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Greenhouse gases



The main greenhouse gas is water vapor (H 2 O), which is responsible for approximately two-thirds of natural greenhouse effect. Other major greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and fluorinated greenhouse gases. These gases are regulated by the Kyoto Protocol.

CFCs and HCFCs are also greenhouse gases, but are regulated by the Montreal rather than the Kyoto Protocol.

Stratospheric ozone is itself a greenhouse gas. Thus, ozone depletion served to mitigate some aspects of climate change, while restoration of the ozone layer would add to climate change.

Carbon dioxide

The main participant in the enhancement of the (artificial) greenhouse effect is carbon dioxide (CO 2). In industrialized countries, CO 2 represents more than 80% of emissions greenhouse gases.

Currently, more than 25 billion tons are released in the world carbon dioxide every year. CO 2/sub> can remain in the atmosphere for 50 to 200 years, depending on how it is returned to the earth and oceans.

Methane

The second most important greenhouse gas for enhancing the greenhouse effect is methane CH4. Since the beginning of the Industrial Revolution, atmospheric methane concentrations have doubled and contribute 20% of the contribution to the greenhouse gas effect. In industrialized countries, methane typically accounts for 15% of greenhouse gas emissions.

Anthropogenic methane emissions are associated with mining, combustion organic fuel, cattle ranching, rice farming and landfills.
The GWP of methane is 23 times greater than that of CO 2 .

Nitrous oxide

Nitrous oxide (N2O) is naturally released from the oceans and tropical forests and bacteria in soils. Sources of human influence include nitrogenous fertilizers, combustion of fossil fuels and industrial production chemicals that use nitrogen, such as wastewater treatment.

In industrialized countries, N2O is responsible for approximately 6% of greenhouse gas emissions. Like CO 2 and methane, nitrous oxide is a greenhouse gas whose molecules absorb heat that tries to evaporate into space. N 2 O has 310 times greater potential than CO 2 .

Since the beginning of the Industrial Revolution, atmospheric concentrations of nitrous oxide have increased by 16% and contribute 4 to 6% to the greenhouse effect.

Fluorinated greenhouse gases

The final group of greenhouse gases includes fluorinated constituents such as hydrofluorocarbons (HFCs), which are used as refrigerants and blowing agents; perfluorinated carbons (PFCs), which are released during aluminum production; and sulfur hexafluorides (SGF-SF 6), which are used in the electronics industry.

These are the only greenhouse gases that are not produced in nature.

Atmospheric concentrations are small, accounting for about 1.5% of the total greenhouse gas emissions of industrialized countries. However, they are extremely powerful; they have 1000-4000 times more potential than CO 2, and some have more than 22,000 times more potential.

HFCs are one of the alternatives to HCFCs in refrigeration, air conditioning and foaming. The consequences of these powerful greenhouse capabilities are therefore one factor that must be taken into account when selecting alternatives and developing elimination strategies.

One of the main greenhouse gases is carbon dioxide - carbon dioxide (CO2). Until recently, its role was overemphasized; up to half of the total contribution to the greenhouse effect was attributed to it. However, we have now come to the conclusion that this estimate was overestimated.

It has been instrumentally proven that in recent decades the annual accumulation of CO 2 in the atmosphere is 0.4%. Since the beginning of the 20th century. the level of CO 2 in the atmosphere increased by 31%. This value is essential to increase the temperature. According to the most optimistic scenario, the temperature will increase in the next century by 1.5-2°C, and the most pessimistic scenario - 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 in the processes of photosynthesis, and the remaining 3 billion tons are accumulated. The total amount of accumulation due to human fault over the past 100 years has amounted to about 170 billion tons. The given data should be considered in comparison with the 190 billion tons of carbon dioxide that enter the atmosphere annually as a result of natural processes. According to estimates by a number of Russian scientists, the contribution of anthropogenic activities to global warming is only 10-15%, and the rest is due to global natural cycles. Therefore, human efforts to reduce greenhouse gas emissions are unlikely to significantly slow down the coming warming.

An increase in CO 2 concentration does not mean death for the biosphere. Millions of years ago, in Carboniferous period, the concentration of CO 2 was 10 times higher than now. At that time, vegetation developed wildly, trees reached large sizes. But conditions were unfavorable for the human population. The maximum upper level of CO2 content 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 the combustion of organic fuel. The second hypothesis considers the main reason for the increase in CO 2 content to be the dysfunction of microbial communities in the soils of Siberia and parts of North America. Regardless of the choice of hypothesis, carbon dioxide accumulation occurs on an ever-increasing scale.

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

Underestimated until recently role of methane(SN 4). It is actively involved in the greenhouse effect. In addition, rising to a height of 15-20 km, methane under the influence sun rays decomposes into hydrogen and carbon, which, when combined with oxygen, forms 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. An 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 on the ocean floor.

Anthropogenic methane emissions are associated with exploration and extraction of mineral resources, with the combustion of mineral fuels in thermal power plants and fossil fuels in engines internal combustion vehicles, its allocation to livestock farms. Nitrogen fertilizer use, rice cultivation, landfills household waste, leaks and incomplete combustion 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 the growth has been 145%.

