature in the World Ocean was approaching the boiling point (the “supergreenhouse” effect). With the advent of photosynthetic organisms and chemical processes for fixing carbon dioxide, a powerful mechanism for removing CO2 from the atmosphere and ocean into sedimentary rocks began to operate. The greenhouse effect began to gradually decrease until the equilibrium in the biosphere reached that which existed before the era of industrialization and which corresponds to the minimum content of carbon dioxide in the atmosphere - 0.03%. In the absence of anthropogenic emissions, the carbon cycle of terrestrial and aquatic biota, hydrosphere, lithosphere and atmosphere was in equilibrium. The release of carbon dioxide into the atmosphere due to volcanic activity is estimated at 175 million tons per year. Precipitation in the form of carbonates binds about 100 million tons. The oceanic carbon reserve is large - it is 80 times greater than the atmospheric one. Three times more carbon than in the atmosphere is concentrated in biota, and with an increase in CO2, the productivity of terrestrial vegetation increases.

Greenhouse effect - the process of rising temperatures at the earth's surface due to increasing concentrations of greenhouse gases (Figure 3).

Greenhouse gases– these are gaseous compounds that intensively absorb infrared rays (heat rays) and contribute to heating the surface layer of the atmosphere; these include: primarily CO 2 (carbon dioxide), as well as methane, chlorofluorocarbons (CFCs), nitrogen oxides, ozone, water vapor.

These impurities prevent long-wave thermal radiation from the earth's surface. Some of this absorbed thermal radiation returns back to the earth's surface. Consequently, with an increase in the concentration of greenhouse gases in the ground layer of the atmosphere, the intensity of absorption of infrared radiation emanating from the earth’s surface also increases, and therefore the air temperature increases (climate warming).

An important function of greenhouse gases is to maintain a relatively constant and moderate temperature on the surface of our planet. For maintaining favorable temperature conditions At the Earth's surface, carbon dioxide and water are primarily responsible.

Figure 3. Greenhouse effect

The earth is in thermal equilibrium with its surroundings. This means that the planet emits energy into space at a rate equal to the rate at which it absorbs solar energy. Since the Earth is a relatively cold body with a temperature of 254 K, the radiation of such cold bodies falls on the long-wave (low energy) part of the spectrum, i.e. The maximum intensity of the Earth's radiation is located near the wavelength of 12,000 nm.

Most of this radiation is retained by CO 2 and H 2 O, which absorbs it in the infrared region, thereby preventing heat from dissipating and maintaining a uniform temperature suitable for life at the Earth’s surface. Water vapor plays important role in maintaining the temperature of the atmosphere at night, when earth's surface emits energy into outer space and does not receive solar energy. In deserts with a very arid climate, where the concentration of water vapor is very low, it is unbearably hot during the day, but very cold at night.

The main reasons for the strengthening of the greenhouse effect– significant release of greenhouse gases into the atmosphere and an increase in their concentrations; what happens due to the intensive burning of fossil fuels (coal, natural gas, petroleum products), removal of vegetation: deforestation; drying out of forests due to pollution, burning of vegetation during fires, etc. As a result, the natural balance between the consumption of CO 2 by plants and its intake during respiration (physiological, decay, combustion) is disrupted.

As scientists write, with a probability of more than 90%, it is human activity in burning natural fuels and the resulting greenhouse effect that largely explains global warming in the last 50 years. Processes caused by human activity are like a train that has lost control. It is almost impossible to stop them; warming will continue for at least several centuries, or even a whole millennium. As ecologists have established, until now the lion's share The world's oceans absorbed heat, but the capacity of this gigantic battery was running out - the water warmed up to a depth of three kilometers. The result is global climate change.

Concentration of the main greenhouse gas(CO 2) in the atmosphere at the beginning of the 20th century was » 0.029%, by now it has reached 0.038%, i.e. increased by almost 30%. If current impacts on the biosphere are allowed to continue, by 2050 the concentration of CO 2 in the atmosphere will double. In this connection, it is predicted that the temperature on Earth will increase by 1.5 °C - 4.5 °C (in the polar regions up to 10 °C, in the equatorial regions - 1 °C -2 °C).

This, in turn, can lead to a critical increase in atmospheric temperature in arid zones, which will lead to the death of living organisms and a decrease in their vital activity; desertification of new territories; melting of polar and mountain glaciers, which means raising the level of the world ocean by 1.5 m, flooding coastal zones, increased storm activity, population migration.

Consequences of global warming:

1. As a result of global warming, it is predicted change in atmospheric circulation , changes in precipitation distribution, changes in the structure of biocenoses; in a number of areas, a decrease in agricultural yields.

