Basic introduction Chinese name: greenhouse gas mbth: greenhouse gas; ; Greenhouse gases; GHG discipline: atmosphere, electricity, ocean, ecology, resources, main gases: water vapor, carbon dioxide, methane, freon, main hazards: international agreement on greenhouse effect: Kyoto Protocol, solution direction: types, functions, historical origins, main hazards, environmental hazards, climate impact, emission reduction measures, emission reduction policies, Europe, the United States, China and international agreements of main harmful gases. The six greenhouse gases specified in Kyoto Protocol are carbon dioxide (CO 2), methane (CH 4), nitrous oxide (N 2 O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF 6). Important greenhouse gases in the earth's atmosphere include carbon dioxide (CO 2), ozone (O 3), nitrous oxide (N 2 O), methane (CH 4), hydrofluorocarbons (CFCs, HFCs, HCFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF 6). Because the temporal and spatial distribution of water vapor and ozone changes greatly, these two gases are generally not considered when planning emission reduction measures. As for the Kyoto Protocol adopted by the Third Conference of the Parties to the United Nations Framework Convention on Climate Change held in Kyoto, Japan in 1997, it clearly stipulates the reduction of six greenhouse gases, including the above-mentioned: carbon dioxide (CO 2), methane (CH 4), nitrous oxide (N 2 O), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs). Among them, the latter three gases have the strongest ability to cause greenhouse effect, but in terms of the contribution percentage to global warming, the proportion of carbon dioxide is the largest, about 25%, which is because of its high content. Carbon dioxide (CO 2) in the atmosphere is the raw material for plant photosynthesis to synthesize carbohydrates. Its increase can increase photosynthetic products, which is undoubtedly beneficial to agricultural production. At the same time, it is a greenhouse gas, which has an important impact on the earth's thermal balance, so its increase affects agriculture by affecting climate change. In addition, there are trace gases with greenhouse effect in the atmosphere, such as methane, chlorofluorocarbons, carbon monoxide and ozone. Carbon dioxide accounts for about half of the total greenhouse effect, and the rest are the effects of the above trace gases. The concentration of carbon dioxide tends to increase year by year. In 1950s, its annual average mass fraction was about 3 15× 10(-6), but it increased to 325× 10(-6) in the early 1970s, exceeding 345× 10(-6), with an average annual increase of 65,438. According to most measurement results, the mass fraction of carbon dioxide before the industrial revolution was 275× 10(-6). The main reason for the increase of carbon dioxide concentration in the atmosphere is the large-scale exploitation and use of fossil fuels after industrialization. Since 1860, the average annual growth rate of carbon dioxide emissions from burning fossil fuels has been 4.22%, and the total emissions of various fuels have reached about 5 billion tons every year in the past 30 years. Another main reason for the increase of carbon dioxide in the atmosphere is cutting down trees as fuel. Forests used to be a "reservoir" of atmospheric carbon cycle, and each square meter of forests can assimilate 1-2 kg of carbon dioxide. Deforestation has turned the original "reservoir" of carbon dioxide into another "source" of carbon dioxide discharged into the atmosphere. According to FAO (1982), about 2.4 billion cubic meters of wood were cut down every year in the late 1970s, and about half of them were burned as firewood, resulting in an annual increase of carbon dioxide content of about 0.4× 10(-6). According to the above comprehensive analysis, if the concentration of greenhouse gases such as carbon dioxide increases at present, by the 265438+1930s, the total effect of the increase of greenhouse gases such as carbon dioxide will be equivalent to the level of doubling the concentration of carbon dioxide before industrialization, which will lead to a global temperature increase of 1.5-4.5℃, exceeding the temperature increase that has occurred in human history. As the temperature rises, the polar ice sheet may shrink, and the melting snow water can raise the sea level by 20- 140cm, which will have a serious direct impact on coastal cities. Methane molecule is the main component of natural gas and a clean energy gas. At the same time, it is an important greenhouse gas in the atmosphere. Its ability to absorb infrared rays is about 26 times that of carbon dioxide, and its greenhouse effect is 22 times higher than