Greenhouse gas

from Wikipedia, the free encyclopedia
Development of the proportion of greenhouse gases in the earth's atmosphere since 1978 and 1979
Distribution of water vapor in the earth's atmosphere on a given day. The amount of water vapor in the entire column of air above the surface of the earth is given as the thickness of a water layer condensable therefrom in cm.
Proportion of various greenhouse gas emissions by human polluter in 2000. Large graphic: all greenhouse gases

Greenhouse gases ( GHG ) are (trace) gases that contribute to the greenhouse effect (on earth or other planets) and can be of both natural and anthropogenic origin. They absorb part of the long-wave ( infrared ) heat radiation (thermal radiation) given off by the ground , which would otherwise escape into space . Depending on their local temperature, they emit the energy absorbed mainly as thermal radiation, the proportion of which is directed towards the earth is called atmospheric counter-radiation . This heats the earth's surface in addition to the short to long-wave direct sunlight . The natural greenhouse gases, especially water vapor , raise the average temperature on the earth's surface by around 33 K to +15 ° C. Without this natural greenhouse effect, the earth's surface would only have a global mean temperature of −18 ° C, which would hardly make more highly organized life on earth possible.

The current increase in the concentration of various greenhouse gases, especially carbon dioxide (CO 2 ), caused by human activities , intensifies the natural greenhouse effect and leads to global warming , which in turn is associated with numerous consequences . This additional, human-made part of the greenhouse effect is called the anthropogenic greenhouse effect.

In the Framework Convention on Climate Change in 1992, the international community declared that it wanted to stabilize greenhouse gas concentrations at a level that would prevent dangerous disruption of the climate system . It agreed in the Kyoto Protocol (1997) and the Paris Agreement (2015) to limit and reduce its greenhouse gas emissions. Meanwhile, the concentrations of the most important long-lived greenhouse gases carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) are increasing. The concentration of CO 2 has increased by 44% since the beginning of industrialization to around 410 ppm (as of 2019), the highest value for at least 800,000 years. The main cause is the use of fossil fuels . Energy -related CO 2 emissions grew at a record rate of 1.7% in 2018. The atmospheric concentration of methane rose to over 1850 ppb in 2017, that of nitrous oxide to around 330 ppb.

Greenhouse gases from the Kyoto Protocol

Anthropogenic greenhouse gas emissions of the world's 20 largest emitters (2014)
Country total (million t CO 2 -eq ) Share of global emissions per person (t)
China 11912 26.0% 08.7
United States 06371 13.9% 20.0
EU 04054 08.9% 08.0
India 03080 06.7% 02.4
Russia 02137 04.7% 14.8
Japan 01315 02.9% 10.3
Brazil 01051 02.3% 05.1
Germany 00854 01.9% 10.5
Indonesia 00789 01.7% 03.1
Canada 00745 01.6% 21.0
Iran 00734 01.6% 09.4
Mexico 00722 01.6% 05.8
South Korea 00671 01.5% 13.2
Australia 00589 01.3% 25.1
Saudi Arabia 00583 01.3% 19.0
South Africa 00525 01.1% 09.7
00506 01.1% 07.8
Turkey 00431 00.9% 05.6
France 00413 00.9% 06.2
Italy 00403 00.9% 06.6
Total 33832 74.0% -
The 20 largest emitters, based on emissions per inhabitant
Status: 2014; Source: WRI , CAIT Climate Data Explorer

All information without changes in land use.
For a complete listing, see the list of countries by greenhouse gas emissions .