2. Global climate change . Australia will suffer more. Climatologists predict a climate catastrophe for Sydney: by 2070, the average temperature in this Australian metropolis will rise by about five degrees, forest fires will devastate its surroundings, and giant waves will destroy sea beaches. Europe will be devastated by climate change. The ecosystem will be destabilized by relentlessly rising temperatures, EU scientists predict in a report. In the north of the continent, crop yields will increase as the growing season and frost-free period increase. The already warm and arid climate of this part of the planet will become even warmer, which will lead to droughts and the drying out of many fresh water reservoirs ( Southern Europe). These changes will pose a real challenge for farmers and foresters. In Northern Europe, warm winters will be accompanied by increased precipitation. Warming in the north of the region will also lead to positive phenomena: the expansion of forests and increased yields. However, they will go hand in hand with flooding, the destruction of coastal areas, the disappearance of some animal and plant species, and the melting of glaciers and permafrost areas. IN Far Eastern and Siberian regions the number of cold days will decrease by 10-15, and in the European part - by 15-30.

3. Global climate change is already costing humanity 315 thousand lives annually, and this figure is constantly increasing every year. It causes diseases, droughts and other weather anomalies that are already killing people. The organization's experts also provide other data - according to their estimates, currently more than 325 million people, usually from developing countries, are affected by climate change. Experts estimate the impact of global warming on the global economy at $125 billion in damage annually, and by 2030 this amount could rise to $340 billion.

4. Examination 30 glaciers V different regions A survey of the globe by the World Glacier Watch showed that in 2005 the thickness of the ice cover decreased by 60-70 centimeters. This figure is 1.6 times the annual average of the 90s and 3 times the average of the 1980s. Some experts believe that, given that the thickness of the glaciers is only a few tens of meters, if their melting continues at this rate, in a few decades the glaciers will disappear completely. The most dramatic processes of glacier melting have been observed in Europe. Thus, the Norwegian Breidalblikkbrea glacier lost more than three meters in 2006, which is 10 times more than in 2005. Threatening melting of glaciers has been noted in Austria, Switzerland, Sweden, France, Italy and Spain. In the area of the Himalayan mountains. The current trend of melting glaciers suggests that rivers like the Ganges, Indus, Brahmaputra (the highest river in the world) and other rivers crossing the northern plain of India may become seasonal rivers in the near future due to climate change.

5. Swift thawing permafrost Due to climate warming, today it poses a serious threat to the Russian northern regions, half of which are located in the so-called “permafrost zone”. Experts from the Ministry of Emergency Situations of the Russian Federation give forecasts: according to their calculations, the area of permafrost in Russia over the next 30 years will decrease by more than 20%, and the depth of soil thawing - by 50%. The greatest changes in climate may occur in the Arkhangelsk region, the Komi Republic, Khanty-Mansiysk Autonomous Okrug and Yakutia. Experts predict that the thawing of permafrost will lead to significant changes in the landscape, flooding of rivers, and the formation of thermokarst lakes. In addition, due to the thawing of permafrost, the rate of erosion of the Russian Arctic coasts will increase. Paradoxically, due to changes in the coastal landscape, the territory of Russia may be reduced by several tens of square kilometers. Due to climate warming from erosion coastline others suffer too Nordic countries. For example, the process of wave erosion will lead [http://ecoportal.su/news.php?id=56170] to the complete disappearance of the northernmost island of Iceland by 2020. The island of Kolbeinsey, which is considered the northernmost point of Iceland, will completely disappear under water by 2020 as a result of accelerating the process of abrasion - wave erosion of the coast.

6. World ocean level by 2100 could rise by 59 centimeters, according to a report by a UN expert group. But this is not the limit; if the ice of Greenland and Antarctica melts, then the level of the World Ocean may rise even higher. The location of St. Petersburg will then be indicated only by the top of the dome of St. Isaac's Cathedral and the spire of the Peter and Paul Fortress sticking out of the water. A similar fate will befall London, Stockholm, Copenhagen and other major coastal cities.

7. Tim Lenton, a climate expert at the University of East Anglia and his colleagues, using mathematical calculations, found that an increase in average annual temperature of even 2°C over 100 years would cause 20-40% of the deaths. Amazonian forests due to the impending drought. A 3°C rise in temperature will cause the death of 75% of forests within 100 years, and a 4°C rise in temperature will cause the disappearance of 85% of all Amazon forests. And they absorb CO 2 most efficiently (Photo: NASA, presentation).

8. At the current rate of global warming, up to 3.2 billion people on the globe will face the problem by 2080 shortage drinking water . Scientists note that water difficulties will primarily affect Africa and the Middle East, but a critical situation could also develop in China, Australia, parts of Europe and the United States. The UN has published a list of countries that will be most affected by climate change. It is led by India, Pakistan and Afghanistan.