that of carbon dioxide, accounting for 15% of the total contribution of greenhouse gases, of which the content in the air is about 2ppm. Methane is produced by methane-producing bacteria or organisms rotting in an anoxic environment. Every year, the swamp will produce 65438+350 TG (1t =10/2), the paddy field will produce 100Tg, and the digestive system of cattle and sheep will produce 100-6544 during fermentation. Its average life in the atmosphere is about 8 years, which can be realized by the following chemical reactions: CH4+OH→CH3+H2O nitrous oxide nitrous oxide exists in the atmosphere for about 150 years. Although it is chemically inert in the troposphere, 90% of it can be decomposed by photolysis of solar radiation in the stratosphere, and the remaining 10% can react with active atomic oxygen O. Even so, N2O in the atmosphere is still increasing at a rate of 0.5-3Tg per year. N2O+HV→ N2+O (1d) N2O+O (1d) → N2+O2 N2O+O (1d) → 2 CFC-free (CFC-1and CFC-/) The ability of greenhouse gas to absorb infrared rays is determined by its own molecular structure. There are nonpolar valence bonds and polar valence bonds in the molecule. Molecules are also divided into polar molecules and nonpolar molecules. The strength of molecular polarity can be expressed by dipole moment μ. Only the vibration of dipole moment can cause observable infrared absorption spectrum, so the molecules of dipole moment are infrared active. However, the molecular vibration of δ μ = 0 can not produce infrared vibration absorption, so it is non-infrared active. In other words, greenhouse gases are infrared active molecules with dipole moment, so they have the ability to absorb infrared rays and preserve infrared heat energy. The main greenhouse gas in the atmosphere is water vapor (H2O), accounting for about 60%-70% of the total greenhouse effect, followed by carbon dioxide (CO 2), accounting for about 26%, and others are ozone (O 3), methane (CH 4), nitrous oxide (N 2 O), perfluorocarbons (PFCs) and hydrofluorocarbons (HCFCs). Before the historical origin of 1820, no one asked how the earth got heat. It was in that year that Jean-Baptist Joseph Fourier (1768- 1830, French mathematician and Egyptian scientist) returned to France. He wears a coat all the year round and spends most of his time studying heat transfer. He concluded that although the earth does reflect a lot of heat back into space, the atmosphere blocks some heat and reflects it back to the earth's surface. He compared it to a huge bell-shaped container, the top of which is composed of clouds and gas, which can retain enough heat to make the existence of life possible. His paper "Overview of Space Temperature of the Earth and Its Surface" was published in 1824. At that time, this paper was not his best work, and was not remembered until the end of 19. In fact, it is only because the infrared rays of the earth are absorbed by some gases or compounds in the atmosphere around the earth that the global temperature generally rises. Therefore, these gases are similar to greenhouse glass, only allowing sunlight to enter and preventing its reflection, thus achieving the functions of heat preservation and temperature rise, so they are called greenhouse gases. Including various oxides of water vapor, carbon dioxide and nitrogen in the atmosphere, as well as hydrofluorocarbons (HFCs), hydrofluorides, perfluorocarbons (PFCs), sulfur fluoride (SF6) and chlorofluorocarbons (CFCs) emitted by human activities in recent decades. Different species have different heat absorption capacity. The heat absorption capacity of methane per molecule is 2 1 times that of carbon dioxide, and the nitrogen oxides are higher, which is 270 times that of carbon dioxide. However, compared with some man-made greenhouse gases, hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) have the strongest heat absorption capacity so far. Climate change, a major environmental disaster, and its impact are multi-scale, all-round and multi-level, with both positive and negative effects, but the negative effects are more concerned. Global warming has had an impact on natural ecosystems in many areas, such as abnormal climate, sea level rise, glacier retreat, frozen soil melting, late freezing and early melting of river (lake) ice, prolonged growth period in middle and high latitudes, expansion of animal and plant distribution to polar regions and high altitudes, reduction of some animals and plants, early flowering of some plants and so on. Water vapor is the largest greenhouse gas, which is nearly two orders of magnitude higher than carbon dioxide, but it is greatly influenced by altitude and latitude, as well as by water climate and monsoon. Relatively