Introduction
AT recent times human activities have an unprecedented scale and intensity of impact on the environment and global life support systems. Proof of this is one of the many environmental problems - global warming - the greenhouse effect. Soon the atmosphere will become impervious to heat, and the consequences can be very global - the inevitable rise in the level of the world ocean as a result of the melting of continental and mountain glaciers, sea ice, thermal expansion of ocean waters. Such climate warming will cause serious changes in environmental conditions in the tundra, in the “permafrost” zones: seasonal thawing of soils will increase, which will pose a threat to roads, buildings and communications, the process of swamping will become more active, and the condition of forests on permafrost will worsen.
Accumulation carbon dioxide in the atmosphere is one of the main causes of the greenhouse effect. Carbon dioxide acts in the atmosphere like glass in a greenhouse: it lets solar radiation through and does not let Earth's infrared (thermal) radiation back into space. The content of greenhouse gases - CO2, methane, etc. - is steadily increasing. Carbon dioxide in the atmosphere acts as a powerful absorber of terrestrial radiation that would otherwise be scattered into outer space. By absorbing and releasing this radiation energy, carbon dioxide makes the atmosphere warmer than it would otherwise be.
Photosynthesis contributes to the reduction of carbon dioxide. Plants absorb CO2 from the air and build their biomass from it. All land vegetation absorbs from the atmosphere about 20-30 billion tons of carbon in the form of carbon dioxide. One square meter rainforest extracts 1-2 kg of carbon from the air. About 40 billion tons of carbon are assimilated per year by microscopic algae floating in the ocean.
However, the vegetation of the Earth is not able to cope with the ever-increasing pollution of the atmosphere, which leads to climate change. Compared to the pre-industrial era, the content of carbon dioxide in the atmosphere has increased by 28%. If measures are not taken to reduce emissions, then by the middle of the 21st century, the average global temperature of the surface atmosphere will increase by 1.5 - 4.5 0С.
This will lead to a redistribution of precipitation, an increase in the number of droughts, and a change in the regime of river flow. The top layer of permafrost, which occupies about 10 million km2 in Russia, will melt. The level of the World Ocean may rise by 20 cm by 2030, which will lead to flooding of coastal areas.
Causes of the greenhouse effect
As early as 1827, the French physicist Joseph Fourier suggested that the earth's atmosphere acts as a kind of glass in a greenhouse: the air lets in the sun's heat, while preventing it from evaporating back into space. And he was right. This effect is achieved due to certain atmospheric gases of secondary importance, such as, for example, water vapor and carbon dioxide. They transmit visible and "near" infrared light emitted by the sun, but absorb "far" infrared radiation, which has a lower frequency and is formed when heated. earth's surface sunbeams. If this did not happen, the Earth would be about 30 degrees colder than it is now, and life on it would practically freeze.
Based on the fact that the "natural" greenhouse effect is a well-established, balanced process, it is quite logical to assume that an increase in the concentration of "greenhouse" gases in the atmosphere should lead to an increase in the greenhouse effect, which in turn will lead to global warming. The amount of CO2 (carbon dioxide) in the atmosphere has been steadily increasing for more than a century due to the widespread use of various types of fossil fuels (coal and oil) as an energy source. In addition, other greenhouse gases, such as methane, nitrous oxide and a range of chlorine-containing substances, are released into the atmosphere as a result of human activity. Although they are produced in smaller quantities, some of these gases are far more dangerous in terms of global warming than carbon dioxide.
Today, few scientists dealing with this problem dispute the fact that human activity leads to an increase in the concentration of greenhouse gases in the atmosphere. According to the Intergovernmental Commission on Climate Change, “an increase in the concentration of greenhouse gases will lead to a heating of the lower layers of the atmosphere and the surface of the earth ... Any change in the Earth’s ability to reflect and absorb heat, including those caused by an increase in the content of greenhouse gases and aerosols in the atmosphere, will lead to change in the temperature of the atmosphere and the world's oceans and disrupt stable patterns of circulation and weather."