9. Climate migrants . Global warming will lead to the fact that by the end of the 21st century various categories For refugees and migrants, another one may be added - climate change. By 2100, the number of climate migrants could reach about 200 million people.

None of the scientists doubt that warming exists - it is obvious. But there are alternative points of view. For example, corresponding member of the Russian Academy of Sciences, doctor geographical sciences, professor, head of the department of rational environmental management, Moscow State University Andrey Kapitsa, considers climate change normal natural phenomenon. There is global warming, it alternates with global cooling.

Supporters "classical" approach to the problem of the greenhouse effect are based on the assumption of the Swedish scientist Svante Arrhenius about the heating of the atmosphere as a result of the fact that “greenhouse gases” freely transmit solar rays to the surface of the Earth and at the same time delay the radiation of the earth’s heat into space. However, heat exchange processes in the earth's atmosphere turned out to be much more complicated. The gas “layer” regulates the flow of solar heat differently than the glass of a home greenhouse.

In fact, gases such as carbon dioxide do not cause the greenhouse effect. This has been convincingly proven by Russian scientists. Academician Oleg Sorokhtin, working at the Institute of Oceanology of the Russian Academy of Sciences, was the first to create a mathematical theory of the greenhouse effect. From his calculations, confirmed by measurements on Mars and Venus, it follows that even significant emissions of man-made carbon dioxide into the Earth’s atmosphere practically do not change the Earth’s thermal regime and do not create a greenhouse effect. On the contrary, we should expect a slight, fraction of a degree, cooling.

It was not the increased CO2 content in the atmosphere that led to warming, but As a result of warming, gigantic volumes of carbon dioxide were released into the atmosphere - mind you, without any human participation. 95 percent of CO 2 is dissolved in the world's oceans. It is enough for the water columns to warm up by half a degree - and the ocean will “exhale” carbon dioxide. Volcanic eruptions and forest fires also make a significant contribution to pumping CO 2 into the earth's atmosphere. Despite all the costs of industrial progress, the emission of greenhouse gases from the pipes of factories and thermal power plants does not exceed several percent of the total carbon dioxide turnover in nature.

There have been ice ages that were followed by global warming, and now we are in a period of global warming. Normal climate fluctuations, which are associated with fluctuations in the activity of the Sun and the Earth's orbit. Not at all with human activity.

We were able to look 800 thousand years ago into the Earth's past thanks to a well drilled into the thickness of a glacier in Antarctica (3800 m).

Using air bubbles preserved in the core, they determined the temperature, age, and carbon dioxide content and obtained curves for approximately 800 thousand years. Based on the ratio of oxygen isotopes in these bubbles, scientists determined the temperature at which snow fell. The findings cover most Quaternary period. Of course, in the distant past, man could not influence nature. But it was found that the CO 2 content then changed very much. Moreover, each time it was warming that preceded an increase in CO 2 concentration in the air. The theory of the greenhouse effect suggests the reverse sequence.

There are certain ice ages that alternate with periods of warming. Now we are just in a period of warming, and it has been going on since the Little Ice Age, which was in the 15th - 16th centuries; since the 16th century, there has been a warming of approximately one degree per century.

But what is called the “greenhouse effect” is not a proven fact. Physicists show that CO 2 does not affect the greenhouse effect.

In 1998, former President of the US National Academy of Sciences Frederick Seitz submitted a petition to the scientific community calling on the US and other governments to reject the Kyoto agreements to limit greenhouse gas emissions. The petition was accompanied by a survey from which it follows that the Earth has been warming over the past 300 years. And influence human activity climate change has not been reliably established. In addition, Seitz argues that increased CO2 stimulates photosynthesis in plants and thereby contributes to increased agricultural productivity and accelerated forest growth. The petition was signed by 16 thousand scientists. However, the Clinton administration brushed aside these appeals, making it clear that the debate about the nature of global climate change was over.

In fact, Cosmic factors lead to serious climate changes. Temperature is changed by fluctuations in solar activity, as well as changes in the tilt of the earth's axis and the period of revolution of our planet. Fluctuations of this kind are known to have led to ice ages in the past.

The issue of global warming is a political issue. And here there is a struggle between two directions. One direction is those who use fuel, oil, gas, coal. They prove in every possible way that harm is caused by the transition to nuclear fuel. And supporters nuclear fuel prove the opposite, that just the opposite - gas, oil, coal release CO 2 and cause warming. This is a struggle between two large economic systems.

Publications on this topic are full of gloomy prophecies. I do not agree with such assessments. An increase in average annual temperature within one degree per century will not lead to fatal consequences. It takes a huge amount of energy to melt the ice of Antarctica, the boundaries of which have practically not shrunk over the entire period of observation. At least in the 21st century, climate disasters do not threaten humanity.

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