speaking, the marine climate with high absolute humidity is not obviously affected by artificially discharged wet room gases, while areas with low absolute humidity such as high altitude, high latitude and arid areas are greatly affected by artificial greenhouse gases. For example, the Tianshan Mountains in China are located in inland high-altitude areas, and the snow line moves up obviously. In the United States, Europe and other regions, artificial greenhouse gases with high humidity accelerate water vapor convection, resulting in extremely low temperature and high temperature weather. Without the influence of water vapor, man-made greenhouse gases will generally cause the temperature to rise, but the existence of water vapor will increase atmospheric turbulence and make the climate extreme. The United States Environmental Protection Agency has determined that greenhouse gases such as carbon dioxide are air pollutants, "endangering public health and human well-being", and large-scale emission of greenhouse gases by human beings is enough to trigger climate changes such as global warming. The influence of climate on climate and ecosystem is a more complicated problem. Although the increase of carbon dioxide is beneficial to increase the photosynthetic products of green plants, the changes of temperature and precipitation caused by its increase will affect and change the climate production potential, thus changing the primary productivity of ecosystems and the land carrying capacity of agriculture. This indirect impact of climate change on ecosystems and agriculture may greatly exceed the direct impact of carbon dioxide itself on photosynthesis. According to the results of climate simulation test, doubling carbon dioxide may cause tropical expansion, subtropical zone, warm zone and cold zone to shrink, cold temperate zone to increase slightly, grassland and desert to increase, and forest to decrease. Carbon dioxide and climate change may affect a series of problems such as agricultural planting decision, variety layout and variety improvement, land use, agricultural input and technical improvement. Therefore, when formulating national development strategy and long-term agricultural planning, we should consider the climate and environmental changes that may be caused by the increase of carbon dioxide. This problem is particularly important and urgent for China, which is facing two major pressures: population expansion and poor per capita resources. Carbon dioxide emission reduction measures Fossil fuel combustion is the main source of man-made carbon dioxide emissions. When enterprises/industries respond, the directions to reduce carbon dioxide emissions include: CO2 gas energy substitution: replacing other fuels with natural gas. Adopt efficient or energy-saving equipment. Introduce renewable energy (wind power, solar energy, etc.). ). Evaluate and promote waste reuse. Recycling of resources. Save water, reduce waste water and reduce waste water treatment load. Reduce waste to reduce the load of waste incineration, burial or other physical and chemical treatment procedures. Saving electricity: lighting management, air conditioning management in summer and natural lighting and sun protection design of buildings. Develop and improve environmental protection signs or environmentally friendly products. Environmental greening. CH 4 emission reduction methane (CH 4) is mostly natural emission, and CH 4 emission has long been produced in nature due to biological anaerobic decomposition, such as lakes and wetlands with low water mobility. The factors causing CH 4 emission by human activities are the pollution of domestic sewage and industrial wastewater to natural water bodies, agricultural animal husbandry activities and industrial production processes. Methane structure agriculture/animal husbandry: organic compost management, proper odor treatment or energy recovery. Avoid burning agricultural wastes or burning large areas of agricultural land as a farming/development method. Industrial plan: reduce the leakage and escape of oil storage and transportation facilities. Properly manage and maintain the combustion system to reduce the frequency of accidents or tripping events. The oil storage tank is equipped with heat insulation device to reduce leakage. The coating is changed to a low-oil or non-oil coating. Biogas in landfills can ignite or recover energy. Biogas treatment or heat recovery for anaerobic treatment of wastewater field. The anthropogenic emission sources of N 2 O emission reduction are mostly related to agricultural/animal husbandry activities, and the emission of industrial projects is mainly related to chemical raw