Greenhouse effect. What are greenhouse gases

Greenhouse gases - gaseous components of the atmosphere of natural or anthropogenic origin, which absorb and re-emit infrared radiation.

Anthropogenic increase in the concentration of greenhouse gases in the atmosphere leads to an increase in surface temperature and climate change.
The list of greenhouse gases subject to limitation under the UN Framework Convention on Climate Change (1992) is defined in Annex "A" to the Kyoto Protocol (signed in Kyoto (Japan) in December 1997 by 159 states) and includes carbon dioxide (CO2) and methane ( CH4), nitrous oxide (N2O), perfluorocarbons (PFCs), hydrofluorocarbons (HFCs) and sulfur hexafluoride (SF6).

water vapor- the most common greenhouse gas - is excluded from this consideration, since there is no evidence of an increase in its concentration in the atmosphere (that is, the danger associated with it is not visible).

Carbon dioxide ( carbon dioxide) (CO2)- the most important source of climate change, accounting for, according to estimates, about 64% global warming.

The main sources of carbon dioxide emissions into the atmosphere are the production, transportation, processing and consumption of fossil fuels (86%), the reduction rainforest and other biomass combustion (12%), and other sources (2%), such as cement production and carbon monoxide oxidation. Once released, the carbon dioxide molecule cycles through the atmosphere and biota and is finally taken up by oceanic processes or through long-term accumulation in terrestrial biological storage (i.e. taken up by plants). The amount of time that approximately 63% of the gas is removed from the atmosphere is called the effective residence time. The estimated effective residence time for carbon dioxide ranges from 50 to 200 years.
Methane (CH4) has both natural and anthropogenic origin. In the latter case, it is formed as a result of fuel production, digestive fermentation (for example, in livestock), rice cultivation, deforestation (mainly due to the burning of biomass and the decay of excess organic matter). Methane accounts for an estimated 20% of global warming. Methane emissions are a significant source of greenhouse gases.

Nitrous oxide (N2O)- the third most important greenhouse gas of the Kyoto Protocol. It is emitted during the production and use of mineral fertilizers, in chemical industry, in agriculture, etc. It accounts for about 6% of global warming.

Perfluorocarbons- PFCs (Perfluorocarbons - PFCs). Hydrocarbon compounds in which fluorine partially replaces carbon. The main sources of these gases are the production of aluminum, electronics and solvents. During aluminum smelting, PFC emissions occur in an electric arc or in so-called "anodic effects".

Hydrofluorocarbons (HFCs)- hydrocarbon compounds in which halogens partially replace hydrogen. Gases designed to replace ozone-depleting substances have exceptionally high GWPs (140 11700).

Sulfur hexafluoride (SF6)- greenhouse gas, used as an electrical insulating material in the electric power industry. Emissions occur during its production and use. It remains in the atmosphere for an extremely long time and is an active absorber of infrared radiation. Therefore, this compound, even with relatively small emissions, has the potential to influence the climate for a long time in the future.

Greenhouse effect from different gases can be reduced to a common denominator, expressing how much 1 ton of a particular gas gives a greater effect than 1 ton of CO2. For methane, the conversion factor is 21; for nitrous oxide, 310; and for some fluorinated gases, several thousand.

1. Increasing the efficiency of energy use in the relevant sectors of the national economy;
2. Protection and improvement of the quality of sinks and accumulators of greenhouse gases, taking into account their obligations under the relevant international environmental agreements; assistance rational methods sustainable forest management, afforestation and reforestation;
3. Encourage sustainable forms Agriculture in light of climate change considerations;
4. Facilitate implementation, conduct research work, development and increased use of new and renewable forms of energy, carbon dioxide absorption technologies and innovative environmentally friendly technologies;
5. Gradual reduction or elimination of market distortions, fiscal incentives, exemptions from taxes and duties, and subsidies contrary to the purpose of the Convention in all sectors that emit greenhouse gases, and the use of market-based instruments;
6. Promoting appropriate reforms in relevant sectors to promote the implementation of policies and measures that limit or reduce greenhouse gas emissions;
7. Measures to limit and/or reduce greenhouse gas emissions from transport;
Control and/or reduction of methane emissions through recovery and use in waste disposal, as well as in the production, transportation and distribution of energy.