Nitrogen oxides accumulate in the atmosphere per year within 0.2%, and general accumulation during the period of intensive industrial development amounted to about 15%. The increase in the content of nitrogen oxides is caused by agricultural activities and massive destruction of forests.

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 intensifying the greenhouse effect. According to some scientists, about 60% of the greenhouse effect is caused by water vapor. The more of them there are in the troposphere, the stronger the greenhouse effect, and their concentration, in turn, depends on surface temperatures and the area of ​​the water surface.

Human production activities entail harmful effects on the atmosphere. This factor has already become a banality and only specialists in the environmental field pay attention to it. Meanwhile, harmful emissions pose increasingly pressing issues for organizations involved in global changes climate. The list of the most pressing problems at conferences dedicated to ecology regularly includes greenhouse gases 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 heating of the atmosphere. There are several sources of formation of such gases, including biological phenomena. Now it’s worth taking a closer look at the composition of greenhouse mixtures.

Water vapor as the main greenhouse gas

Gases of this type form about 60% of the total volume of substances that create As the Earth's temperature increases, evaporation and total concentration in the atmosphere also increase. At the same time, the same level of humidity is maintained, which contributes to the greenhouse effect. The natural essence that greenhouse gas possesses in the form of vapor undoubtedly has positive aspects in the matter of natural regulation atmospheric composition. But there is also negative consequences this process. The fact is that against the backdrop of rising humidity, there is also an increase in cloud mass, which reflects the direct rays of the sun. As a result, an anti-greenhouse effect occurs, in which the intensity of thermal radiation and, accordingly, heating of the atmosphere decreases.

Carbon dioxide

Among the main sources of this type of emissions are volcanic eruptions, human activity 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 actively participates in the processes of biocenosis. It is also the most durable in terms of staying in the atmosphere. According to some information, 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 precisely such ideas that are the main motivation for developing measures to counteract the greenhouse effect.

Methane

It persists in the atmosphere for about 10 years. Previously, it was believed that the effect of methane on stimulating the greenhouse effect is 25 times greater than carbon dioxide. But the last ones scientific research gave even more pessimistic results - it turned out that the potential impact of this gas was underestimated. However, the situation is mitigated by a short period during which the atmosphere retains methane. This type of greenhouse gas occurs as a result of anthropogenic activities. This could be rice growing, digestive fermentation, deforestation, etc. According to some studies, an intensive increase in methane concentration took place in the first millennium AD. Such phenomena were associated precisely with the expansion of cattle breeding and agricultural production, as well as with the burning of forests. Methane concentrations declined over subsequent centuries, although the trend is reversed today.

Ozone

Greenhouse gas mixtures contain not only dangerous components, but also beneficial parts. These include ozone, which protects the Earth from ultraviolet light. However, not everything is clear here either. Scientists divide this gas into two categories - tropospheric and stratospheric. As for the first, 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. In this case, the stratosphere layer acts as the main protection against the effects of harmful radiation. In regions where this type of greenhouse gas has an increased concentration, strong impacts on vegetation, which manifest themselves in inhibition of photosynthetic potential.

Counteracting the greenhouse effect

There are several directions in which work is being done on methods to curb this process. Among the main measures, the use of tools for regulating the interaction of greenhouse gas accumulators and sinks stands out. In particular, environmental agreements at the local level contribute to active development forestry. It is also worth noting the reforestation measures, which in the future will help minimize the greenhouse effect. Gas released into the atmosphere from manufacturing can also be reduced in many industries. To achieve this, measures are being introduced to limit emissions in transport, including production areas, at power plants, etc. For this purpose, alternative methods of fuel processing and gas removal systems are being developed. For example, in lately A recovery system is being actively implemented, thanks to which enterprises optimize their waste disposal processes.

Conclusion

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

In connection with the release of some resolutions, letters and methodological instructions Natural resource users are asking questions regarding the calculation of greenhouse gas emissions, but regulatory authorities do not yet have clear answers. Nevertheless, the issue is being actively discussed. Starting with basic knowledge And historical information about greenhouse gases, we will try to cover this topic for all interested parties, even those far from ecology.

What are greenhouse gas emissions and why are they dangerous: history of the issue

DICTIONARY

Greenhouse gases are gases with high transparency in the visible range and high absorption in the far infrared range. The presence of such gases causes the greenhouse effect - an increase in the temperature of the lower layers of the planet's atmosphere.

For the Earth, water vapor and carbon dioxide are of primary importance. An increase in the amount of carbon dioxide due to industrial emissions into the atmosphere leads to an increase in surface temperatures, which, according to the theory of global warming, leads to disruption of natural climatic processes.

Due to this danger, it is necessary to reduce GHG emissions, and therefore, in 1997, an agreement was concluded in Kyoto - the Kyoto Protocol, created as additional document to the 1992 UN Framework Convention on Climate Change.

In 2015, a new agreement was signed in Paris regulating measures to reduce carbon dioxide in the atmosphere from 2020.