materials such as nitric acid and adipic acid (with nitric acid as one of the reaction raw materials). Agriculture/Animal Husbandry: Global Greenhouse Gas Emission Flowchart Organic Compost Management and Odor Treatment or Energy Recovery. Avoid burning agricultural wastes or burning large areas of agricultural land as a farming/development method. Industrial scheme: improve the yield of main products of related chemical reactions (scheme substitution or equipment improvement can be realized). NOx removal facilities are arranged at the back end of chemical reaction of related chemicals. Incinerators (especially biological sludge incinerators) are equipped with nitrogen oxides removal facilities. Properly treat domestic sewage. Other gases, such as hydrofluorocarbons (HFCs), sulfur hexafluoride (SF 6) and perfluorocarbons (PFCs), emit less hydrofluorocarbons (HFCs), sulfur hexafluoride (SF 6) and perfluorocarbons (PFCs), which are mostly used to replace ozone-depleting substances (ODS) in Montel Protocol tubes: CFCs. The related uses of hydrofluorocarbons and perfluorocarbons include refrigerants, fire extinguishing agents, gas gels, cleaning agents, foaming agents and so on. SF 6 is used for insulating gas, fire extinguishing agent, etc. These three controlled greenhouse gases may cause emissions during the manufacturing and use stages. When choosing CFC alternatives, alternatives with low global warming potential should be considered. Global warming potential values are shown in the table column. Air conditioning, fire extinguishing system related pipeline to avoid leakage. When it is used for cleaning solvent, it is improved with other cleaning procedures and cleaning facilities to improve cleaning efficiency and reduce the amount of cleaning solvent. The cleaning solvent recovery system was improved, which increased the recovery amount and reduced the solvent loss. The manufacturing procedure of foam products is to collect and treat waste gas. Emission reduction policies Developed countries in Europe mainly adopt comprehensive economic and financial policies to reduce greenhouse gas emissions, including: voluntary agreements, energy/carbon dioxide taxes, emissions trade, renewable energy or cogeneration production quotas, energy efficiency standards, direct financial incentives for renewable energy such as preferential tax rates, grants, tax exemption measures, and so on. However, these policies are constantly changing with different implementations. Take the energy/carbon dioxide tax as an example, from a simple tax to a "tax+subsidy". From the early 1990s, some developed countries began to implement carbon dioxide tax based on the carbon content of energy or fuel to increase fiscal revenue and/or reduce dependence on foreign oil supply. Because energy/carbon dioxide tax can reduce energy consumption and greenhouse gas emissions, many developed countries regard energy/carbon dioxide tax as an important measure to reduce greenhouse gas emissions. But later, in order to avoid the impact of energy/carbon dioxide tax on the competitiveness of domestic industries in the world market, some countries imposed low tax rates on high-energy-consuming sectors, Norway reduced the carbon dioxide tax rate of offshore oil and gas production, Sweden changed the carbon dioxide tax rate to 35% of the standard tax rate, and some energy-intensive industries also reduced the tax rate to near zero, while the tax rate of energy-intensive industries in Britain was only 20% of the standard tax rate. In order to stimulate the development of energy-saving technologies and avoid affecting the competitiveness of domestic industries in the international market, many countries have changed taxes into subsidies. Tax incentives or tax reductions have been implemented for energy-saving technologies such as renewable energy and cogeneration to encourage their supply and consumption. From the supply side, it mainly includes preferential treatment or reduction of various taxes related to renewable energy production or cogeneration, such as product tax, fixed assets tax, value-added tax, import tariff, etc. Britain has formulated preferential tax policies for the development of cogeneration. In 2002, the installed capacity of cogeneration in Britain was 4700MW. According to the goal of * * *, an efficient cogeneration of 10000MW will be built by 20 10. Therefore, the United Kingdom does not levy climate change tax on cogeneration, and provides investment subsidies to enterprises investing in cogeneration in the form of tax incentives. France reduces the corporate tax of cogeneration enterprises by 50%, and local governments can increase the reduction to 100% at most. Tax