These provisions of the Protocol are of a general nature and provide the Parties with the opportunity to independently choose and implement the set of policies and measures that will best suit national circumstances and priorities.
The main source of greenhouse gas emissions in Russia is the energy sector, which accounts for more than 1/3 of total emissions. The second place is occupied by the extraction of coal, oil and gas (16%), the third - industry and construction (about 13%).

Thus, the greatest contribution to reducing greenhouse gas emissions in Russia can be made by realizing the huge potential for energy savings. At present, the energy intensity of the Russian economy exceeds the world average by 2.3 times, and the average for EU countries by 3.2 times. The potential for energy savings in Russia is estimated at 39-47% of current energy consumption, and it is mainly in the production of electricity, transmission and distribution of thermal energy, industries and unproductive energy losses in buildings.

The material was prepared on the basis of information from open sources

1.2.1 Greenhouse gases

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and re-emit infrared radiation.

Accumulator - components of the climate system in which greenhouse gases accumulate.

Sink - any process, activity or mechanism that absorbs greenhouse gases.

Source - any process, type of activity, as a result of which greenhouse gases enter the atmosphere.

Carbon dioxide - carbon dioxide, is constantly formed in nature during oxidation organic matter: decay of plant and animal remains, respiration. Its main source is anthropogenic processes: combustion of fossil fuels (coal, gas, oil and products of its processing, oil shale, firewood). All these substances are mainly composed of carbon and hydrogen. Therefore, they are also called organic, hydrocarbon fuels. Due to their combustion, up to 80% of carbon dioxide enters the atmosphere.

When burning, as you know, oxygen is absorbed and carbon dioxide is released. As a result of this process, every year humanity releases 7 billion tons of carbon dioxide into the atmosphere. At the same time, forests are cut down on Earth - one of the main consumers of carbon dioxide, moreover, they are cut down at a rate of 12 hectares per minute. So it turns out that more and more carbon dioxide enters the atmosphere, and less and less is consumed by plants.

Reasons for the increase in the content of CO 2 in the atmosphere:

1. burning fossil fuels;

2. deforestation;

3. agriculture;

4. overgrazing and a number of other violations.

The carbon dioxide cycle on Earth is disrupted, so in last years Atmospheric carbon dioxide is not only increasing, but the growth rate is also increasing. And the more it is, the stronger the greenhouse effect.

Next in terms of contribution to the greenhouse effect are methane CH 4 and nitrous oxide N 2 O. The concentration of both gases is determined by both natural and anthropogenic causes.

So, a natural source of CH 4 is waterlogged soils in which anaerobic decomposition processes occur. Methane is also called swamp gas. In considerable quantities, it is also supplied by vast mangroves in the tropics. It enters the atmosphere and from tectonic faults and cracks during earthquakes. Anthropogenic emissions of methane are also large. Natural and anthropogenic emissions are estimated to be around 70% and 30%, but the latter are growing rapidly.

At an altitude of 15-20 km, under the action of sunlight, it decomposes into hydrogen and carbon, which, when combined with oxygen, forms CO 2.

There is an assumption that methane is the main cause of warming. In particular, Doctor of Geological and Mineralogical Sciences N.A. Yasamanov, suggest that methane is mainly "guilty" of the current global warming. Also, the concentration of methane increases in the process of intensification of agricultural activities.

Natural sources of N2O to the atmosphere include the ocean and soils. The anthropogenic additive is associated with the combustion of fuel and biomass, the leaching of nitrogen fertilizers.

The intensity of N 2 O release has been rapidly increasing lately (from 0.1% to 1.3% per year). This growth is mainly due to more wide application mineral fertilizers. The lifetime of N 2 O is long - 170 years.

The share of global warming impact of each gas is shown in Table 1.

Table 1. Main greenhouse gases, their sources and contribution to global warming (data from 2000) .

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When fossil fuels (coal, oil, gas) are burned, carbon dioxide and other gases are released into the atmosphere. These emissions contribute to an increase in the temperature on Earth (“greenhouse effect”). Rising temperatures are causing sea levels to rise, powerful hurricanes and other climate-related problems. If everyone on the planet uses cars less, saves energy and creates less waste, humanity will reduce its carbon footprint, which will help in the fight against global warming.

Steps

carbon footprint

Calculate your carbon footprint. A carbon footprint is the amount of carbon that is released into the atmosphere through the activities of a particular person. If your life is based on in large numbers fuel burned, then your footprint is quite large. For example, the "footprint" of a person who uses a bicycle is smaller than the "footprint" of a person who rides a car.