The new agreement was signed by Russia, but not ratified: in the summer of 2016, the business community asked the president not to approve this document, because this will be bad for the economy. In addition, S. Lavrov, in his speech at the summit global development at the UN General Assembly stated that Russia has exceeded its commitments to achieve GHG emissions below 1990 levels.

Reducing greenhouse gas emissions in Russia: work plan

However, we did not stop there. Our country has taken a number of steps to reduce GHG emissions and reduce the danger of global warming in the world. Primarily developed legislative framework on this issue.

Greenhouse gases

Greenhouse gases- gases with high transparency in the visible range and high absorption in the far infrared range. The presence of such gases in the atmospheres of planets leads to the greenhouse effect.

The main greenhouse gas in the atmospheres of Venus and Mars is carbon dioxide, and in the Earth's atmosphere it is water vapor.

The main greenhouse gases, in order of their estimated impact on the Earth's heat balance, are water vapor, carbon dioxide, methane and ozone

Potentially, anthropogenic halogenated hydrocarbons and nitrogen oxides may also contribute to the greenhouse effect, but due to low concentrations in the atmosphere, assessing their contribution is problematic.

water vapor

Analysis of air bubbles in ice suggests there is more methane in the Earth's atmosphere now than at any time in the last 400,000 years. Since 1750, average global atmospheric methane concentrations have increased 150 percent, from approximately 700 to 1,745 parts per billion volume (ppbv) in 1998. Over the past decade, although methane concentrations have continued to rise, the rate of increase has slowed. In the late 1970s, the growth rate was about 20 ppbv per year. In the 1980s, growth slowed to 9-13 ppbv per year. Between 1990 and 1998 there was an increase of between 0 and 13 ppbv per year. Recent studies (Dlugokencky et al.) show a steady-state concentration of 1751 ppbv between 1999 and 2002.

Methane is removed from the atmosphere through several processes. The balance between methane emissions and removal processes ultimately determines atmospheric concentrations and the residence time of methane in the atmosphere. The dominant one is oxidation through a chemical reaction with hydroxyl radicals (OH). Methane reacts with OH in the troposphere to produce CH 3 and water. Stratospheric oxidation also plays some (minor) role in removing methane from the atmosphere. These two reactions with OH account for about 90% of methane removal from the atmosphere. In addition to the reaction with OH, two more processes are known: microbiological absorption of methane in soils and the reaction of methane with chlorine (Cl) atoms on the sea surface. The contribution of these processes is 7% and less than 2%, respectively.

Ozone

Ozone is a greenhouse gas. At the same time, ozone is essential for life because it protects the Earth from harsh ultraviolet radiation Sun.

However, scientists distinguish between stratospheric and tropospheric ozone. The first (so-called ozone layer) is a permanent and basic protection against harmful radiation. The second is considered harmful, since it can be transferred to the surface of the Earth, where it harms living beings, and, moreover, is unstable and cannot be a reliable protection. In addition, the increase in the content of tropospheric ozone contributed to the increase in the greenhouse effect of the atmosphere, which (according to the most widely accepted scientific estimates) is about 25% of the contribution of CO 2

Most tropospheric ozone is formed when nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds enter into chemical reactions in the presence of sunlight. Transport, industrial emissions, and some chemical solvents are the main sources of these substances in the atmosphere. Methane, whose atmospheric concentrations have increased significantly over the last century, also contributes to the formation of ozone. The lifetime of tropospheric ozone is approximately 22 days; the main mechanisms for its removal are binding in the soil, decomposition under the influence of ultraviolet rays and reactions with OH and HO 2 radicals.

Tropospheric ozone concentrations are highly variable and uneven in geographic distribution. There is a system for monitoring tropospheric ozone levels in the United States and Europe, based on satellites and ground-based observations. Since the formation of ozone requires sunlight, high levels ozone levels are usually observed during periods of hot and sunny weather. The current average concentration of tropospheric ozone in Europe is three times higher than in the pre-industrial era.

The increase in ozone concentration near the surface has a strong negative impact on vegetation, damaging leaves and inhibiting their photosynthetic potential. The historical process of increasing ground-level ozone concentrations likely suppressed the ability of land surfaces to absorb CO 2 and therefore increased the rate of CO 2 growth in the 20th century. Scientists (Sitch et al. 2007) believe that this indirect impact climate change nearly doubled the contribution that ground-level ozone concentrations made to climate change. Reducing lower tropospheric ozone pollution could offset 1–2 decades of CO 2 emissions at relatively low economic costs (Wallack and Ramanathan, 2009).

Nitric oxide

The greenhouse activity of nitrous oxide is 298 times higher than that of carbon dioxide.

Freons

The greenhouse activity of freons is 1300-8500 times higher than that of carbon dioxide. The main sources of freon are refrigeration units and aerosols.

See also

• Kyoto Protocol (CO 2 , CH 4 , HFCs, PFCs, N 2 O, SF 6)

Notes

Links

• Point Carbon is an analytics company specializing in providing independent estimates, forecasts, and information on greenhouse gas emissions trading.
• “GIS – atmosphere” automatic system for monitoring atmospheric air quality