incentives have also been implemented for the use of renewable energy. Reduce the procurement cost of renewable energy equipment by tax incentives and reducing the value-added tax rate 15%. At the same time, enterprises investing in renewable energy can enjoy the policy of accelerating depreciation after one year. On February 7th, 2009, Lisa P. Jackson, Director of the Environmental Protection Agency (EPA), reiterated that greenhouse gases would pose a threat to public health and the natural environment, called for * * * to strengthen the implementation of the Clean Air Act, and said that EPA was considering making new regulations to further limit the exhaust emissions of power plants, oil refineries, chemical plants and cement plants. China and China attach great importance to and actively respond to climate change. In 2007, China * * * established the "National Leading Group on Climate Change" headed by Premier * * *. In the same year, China * * * issued the China National Program to Address Climate Change, which is the first national program to address climate change in China developing countries. According to the plan, by 20 10, the national energy consumption per unit of GDP will be reduced by about 20% compared with 2005. China * * * also proposed in the Medium-and Long-term Development Plan of Renewable Energy that by 2065,438+00, the consumption of renewable energy should reach 65,438+00% of the total energy consumption, and by 2020 it will reach about 65,438+05%. In order to ensure the realization of these goals, China has adopted a series of powerful policies and measures, and achieved remarkable results. In 20 13, China will comprehensively carry out the provincial climate change response plan to ensure the effective implementation of the national climate change response plan. In addition, China's economic plan has allocated 2 10 billion yuan for energy conservation, emission reduction and ecological engineering, and 370 billion yuan for structural adjustment and technological transformation. People's livelihood projects are 400 billion yuan, mainly used for the construction of affordable housing, and energy-saving and environmental protection materials will be actively adopted; There are 370 billion livelihood projects in rural areas, with the goal of improving rural living standards in a sustainable and environmentally friendly way. While trying to cope with climate change, it should be emphasized that China is a low-income developing country with a per capita GDP of only $3,000. According to the poverty standard of the United Nations, there are still 65.438+0.5 billion poor people in China. China has no choice but to face the multiple pressures of developing economy, eliminating poverty and slowing down greenhouse gas emissions. In this process, the international community believes that China will actively take measures to deal with climate change within its capacity. The international community hopes that the Copenhagen conference will achieve positive results. We believe that the key to the success of the Copenhagen conference lies in whether the requirements of the Agreement and the Kyoto Protocol can be implemented. As a whole, developed countries should reduce emissions by at least 25%-40% at the level of 1990 by 2020. Non-developed country Parties to the Protocol should undertake to comply with comparable quantitative emission reduction targets. Developed countries should fulfill their stipulated obligations, transfer technology and provide financial support to developing countries, so that developing countries can effectively cope with climate change. In addition, appropriate mechanisms and institutional guarantees should be established for compliance, financial support and technology transfer. With the support of "measurable, reportable and verifiable" funds, technology and capacity building in developed countries, developing countries will take appropriate mitigation actions according to their national conditions under the framework of sustainable development. At present, the intensification of the global financial crisis has brought severe challenges to countries' efforts to deal with climate change. However, as climate change is a more long-term and severe challenge, the international community's determination to deal with climate change cannot be shaken, its actions cannot be relaxed, and its efforts cannot be weakened. In fact, if the international financial crisis is handled properly, it can also turn challenges into opportunities and achieve a win-win situation for climate protection and development. China will take active measures to deal with climate change and make new contributions to the protection of