If you're worried about reducing your greenhouse gas emissions, change your habits. Focus on those aspects of your life that you can change (preferably forever). Even small lifestyle changes can have importance for ecology.

Remember that lifestyle changes are only the first step. If you want to fight greenhouse gas emissions on a global level, you need to take action to force multinational corporations to reduce emissions. Studies show that only 90 companies are responsible for two-thirds of greenhouse gas emissions. Looking for ways global struggle with greenhouse effect.

One of the main greenhouse gases is carbon dioxide - carbon dioxide (CO2). Until recently, its role was too emphasized; up to half of the total contribution to the greenhouse effect was attributed to its share. However, it is now believed that this estimate was overestimated.

It has been instrumentally proven that recent decades the annual accumulation of CO 2 in the atmosphere is 0.4%. Since the beginning of the XX century. the level of CO 2 in the atmosphere increased by 31%. This value is essential to raise the temperature. According to the most optimistic scenario, the temperature will increase by 1.5-2°C in the next century, but the most pessimistic one - by almost 6°C.

Every year, 6 billion tons of carbon dioxide enter the atmosphere from anthropogenic sources, of which 3 billion tons are absorbed by vegetation during photosynthesis, the remaining 3 billion tons accumulate. The total amount of accumulation due to the fault of man over the past 100 years amounted to about 170 billion tons. The given data should be considered in comparison with 190 billion tons of carbon dioxide that annually enter the atmosphere due to natural processes. According to a number of Russian scientists, the contribution of anthropogenic activity to global warming is only 10-15%, and the rest is accounted for by global natural cycles. Therefore, the efforts of mankind towards reducing greenhouse gas emissions will hardly be able to noticeably slow down the coming warming.

An increase in the concentration of CO 2 does not mean death for the biosphere. Millions of years ago, during the Carboniferous period, the concentration of CO 2 was 10 times higher than now. During that period, the vegetation flourished, the trees reached large sizes. But for the human population, the conditions were unfavorable. Ultimate upper level The content of CO 2 in the atmosphere for humans has not been established.

There are different hypotheses about the reasons for the accumulation of CO 2 in the atmosphere. According to the first, most common point of view, carbon dioxide accumulates in the atmosphere as a product of fossil fuel combustion. The second hypothesis considers the disturbance of the functions of microbial communities in the soils of Siberia and part of North America. Regardless of the choice of hypothesis, the accumulation of carbon dioxide occurs on an ever-increasing scale.

Greenhouse gases such as methane, nitrogen oxides and water vapor have a major impact on the climate.

Until recently underestimated the role of methane(CH 4). It is actively involved in the greenhouse effect. In addition, rising to a height of 15-20 km, methane under the action of sunlight decomposes into hydrogen and carbon, which combines with oxygen to form carbon dioxide. This further enhances the greenhouse effect.

In nature, CH 4 is formed in swamps during the decay of organic matter, it is also called swamp gas. Methane also occurs in extensive mangroves in tropical areas. The increase in the concentration of CH 4 occurs in the world due to the destruction of biota. In addition, it enters the atmosphere from tectonic faults on land and at the bottom of the ocean.

Anthropogenic methane emissions are associated with the exploration and production of minerals, with the combustion of mineral fuels in thermal power plants and fossil fuels in internal combustion engines Vehicle, its isolation on livestock farms. Use of nitrogen fertilizers, rice cultivation, landfills household waste, leaks and incomplete combustion of natural gas also lead to increased emissions of methane and nitrogen oxides, which are powerful greenhouse gases. The content of CH 4 in the atmosphere, according to instrumental data, increases by 1% per year. Over the past 100 years, growth has been 145%.

nitrogen oxides accumulate in the atmosphere per year within 0.2%, and the total accumulation during the period of intense industrial development was about 15%. The increase in the content of nitrogen oxides is due to agricultural activities and massive destruction of forests.

The rapid warming of the climate on Earth leads to an acceleration of the water cycle in nature, increased evaporation from water surfaces, which contributes to the accumulation water vapor in the atmosphere and activation greenhouse effect. According to some scientists, about 60% of the greenhouse effect is caused by water vapor. The more of them in the troposphere, the stronger the greenhouse effect, and their concentration, in turn, depends on surface temperatures and water surface area.