In the Kyoto Protocol , a binding international agreement to reduce anthropogenic emissions of important greenhouse gases ( direct greenhouse gases ) was agreed. The gases regulated in the Kyoto Protocol are: carbon dioxide (CO 2 , serves as a reference value), methane (CH 4 ), nitrous oxide (laughing gas, N 2 O), partially halogenated fluorocarbons (HFCs / HFCs), perfluorinated hydrocarbons (HFCs / PFCs ), Sulfur hexafluoride (SF 6 ). Since 2012, nitrogen trifluoride (NF 3 ) has also been regulated as an additional greenhouse gas. There are also fluorinated greenhouse gases (F-gases), as this in the atmosphere high because of its high retention global warming potential exhibit. Other greenhouse gases, the indirect greenhouse gases , such as B. carbon monoxide (CO), nitrogen oxides (NO x ) or volatile hydrocarbons without methane (so-called NMVOC ) are regulated in the Montreal Protocol because they contribute to the destruction of the ozone layer.

The goal of reducing the emissions of the industrialized countries participating in Phase I of the Kyoto Protocol by 5.2% compared to 1990 was achieved. However, these emission reductions are by no means sufficient to limit the temperature rise to 2 ° C. The US refused to sign the Kyoto Protocol - but there are efforts being made at the local and state levels. In 2013, California was on the way to achieving its self-imposed reduction target of not emitting more greenhouse gases in 2020 than in 1990. China and India were not subject to any reduction commitments. Other countries, such as Japan, did not achieve their reduction targets. Canada withdrew from the protocol, avoiding fines for failing to meet its mitigation targets.

carbon dioxide

Carbon dioxide (CO 2 ) is present in the atmosphere with a share of around 0.04% (approx. 410 ppm, as of 2019) and has a share of 9 to 26% in the natural greenhouse effect.

The geogenic and biogenic , i.e. natural, CO 2 production is approx. 550 Gt per year. In the carbon cycle , this is offset by an almost equally high natural consumption, particularly through photosynthesis , but also through binding in calcifying organisms.

Carbon dioxide is formed u. a. in the combustion of fossil fuels (through traffic, heating, electricity generation, industry). Its mean atmospheric residence time is approx. 120 years. Global anthropogenic CO 2 emissions were around 32 gigatons (Gt) in 2006 and account  for around 60% of the additional man-made greenhouse effect.

Emissions from human activity have increased the concentration of CO 2 in the earth's atmosphere from 280 ppm by over 40% to well over 400 ppm (2019) since the beginning of industrialization. The current concentration is thus higher than in the last 800,000 years. Probably during the last 14 million years (since the climatic optimum of the Middle Miocene ) no significantly higher CO 2 values ​​than in the previous 21st century occurred.

A number of naturally occurring processes act as sinks for atmospheric carbon dioxide (i.e., they remove CO 2 from the atmosphere); however, the anthropogenic increase in concentration can only be compensated for over periods of centuries and decades. These processes can currently only dampen the increase in CO 2 concentration that has been ongoing since the middle of the 19th century , but cannot compensate for it. The degree of binding of additional carbon dioxide is an uncertainty factor when parameterizing climate models.

The increased uptake by land and marine plants as part of their photosynthetic capacity is the fastest acting mechanism that dampens the rise in atmospheric gas concentration and acts immediately. In 2010, twice as much additional carbon dioxide released by humans was absorbed by the biosphere as in 1960, while the rate of emissions quadrupled.

The second fastest mechanism is the dissolution of the gas in seawater, a process that works over a period of centuries, as the oceans take a long time to mix. The dissolution of part of the additional carbon dioxide in the sea dampens the greenhouse effect, but leads to lower pH values ​​of the water through the formation of carbonic acid ( acidification of the oceans ). This is followed by the reaction of the acidic sea water with the lime of the ocean sediments. This removes carbon dioxide from the cycle over a period of millennia.

The slowest-acting response is rock weathering, a process that spans centuries. Climate simulations indicate that due to the long time constant of the last-mentioned processes, the earth heated by the increased carbon dioxide concentration will only cool down by around 1 K per 12,000 years.