the global climate system with a highly responsible attitude towards the interests of its own people and all mankind. (The writer is deputy director of the National Development and Reform Commission of China and special representative of China on climate change. Copyright: Project Consortium, 2009. ) international agreement1997 65438+February1kloc-0/,the third conference of the parties to the United Nations Framework Convention on Climate Change was held in Kyoto, Japan, which gave birth to the Kyoto Protocol, the first additional agreement to the Convention. On February 16, 2005, the Kyoto Protocol came into effect, which was the first time in human history to limit greenhouse gas emissions in the form of laws and regulations. The Kyoto Protocol aims to reduce the emissions of six greenhouse gases, such as carbon dioxide, in major industrialized countries by an average of 5.2% from 2008 to 20 12 on the basis of 1990. Greenhouse gases for emission reduction include carbon dioxide (CO 2), methane (CH 4), nitrous oxide (N 2 O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF 6). Among them, the European Union cut 8%, the United States cut 7%, Japan cut 6%, Canada cut 6%, and Eastern European countries cut 5% to 8%. New Zealand, Russia and Ukraine can stabilize their emissions at the level of 1990. The Protocol also allows Ireland, Australia and Norway to increase their emissions by 65,438+00%, 8% and 65,438+0% respectively compared with 65,438+090. However, the Protocol does not stipulate the specific emission reduction obligations of developing countries including China. Cooperation Mechanism of Kyoto Protocol The Kyoto Protocol has established three new flexible cooperation mechanisms aimed at reducing greenhouse gases-International Emissions Trading Mechanism (et), Joint Implementation Mechanism (ji) and Clean Development Mechanism (cdm). Emissions trading and joint implementation mainly involve cooperation among Parties included in Annex I; The clean development mechanism involves the cooperative relationship between Annex I Parties and developing country Parties in carbon dioxide emission reduction trading. In order to promote countries to achieve greenhouse gas emission reduction targets, the protocol allows the following four ways to reduce emissions: 1. The "emission trading" between two developed countries can buy and sell emission quotas, that is, countries that are difficult to complete emission reduction tasks can spend money to buy excess quotas from countries that have exceeded their tasks. 2. Use "net emissions" to calculate greenhouse gas emissions, that is, deduct the amount of carbon dioxide absorbed by forests from the actual national emissions. 3. Developed and developing countries can be urged to reduce greenhouse gas emissions through the green development mechanism. 4. The "group model" can be adopted, that is, many countries in the EU can be regarded as a whole, some countries cut back, some countries increase, and the emission reduction task can be completed as a whole. Important event In June 2009, 165438+ 10, the emails and documents of many top climatologists in the world were made public by hackers. E-mails and archives show that some scientists are manipulating data and falsifying scientific processes to support their claims about climate change. People's attention began to turn to the credibility of global warming. The list of scientists was not released at the same time, and some analysts pointed out that this incident may have a certain impact on the Copenhagen Climate Conference. 2012 1 65438+1October 2 1 day, the world meteorological organization released its annual greenhouse gas bulletin in Geneva on February 21day, saying that in 20 10, the greenhouse gas content in the earth's atmosphere reached a new high since the industrial age. Among them, the concentration of carbon dioxide in the atmosphere increased by 2.3 ppm( 1 ppm is one in a million) compared with 2009, reaching 389PPM, which is higher than the average annual growth level of 2.0PPM in recent 10 years and the average annual growth level of 1.5 ppm in the 1990s. Due to the extensive use of fossil fuels, deforestation and the change of land use, the concentration of carbon dioxide in the atmosphere has increased by 39% since the industrialization of 1750. In addition, in 20 10, the methane concentration in the atmosphere increased by 5 ppb( 1 ppb was one billion) compared with the previous year, reaching 1808PPB, which was 158% higher than the level of 1750. At the same time, the concentration of nitrous oxide, another greenhouse gas, has also increased to a certain extent, reaching 323.2PPB, which is 20% higher than the level of 1750.