However, there is fierce debate about exactly how much of these gases will cause climate warming and to what extent, as well as how soon this will happen. The point is that even when climate change does happen, it's hard to be 100% sure. World average temperatures can fluctuate greatly over several years and decades - and natural causes. The problem is what to consider the average temperature, and on the basis of what criteria to judge whether it really has changed in one direction or another.
In the late 1980s and early 1990s, the average annual global temperature was above normal for several consecutive years. This raised fears that human-caused global warming had already begun. There is a consensus among scientists that over the past hundred years, the average annual global temperature has risen by 0.3 to 0.6 degrees Celsius. However, there is no agreement among them as to what exactly caused this phenomenon. It is difficult to say with certainty whether global warming is happening or not, since the observed increase in temperature is still within the limits of natural temperature fluctuations.
Uncertainty about global warming breeds skepticism about the looming danger. The problem is that when the hypothesis of anthropogenic factors global warming will be confirmed, it will be too late to do anything.
In the last decade, the phrase "greenhouse effect" has practically never left the television screens or from the pages of newspapers. Learning programs in several disciplines at once provide for its thorough study, and almost always it is indicated negative value for the climate of our planet. However, this phenomenon is actually much more multifaceted than it is presented to the layman.
Without the greenhouse effect, life on our planet would be in question
You can start with the fact that the greenhouse effect on our planet has existed throughout its history. Such a phenomenon is simply inevitable for those celestial bodies that, like the Earth, have a stable atmosphere. Without it, for example, the World Ocean would have frozen long ago, and the higher forms of life would not have appeared at all. Scientists have long scientifically proven that if there were no carbon dioxide in our atmosphere, the presence of which is a necessary factor in the process of the greenhouse effect, then the temperature on the planet would fluctuate within -20 0 C, so there would be no talk of the emergence of life at all.
Causes and essence of the greenhouse effect
Answering the question: "What is the greenhouse effect?", First of all, it should be noted that this physical phenomenon got its name by analogy with the processes that occur in the gardeners' greenhouse. Inside it, regardless of the season, it is always a few degrees warmer than in the surrounding space. The thing is that plants absorb visible sunlight, which pass absolutely freely through glass, and through polyethylene, and in general through almost any obstacle. After that, the plants themselves also begin to radiate energy, but already in the infrared range, the rays of which can no longer freely overcome the same glass, so a greenhouse effect occurs. The reasons for this phenomenon, therefore, lie precisely in the imbalance between the spectrum of visible sun rays and those radiations that plants and other objects give off to the external environment.
The physical basis of the greenhouse effect
As for our planet as a whole, the greenhouse effect here arises due to the presence of a stable atmosphere. To maintain its temperature balance, the Earth must give off as much energy as it receives from the Sun. However, the presence of carbon dioxide and water in the atmosphere, which absorb infrared rays, thus acting as glass in a greenhouse, causes the formation of so-called greenhouse gases, some of which returns back to the Earth. These gases create a "quilt effect", raising the temperature near the surface of the planet.
Greenhouse effect on Venus
From the foregoing, we can conclude that the greenhouse effect is characteristic not only for the Earth, but also for all planets and other celestial bodies with a stable atmosphere. Indeed, studies conducted by scientists have shown that, for example, near the surface of Venus this phenomenon has a much more pronounced character, which is due, first of all, to the fact that its air envelope Almost 100% is made up of carbon dioxide.
the greenhouse effect- this 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 such irreversible consequences as climate change and global warming. Several centuries ago this ecological problem existed, but was not so obvious. With the development of technology, the number of sources that provide the greenhouse effect in the atmosphere is increasing every year.
Causes of the greenhouse effect
the use of combustible minerals in industry - coal, oil, natural gas, the combustion of which releases a huge amount 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 absorb carbon dioxide and release 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 an increase in demand food, clothing, housing, and to ensure this, industrial production is growing, which is increasingly polluting the air with greenhouse gases;
agrochemicals and fertilizers contain varying amounts of compounds that release nitrogen, one of the greenhouse gases, as a result of evaporation;
the decomposition and burning of garbage in landfills contribute to the increase in greenhouse gases.