Anthropogenic methane emissions worldwide:
5.9 billion t CO 2 equivalents
Spread of methane emissions in the earth's atmosphere

Methane (CH 4 ) also only occurs in traces in the earth's atmosphere (<2 ppm). Approximately half of anthropogenic methane is produced in global agriculture and forestry and other uses of land and biomaterial, in animal production (especially in ruminants such as cattle , sheep and goats ), in sewage treatment plants and landfills . The other half is released in the industrial sector through leaks during extraction, transport and processing, especially of natural gas and, through incomplete combustion during flaring, of technically unusable gases. In addition, methane is also released from many non-flowing bodies of water (e.g. rice fields ), here organic material is decomposed by microorganisms (e.g. archaea ) anaerobically into digester gases (mainly methane).

Around 20% of all methane emissions come from inland waters , where the tufted mosquitoes also cause some of the emissions. They use the gases from the sediments as a means of buoyancy when they go to the surface of the water to eat.

An indirect effect is the release when the permafrost soil thaws . Another such source is methane hydrate stored in large quantities on and in the continental margins , a solid that breaks down into methane and water when heated.

Due to its high effectiveness (25 times more effective than CO 2 ), methane contributes around 20% to the anthropogenic greenhouse effect. The dwell time in the atmosphere is 9 to 15 years, which is significantly shorter than with CO 2 . Up to 37% of the anthropogenic methane emitted worldwide (around 5.9 Gt CO 2 equivalent) comes directly or indirectly from livestock farming. Most of this comes from fermentation processes in the stomach of ruminants . According to the Federal Environment Agency, around 54% of all methane emissions and over 77% of nitrous oxide emissions in Germany came from agriculture in 2013.

The global mean methane content of the earth's atmosphere has increased since pre-industrial times (1750) from around 700  ppb to 1,750 ppb in 1999. Between 1999 and 2006, the methane content in the atmosphere remained largely constant, but has since increased significantly to over 1800 ppb. There is thus far more methane in the atmosphere than there has ever been during the last 650,000 years - during this time the methane content fluctuated between 320 and 790 ppb, as was shown by examining ice cores .

The methane concentrations rose annually between 2000 and 2006 by about 0.5 particles per billion, after that at a rate more than ten times higher.

Climate change could increase greenhouse gas emissions from northern freshwater lakes by 1.5 to 2.7 times. This is because the vegetation cover in forests in the northern latitudes is increasing due to global warming and more organic molecules get into the waters, which are broken down by microbes in the lake sediments. During this degradation process, carbon dioxide and methane are released as by-products.

Numerous wells that were drilled for the purpose of fracking in the United States have been abandoned, and the wells often leak toxins and greenhouse gases, including methane in particular. According to the New York Times , the US government estimates the number of abandoned drilling sites at more than 3 million, and 2 million of them are not safely closed.

Nitrous oxide (laughing gas)

Anthropogenic nitrous oxide emissions worldwide in billion tonnes of CO 2 equivalent, total 3.4 billion tonnes, source

Laughing gas (N 2 O) is a greenhouse gas with a greenhouse effect 298 times that of CO 2 . According to the special report on climate change and land systems published in 2019, 82% of man-made nitrous oxide emissions are due to land use. Compared to conventional agriculture , organic farming produces around 40% less nitrous oxide per hectare.

Human-caused emissions come mainly from agriculture (livestock farming, fertilizers and the cultivation of legumes , biomass ), less from medical technology and from fossil fuel-operated power plants and transport. The most important source of N 2 O are microbial degradation processes of nitrogen compounds in the soil. These take place both under natural conditions and through nitrogen input from agriculture ( manure ), industry and traffic.
The formation of nitrous oxide has not yet been adequately researched. It is known, however, that a particularly large amount of N 2 O escapes into the air , especially in heavy, over-fertilized and moist soils . The precipitation of ammonium nitrogen from the air, which results from the evaporation of manure, can also contribute to the formation of laughing gas.