Human industrial activity entails harmful effects on the atmosphere. This factor has already become a commonplace and only experts in the environmental sphere pay attention to it. Meanwhile, harmful emissions pose ever more acute questions for organizations involved in global changes climate. In the list of the most pressing problems at conferences devoted to ecology, greenhouse gas regularly appears as one of the most dangerous factors influencing the atmosphere and biota. The fact is that gaseous compounds of this type cannot transmit thermal radiation, which contributes to the heating of the atmosphere. There are several sources of formation of such gases, among which are biological phenomena. And now it is worth familiarizing yourself with the composition of greenhouse mixtures in more detail.

Water vapor as the main greenhouse gas

Gases of this type form about 60% of the total volume of substances due to which it is created. As the temperature of the Earth rises, evaporation and the total concentration in the atmosphere also increase. At the same time, the previous level of humidity is maintained, which contributes to the greenhouse effect. The natural essence possessed by the greenhouse gas in the form of vapor undoubtedly has positive aspects in the matter of natural regulation of the atmospheric composition. But there are also negative consequences of this process. The fact is that against the background of increasing humidity, there is also an increase in the cloud mass, which reflects the direct rays of the sun. As a result, there is already an anti-greenhouse effect, in which the intensity of thermal radiation and, accordingly, the heating of the atmosphere decreases.

Carbon dioxide

Among the main sources of emissions of this type are volcanic eruptions, human activities and processes occurring in the biosphere. Anthropogenic sources include the combustion of fuel materials and biomass, industrial processes and other factors leading to the formation of carbon dioxide. This is the same greenhouse gas that is actively involved in the processes of biocenosis. It is also the most durable in terms of staying in the atmosphere. According to some reports, further accumulation of carbon dioxide in the atmospheric layers is limited by the risk of consequences not only for the balance in the biosphere, but also for the existence of human civilization as a whole. It is these ideas that are the main motivation for developing measures to counteract the greenhouse effect.

Methane

Remains in the atmosphere for about 10 years. Previously, it was believed that the effect of methane on the stimulation of the greenhouse effect is 25 times greater than carbon dioxide. But the last Scientific research gave even more pessimistic results - it turned out that the potential for exposure to this gas was underestimated. However, the situation is mitigated by a short period during which the atmosphere retains methane. This type of greenhouse gas comes from anthropogenic activities. It can be rice growing, digestive fermentation, mixing forest areas etc. According to some studies, an intensive increase in methane concentration took place in the first millennium of our era. Such phenomena were associated precisely with the expansion of cattle breeding and agricultural production, as well as with the burning of forests. In subsequent centuries, the level of methane concentration decreased, although today the opposite trend is observed.

Ozone

The composition of greenhouse gaseous mixtures contains not only components that are dangerous from the point of view, but also beneficial parts. These include ozone, which protects the Earth from ultraviolet light. However, not everything is clear-cut here either. Scientists divide this gas into two categories - tropospheric and stratospheric. As for the former, it can be dangerous due to its toxicity. At the same time, the increased content of tropospheric elements contributes to the growth of the greenhouse effect. At the same time, the stratospheric layer acts as the main protection against the effects harmful radiation. In regions where this type of greenhouse gas has an increased concentration, strong effects on vegetation are observed, which manifest themselves in the inhibition of photosynthetic potential.

Countering the greenhouse effect

There are several areas in which work is underway on methods to contain this process. Among the main measures, the use of tools for regulating the interaction between storages and sinks of greenhouse gases stands out. In particular, environmental agreements at the local level contribute to the active development of forestry. It is also worth noting the reforestation measures, which will minimize the greenhouse effect in the future. Gas emitted into the atmosphere from industries is also amenable to reduction in many industries. For this, measures are being introduced to limit emissions in transport, in production areas, at power plants, etc. For this purpose, alternative methods of fuel processing and gas removal systems are being developed. For example, in recent times a recovery system is being actively introduced, thanks to which enterprises optimize the processes of removing their waste.

Conclusion

In the processes of formation of the greenhouse effect, human activity does not play the most big role. This can be seen from the proportion of gas volumes that are produced by anthropogenic sources. However, it is these harmful emissions that are the most dangerous for the atmosphere. That's why environmental organizations consider greenhouse gas as a factor in negative climate change. As a result, means are used to curb the spread and accumulation of harmful substances that increase the risk of global warming. Moreover, the fight against harmful emissions is carried out in various directions. This applies not only to factories and enterprises, but also to products intended for individual use.