The impact of the greenhouse effect on climate
Considering the results of the greenhouse effect, it can be determined that the main one is climate change. Since the air temperature rises every year, the waters of the seas and oceans evaporate more intensively. Some scientists predict that in 200 years such a phenomenon as the "drying" of the oceans, namely a significant decrease in water levels, will become noticeable. This is one side of the problem. The other is that the increase in temperature leads to the melting of glaciers, which contributes to the rise in the water level of 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. Here, crops are dying, which leads to a food crisis for the population of the area. Also, there is no food for animals, because plants die out due to lack of water.
First of all, we need to stop deforestation, plant new trees and shrubs, as they absorb carbon dioxide and produce oxygen. Using electric vehicles will reduce the amount of exhaust gases. In addition, you can change from cars to bicycles, which is more convenient, cheaper and safer for the environment. Alternative fuels are also being developed, which, unfortunately, is slowly being introduced into our daily lives.
19. Ozone layer: value, composition, possible causes of its destruction, protection measures taken.
Earth's ozone layer Ozone is a region of the Earth's atmosphere where ozone is produced, 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 great 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 assigned to it. The processes of formation and destruction of the ozone layer were strictly balanced until man appeared on the planet and in his development did not reach the current technical level.
In the 70s. of the twentieth century, it was proved that many substances actively used by man in economic activities can significantly reduce the level of ozone in Earth's atmosphere.
Substances that deplete 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 aviation flights and rocket launches, i.e. substances whose molecules contain chlorine or bromine.
These substances, released into the atmosphere near the Earth's surface, reach the upper limit in 10–20 years. the boundaries of the ozone layer. There, under the influence of ultraviolet radiation, they decompose, forming chlorine and bromine, which, in turn, interacting with stratospheric ozone, significantly reduce its amount.
Causes of destruction and depletion of the ozone layer of the Earth.
Let us consider once again in more detail the causes of 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.
The mechanism of the greenhouse effect is as follows. The sun's rays, reaching the Earth, are absorbed by the soil surface, vegetation, water surface, etc. The heated surfaces give off thermal energy again to the atmosphere, but in the form of long-wave radiation.
Atmospheric gases (oxygen, nitrogen, argon) do not absorb thermal radiation from the earth's surface, but scatter it. However, as a result of burning fossil fuels and other production processes accumulate in the atmosphere: carbon dioxide, carbon monoxide, various hydrocarbons (methane, ethane, propane, etc.), which do not scatter, but absorb thermal radiation coming from the Earth's surface. The screen that arises in this way leads to the appearance of the greenhouse effect - global warming.
In addition to the greenhouse effect, the presence of these gases causes the formation of the so-called photochemical smog. At the same time, as a result of photochemical reactions, hydrocarbons form very toxic products - aldehydes and ketones.
Global warming is one of the most significant consequences of anthropogenic pollution of the biosphere. It manifests itself both in climate change and in biota: the production process in ecosystems, the shift in the boundaries of plant formations, and changes in crop yields. Especially strong changes can affect high and middle latitudes. According to forecasts, it is here that the temperature of the atmosphere will increase most noticeably. The nature of these regions is especially susceptible to various impacts and is extremely slowly restored.
As a result of warming, the taiga zone will shift to the north by about 100-200 km. The rise in the ocean level due to warming (melting of ice and glaciers) can be up to 0.2 m, which will lead to the flooding of the mouths of large, especially Siberian, rivers.
The regular conference of the countries-participants of the Convention on Prevention of Climate Change, held in Rome in 1996, once again confirmed the need for coordinated international action to solve this problem. In accordance with the Convention, industrialized countries and countries with economies in transition have assumed obligations to stabilize the production of greenhouse gases. The countries of the European Union have included in their national programs provisions to reduce carbon emissions by 20% by 2005.
In 1997, the Kyoto (Japan) agreement was signed, under which developed countries pledged to stabilize greenhouse gas emissions at the 1990 level by 2000.
However, greenhouse gas emissions have even increased since then. This was facilitated by the US withdrawal from the Kyoto agreement of 2001. Thus, the implementation of this agreement was threatened with disruption, since the quota necessary for the entry into force of this agreement was violated.
In Russia, due to the general decline in production, greenhouse gas emissions in 2000 amounted to 80% of the 1990 level. Therefore, in 2004 Russia ratified the Kyoto agreement, giving it a legal status. Now (2012) this agreement is in force, other states (for example, Australia) join it, but the decisions of the Kyoto Agreement remain unfulfilled. However, the struggle to implement the Kyoto agreement continues.