With a mean atmospheric dwell time of 114 years and a relatively high global warming potential, it is a climate-relevant gas. The breakdown of N 2 O takes place mainly through reaction with sunlight in the stratosphere. The volume share rose from pre-industrial 270 ppbV by around 20% to 322–323 ppbV (2010). Today's concentrations are higher than anything that has been detected in ice cores reaching back up to 800,000 years . The contribution of nitrous oxide to the anthropogenic greenhouse effect is currently estimated to be 6 to 9%.

N 2 O also plays a role in processes in the ozone layer , which in turn affect the greenhouse effect. B. Ozone splitting, catalyzed by halogen radicals, leads to a number of chemical processes in the lower stratosphere, in which methane, hydrogen and volatile organic substances are oxidized. Particularly in the cold and in the dark, N 2 O is able to form so-called reservoir species with the radicals, whereby the radicals are temporarily ineffective for ozone depletion (see ozone hole ) .

In December 2015, the Nitric Acid Climate Action Group was founded by the Federal Environment Ministry . This initiative aims to stop the emission of nitrous oxide in industry worldwide by 2020. In September 2016, the Association of the Chemical Industry (VCI) joined this initiative. In industry, nitrous oxide is produced B. in the production of the vitamin niacin . At the chemical company Lonza , nitrous oxide emissions amount to around 600,000 tonnes of CO 2 equivalents per year, which corresponds to around one percent of Switzerland's annual greenhouse gas emissions.


While the classic greenhouse gases usually arise as undesirable by-products, fluorocarbons and chlorofluorocarbons (CFCs) are mainly produced in a targeted manner and used as propellants , refrigerants or fire extinguishing agents. In order to reduce these substances, the development of substitute substances is required in addition to technical measures. They are used today in a similar way to the earlier use of the chlorofluorocarbons, which have only been used to a limited extent since 1995 and which are responsible for the destruction of the ozone layer and have a strong climate impact. The fluorinated hydrocarbons currently contribute around 10% to global warming. Some of these substances are up to 14,800 times more climate-effective than carbon dioxide. A further increase could give the greenhouse effect a massive boost.

When it comes to fluorocarbons, a distinction is made between partially halogenated fluorocarbons (HFCs) and fully halogenated fluorocarbons (HFCs). If PFCs are completely fluorinated (i.e. no longer contain hydrogen atoms), they are also called perfluorinated hydrocarbons (PFC).

Tetrafluoromethane (CF 4 ) in the atmosphere is partly of natural origin. Larger emissions come from primary aluminum production. Ethane and propane derivatives (C2, C3) of the fluorinated hydrocarbons are used as refrigerants. Some high molecular weight fluorinated hydrocarbons (C6 – C8) are used as cleaning agents. Furthermore, PFCs are used on a large scale in the plastics and polymer industry as starting materials for the production of fluorinated plastics, oils, fats, textiles and other chemicals (they are often produced using a CFC precursor), and are used in the electronics and screen industry as an etching gas and the like. v. a. m.

In the European F-Gas Regulation (published on June 14, 2006, amended on April 16, 2014) and its implementation in national law by the Chemicals Climate Protection Ordinance (ChemKlimaschutzV), measures have been taken to reduce emissions from refrigeration systems. In contrast to the CFC-Halon Prohibition Ordinance, this is not a ban on use, but rather the quantities released by leaks are to be reduced through higher requirements for the design and maintenance of refrigeration systems. In the period from 2008 to 2012 they are to be reduced by 8% compared to 1990 levels. In addition, the use of fluorinated greenhouse gases for certain activities is no longer permitted after certain reference dates (e.g. July 4, 2006, July 4, 2009, January 1, 2015 or January 1, 2020). In October 2016 in Kigali, the 197 states party to the Montreal Protocol agreed to reduce HFC emissions by 85% by 2047.

The content of fluorocarbons in the earth's atmosphere has been constant since 1999 or is even decreasing again in some cases.