One of the most famous fighters against global warming is the former Vice President of the United States. A. Gore. After losing the 2000 presidential election, he dedicates himself to combating global warming. "Save the world before it's too late!" is its slogan. Armed with a set of slides, he traveled the world explaining the science and politics of global warming, the potential for serious consequences in the near future, if not limited by the rise in human-caused carbon dioxide emissions.
A. Gore wrote a widely known book “Inconvenient truth. Global warming, how to stop a planetary catastrophe. In it, he confidently and rightly writes: “Sometimes it seems that our climate crisis is proceeding slowly, but in fact it is happening very quickly, becoming a truly planetary danger. And in order to defeat the threat, we must first recognize the fact of its existence. Why don't our leaders seem to hear such loud warnings of danger? They resist the truth, because at the moment of recognition they will face their moral duty - to act. Is it just much more convenient to ignore the danger warning? Perhaps, but an inconvenient truth does not disappear just because it is not seen.
In 2006, he was awarded the American Literary Prize for the book. Based on the book was created documentary « The Inconvenient Truth" with A. Gore in the title role. The film in 2007 received an Oscar and was included in the rubric "Everyone Should Know This". In the same year, A. Gore (together with the IPCC expert group) was awarded Nobel Prize world for their work in environmental protection and research on climate change.
Currently, A. Gore is also actively continuing the fight against global warming, being a freelance consultant to the Intergovernmental Panel on Climate Change (IPCC), established by the World Meteorological Organization (WMO) and the United Nations Program for environment(UNEP).
Global warming and greenhouse effect
Back in 1827, the French physicist J. Fourier suggested that the Earth's atmosphere acts as a glass in a greenhouse: air lets in solar heat, but does not allow it to evaporate back into space. And he was right. This effect is achieved due to some atmospheric gases, such as water vapor and carbon dioxide. They transmit visible and "near" infrared light emitted by the Sun, but absorb "far" infrared radiation, which is formed when the earth's surface is heated by the sun's rays and has a lower frequency (Fig. 12).
In 1909, the Swedish chemist S. Arrhenius for the first time emphasized the enormous role of carbon dioxide as a temperature regulator of the near-surface air layers. Carbon dioxide freely transmits the sun's rays to the earth's surface, but absorbs most of the thermal radiation of the earth. This is a kind of colossal screen that prevents the cooling of our planet.
The temperature of the Earth's surface is steadily increasing, having increased over the XX century. by 0.6 °C. In 1969 it was 13.99°C, in 2000 it was 14.43°C. Thus, the average temperature of the Earth at present is about 15 °C. At a given temperature, the surface of the planet and the atmosphere are in thermal equilibrium. Heated by the energy of the Sun and the infrared radiation of the atmosphere, the surface of the Earth returns an average equivalent amount of energy to the atmosphere. This is the energy of evaporation, convection, heat conduction and infrared radiation.
Rice. 12. Schematic representation of the greenhouse effect due to the presence of carbon dioxide in the atmosphere
Recently, human activity has introduced an imbalance in the ratio of absorbed and released energy. Before human intervention in global processes on the planet, the changes taking place on its surface and in the atmosphere were associated with the content of gases in nature, which, with the light hand of scientists, were called "greenhouse". These gases include carbon dioxide, methane, nitric oxide and water vapor (Fig. 13). Now anthropogenic chlorofluorocarbons (CFCs) have been added to them. Without the gas "blanket" enveloping the Earth, the temperature on its surface would be 30-40 degrees lower. The existence of living organisms in this case would be very problematic.
Greenhouse gases temporarily trap heat in our atmosphere, creating the so-called greenhouse effect. As a result of man-made human activities, some greenhouse gases increase their share in the overall balance of the atmosphere. This applies primarily to carbon dioxide, the content of which has been steadily increasing from decade to decade. Carbon dioxide creates 50% of the greenhouse effect, CFCs account for 15-20%, and methane accounts for 18%.
Rice. 13. The proportion of anthropogenic gases in the atmosphere with the greenhouse effect of nitrogen 6%
In the first half of the XX century. the content of carbon dioxide in the atmosphere was estimated at 0.03%. In 1956, as part of the first International Geophysical Year, scientists held special studies. The given figure was adjusted and amounted to 0.028%. In 1985, measurements were taken again, and it turned out that the amount of carbon dioxide in the atmosphere had increased to 0.034%. Thus, an increase in the content of carbon dioxide in the atmosphere is a proven fact.
Over the past 200 years, as a result of anthropogenic activities, the content of carbon monoxide in the atmosphere has increased by 25%. This is due, on the one hand, to the intensive combustion of fossil fuels: gas, oil, shale, coal, etc., and on the other hand, to the annual decrease in forest areas, which are the main sinks of carbon dioxide. In addition, the development of such industries Agriculture, as rice growing and animal husbandry, as well as the growth of urban landfill areas, lead to an increase in the emission of methane, nitrogen oxide and some other gases.
Methane is the second most important greenhouse gas. Its content in the atmosphere increases by 1% annually. The most significant methane suppliers are landfills, large cattle, rice fields. Gas reserves in the landfills of large cities can be considered as small gas fields. As for rice fields, despite the large release of methane, it turned out that relatively little of it enters the atmosphere, since most of it is broken down by bacteria associated with the rice root system. Thus, the impact of rice agricultural ecosystems on the release of methane into the atmosphere is generally moderate.
Today there is no doubt that the trend towards the use of predominantly fossil fuels inevitably leads to global catastrophic climate change. At the current rate of use of coal and oil in the next 50 years, an increase in the average annual temperature on the planet is predicted in the range from 1.5 ° C (near the equator) to 5 ° C (in high latitudes).
An increase in temperature as a result of the greenhouse effect threatens with unprecedented environmental, economic and social consequences. The water level in the oceans can rise by 1-2 m due to sea water and melting polar ice. (Due to the greenhouse effect, the level of the World Ocean in the 20th century has already risen by 10-20 cm.) It has been established that a 1 mm rise in sea level leads to a retreat of the coastline by 1.5 m.
If the sea level rises by about 1 m (and this is the worst scenario), then by 2100 about 1% of the territory of Egypt, 6% of the territory of the Netherlands, 17.5% of the territory of Bangladesh and 80% of the Majuro Atoll, which is part of the Marshal, will be under water - fishing islands. This will be the beginning of a tragedy for 46 million people. According to the most pessimistic forecasts, the rise in the level of the World Ocean in the XXI century. may entail the disappearance from the world map of countries such as Holland, Pakistan and Israel, the flooding of most of Japan and some other island states. St. Petersburg, New York and Washington may go under water. While some parts of the land are at risk of being at the bottom of the sea, others will suffer from the most severe drought. Disappearance threatens the Azov and Aral seas and many rivers. The area of deserts will increase.
A group of Swedish climatologists found that from 1978 to 1995 the area of floating ice in the Arctic Ocean decreased by about 610 thousand km2, i.e. by 5.7%. At the same time, it turned out that through the Fram Strait, which separates the Svalbard (Svalbard) archipelago from Greenland, up to 2600 km 3 of floating ice is annually carried into the open Atlantic at an average speed of about 15 cm / s (which is about 15-20 times more than the flow of such a river as Congo).
In July 2002, a call for help was heard from the small island state of Tuvalu, located on nine atolls in the South Pacific Ocean (26 km 2, 11.5 thousand inhabitants). Tuvalu is slowly but surely submerged - the highest point in the state rises only 5 m above sea level. time to raise the sea level in the area by more than 3 m, due to rising ocean levels due to global warming. If this trend continues, the tiny state will be washed off the face of the Earth. The government of Tuvalu is taking measures to resettle citizens in the neighboring state of Niue.
An increase in temperature will cause a decrease in soil moisture in many regions of the Earth. Droughts and typhoons will become commonplace. The ice cover of the Arctic will be reduced by 15%. In the coming century, the ice cover of rivers and lakes in the Northern Hemisphere will be 2 weeks less than in the 20th century. Ice melts in the mountains South America, Africa, China and Tibet.
Global warming will also affect the state of the world's forests. Forest vegetation, as is known, can exist within very narrow limits of temperature and humidity. Most of it may perish, the complex ecological system will be at the stage of destruction, and this will entail a catastrophic decrease in the genetic diversity of plants. As a result of global warming on Earth in the second half of the XXI century. may disappear from a quarter to half of the species of land flora and fauna. Even under the most favorable conditions, by the middle of the century, the immediate threat of extinction will hang over almost 10% of the species of land animals and plants.
Research has shown that in order to avoid global catastrophe, it is necessary to reduce carbon emissions to the atmosphere to 2 billion tons per year (one third of the current volume). Given the natural population growth, by 2030-2050. per capita should be no more than 1/8 of the amount of carbon emitted today on average per inhabitant of Europe.
MINISTRY OF EDUCATION OF THE REPUBLIC OF BELARUS
EE "BELARUSIAN STATE ECONOMIC UNIVERSITY"
ESSAY
by discipline: Fundamentals of ecology and energy saving
on the topic: Greenhouse effect: causes and consequences
Checked by: T.N. Filipović
HISTORICAL INFORMATION
The idea of the mechanism of the greenhouse effect was first stated in 1827 by Joseph Fourier in the article "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 as factors affecting the overall heat balance of the Earth ( heating by solar radiation, cooling due to radiation, internal heat of the Earth), as well as factors affecting 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 blackened from the inside, covered with glass. De Saussure measured the temperature difference inside and outside such a vessel, set on a straight line. 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 inflow of cool air from the outside) and the different transparency of the glass in the visible and infrared ranges.
It is the latter factor that received the name of the greenhouse effect in later literature - by 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 the transparency in the optical range.
CAUSES OF THE GREENHOUSE EFFECT
The ever-increasing volumes of fuel burned, the penetration of industrial gases into the atmosphere, widespread burning and deforestation, anaerobic fermentation and much more - all this led to the emergence of such a global environmental problem like the greenhouse effect.
Main chemicals The following five gases are responsible for the greenhouse effect:
Carbon dioxide (50% greenhouse effect);
Chlorofluorocarbons (25%);
Nitric oxide (8%);
Ground level ozone (7%);
Methane (10%).
Carbon dioxide released into the atmosphere as a result of burning various kinds fuel. About 1/3 of the amount of carbon dioxide is due to burning and deforestation, as well as desertification processes. The reduction of forests means a reduction in the number of green woody plants that can absorb carbon dioxide through the process of photosynthesis. Every year, the content of carbon dioxide in the Earth's atmosphere increases by an average of 0.5%.
Chlorofluorocarbons contribute about 25% to the total greenhouse effect. They have a double danger for humans and the nature of the Earth: firstly, they contribute to the development of the greenhouse effect; secondly, they destroy atmospheric ozone.
Methane - one of the important "greenhouse" gases. The content of methane in the atmosphere has doubled over the past 100 years. The main source of methane in the Earth's atmosphere is the natural process of anaerobic fermentation that takes place in wet rice production, in animal husbandry, in wastewater treatment fields, in the decomposition of urban and municipal wastewater, in the processes of decay and decomposition. organic matter in dumps of household garbage, etc. Oil pollution of the land surface and the World Ocean also makes a significant contribution to the increase in free methane in the atmosphere of our planet.
Nitric oxide is formed in many technological processes of modern agricultural production (for example, in the formation and use of organic fertilizers), as well as as a result of the combustion of ever-increasing volumes of various fuels.
POSSIBLE SCENARIOS FOR GLOBAL CLIMATE CHANGE
Global climate change is very complex, so modern science cannot give an unambiguous answer about what awaits us in the near future. There are many scenarios for the development of the situation. To determine these scenarios, factors slowing down and accelerating global warming are taken into account.
Factors accelerating global warming:
Emissions of CO 2 , methane, nitrous oxide as a result of man-made activities;
Decomposition, due to temperature increase, of geochemical sources of carbonates with the release of CO 2 . AT earth's crust contained in the bound state of carbon dioxide 50,000 times more than in the atmosphere;
An increase in the content of water vapor in the Earth's atmosphere, due to an increase in temperature, and hence the evaporation of ocean water;
Emission of CO 2 by the World Ocean due to its heating (the solubility of gases decreases with increasing water temperature). For each degree increase in water temperature, the solubility of CO2 in it drops by 3%. The World Ocean contains 60 times more CO 2 than the Earth's atmosphere (140 trillion tons);
Decrease in the Earth's albedo (the reflectivity of the planet's surface) due to the melting of glaciers, changes in climatic zones and vegetation. The sea surface reflects much less sunlight than the polar glaciers and snows of the planet, mountains devoid of glaciers also have a lower albedo, woody vegetation moving north has a lower albedo than tundra plants. Over the past five years, the Earth's albedo has already decreased by 2.5%;
Emission of methane during thawing of permafrost;
Decomposition of methane hydrates - crystalline icy compounds of water and methane contained in the subpolar regions of the Earth.
Factors slowing down global warming:
Global warming causes ocean currents to slow down, slowing of the warm Gulf Stream will cause a decrease in temperature in the Arctic;
With an increase in temperature on Earth, evaporation increases, and hence cloudiness, which is a certain kind of barrier to the path of sunlight. Cloud area increases by approximately 0.4% for every degree of warming;
With the growth of evaporation, the amount of precipitation increases, which contributes to the waterlogging of lands, and swamps are known to be one of the main depots of CO 2 ;
An increase in temperature will contribute to the expansion of the area of warm seas, and hence the expansion of the range of mollusks and coral reefs, these organisms are actively involved in the deposition of CO 2, which goes to the construction of shells;
An increase in the concentration of CO 2 in the atmosphere stimulates the growth and development of plants, which are active acceptors (consumers) of this greenhouse gas.
Here are 5 scenarios for the future of planet Earth:
Scenario 1 - global warming will occur gradually. The earth is a very large and complex system consisting of a large number interconnected structural components. The planet has a mobile atmosphere, the movement of air masses of which distributes thermal energy across the latitudes of the planet, the Earth has a huge accumulator of heat and gases - the World Ocean (the ocean accumulates 1000 times more heat than the atmosphere) Changes in such a complex system cannot occur quickly. Centuries and millennia will pass before any tangible climate change can be judged.
Scenario 2 - global warming will occur relatively quickly. The most "popular" scenario at present. According to various estimates, over the past hundred years, the average temperature on our planet has increased by 0.5-1 ° C, the concentration of CO 2 has increased by 20-24%, and methane by 100%. In the future, these processes will continue and by the end of the 21st century, the average temperature of the Earth's surface may increase from 1.1 to 6.4°C. Further melting of the Arctic and Antarctic ice can accelerate the processes of global warming due to changes in the planet's albedo. According to some scientists, only the planet's ice caps, due to the reflection of solar radiation, cool our Earth by 2 ° C, and the ice covering the surface of the ocean significantly slows down the heat exchange processes between the relatively warm ocean waters and the colder surface layer of the atmosphere. In addition, over the ice caps, there is practically no main greenhouse gas - water vapor, since it is frozen out.
Global warming will be accompanied by rising sea levels. From 1995 to 2005, the level of the World Ocean has already risen by 4 cm, instead of the predicted 2 cm. If the level of the World Ocean continues to rise at the same rate, then by the end of the 21st century, the total rise in its level will be 30 - 50 cm, which will cause partial flooding of many coastal areas, especially the densely populated coast of Asia. It should be remembered that about 100 million people on Earth live at an altitude of less than 88 centimeters above sea level.
In addition to rising sea levels, global warming affects the strength of the winds and the distribution of precipitation on the planet. As a result, the frequency and scale of various natural disasters (storms, hurricanes, droughts, floods) will increase on the planet.
Currently, 2% of all land suffers from drought, according to some scientists, by 2050, up to 10% of all continents will be covered by drought. In addition, the seasonal distribution of precipitation will change.
AT Northern Europe and in the western United States, the amount of precipitation and the frequency of storms will increase, hurricanes will rage 2 times more often than in the 20th century. Climate Central Europe will become changeable, in the heart of Europe winters will become warmer and summers rainier. Eastern and Southern Europe, including the Mediterranean, will face drought and heat.