Sulfur hexafluoride (SF 6 ) and nitrogen trifluoride (NF 3 )

According to studies by the Intergovernmental Panel on Climate Change (IPCC), sulfur hexafluoride is the most powerful known greenhouse gas. The mean residence time of SF 6 in the atmosphere is 3200 years. Its greenhouse effect is 22,800 times that of carbon dioxide (CO 2 ). Due to the very low concentration of SF 6 in the earth's atmosphere (approx. 0.005 ppb by volume, which corresponds to 0.12 ppmV CO 2 equivalent), its influence on global warming is small.

Sulfur hexafluoride, SF 6 , is used as an insulation gas or extinguishing gas in high-voltage switchgear and as an etching gas in the semiconductor industry. Until about the year 2000 it was also used as a filling gas for car tires and as a filling gas in soundproof insulating glass panes ; the use of sulfur hexafluoride as tire inflation gas has been banned since July 4th 2007. The gas is also important in the production of magnesium. It prevents the hot molten metal from coming into contact with the air. Due to the process, larger amounts escape into the atmosphere during this application, so alternative protective gases are being investigated.

There are also other highly effective greenhouse gases, such as B. nitrogen trifluoride , whose greenhouse effect is 17,200 times that of CO 2 . In 2008 the earth's atmosphere contained 5,400 tons of nitrogen trifluoride.

Other substances that contribute to the greenhouse effect


Water vapor is the most important greenhouse gas. Its contribution to the natural greenhouse effect is estimated at around 60% when the sky is clear. It comes mainly from the water cycle (ocean - evaporation - precipitation - storage in the ground) plus a small part from volcanism .

Humans indirectly increase the water vapor content in the atmosphere because global warming increases the air temperature and thus the rate of evaporation . This is the most important feedback factor that increases global warming .

In the stratosphere there are only traces of water vapor; he comes from Partly from air traffic and from the oxidation of methane to CO 2 and H 2 O and contributes to the greenhouse effect.

Ozone and its precursors

Ozone is also a climate-relevant gas, the concentrations of which are not influenced directly by humans, but only indirectly. Both stratospheric and tropospheric ozone concentrations influence the Earth's radiation budget. In contrast to CO 2 , for example, ozone is a gas that is not evenly distributed.

The ozone layer is located in the stratosphere above the tropopause , i.e. in a layer in which there is hardly any water. The stratosphere has an inverse temperature profile due to the ozone, which absorbs UV radiation from sunlight. H. the air warms up here with increasing altitude. That distinguishes them from the layers of air that surround them. The heating is strongest in the area of ​​the ozone layer, where the temperature rises from approx. −60 ° C to just under 0 ° C. If this ozone layer is damaged, more high-energy ultraviolet radiation reaches the earth's surface.

The highest density of ozone is at a height of 20 to 30 km, the highest volume fraction at about 40 km. All ozone that is in the atmosphere would result in a 3 mm high layer on the earth's surface at normal pressure. For comparison: the entire column of air would be 8 km high at normal pressure throughout. A thinning of the ozone layer, as it is caused by the emission of CFCs (→ ozone hole ), has a cooling effect on the troposphere.

In addition, there is ground-level ozone, which, with increasing concentration, leads to regional warming of ground-level air layers. In addition, higher concentrations of ozone close to the ground have a harmful effect on human health and plant physiology . Its atmospheric residence time is a few days to weeks.

Ground-level ozone is formed from various precursor substances ( nitrogen oxides , hydrocarbons such as methane , carbon monoxide ) when exposed to sunlight ( summer smog ). Human emissions of these precursor substances thus have an indirect effect on the climate. Carbon monoxide e.g. B. comes from microbial reactions in plants, soils and in the sea as well as from biomass combustion in furnaces (incomplete combustion) and from industry.


Strictly speaking, clouds , i.e. condensed water vapor, are not a greenhouse gas. But they also absorb infrared radiation and thereby increase the greenhouse effect. At the same time, clouds also reflect part of the incident solar energy and thus also have a cooling effect. Which effect prevails locally depends on factors such as altitude, time of day / height of the sun and the density of the clouds. Averaged globally, clouds have a cooling effect. Due to global warming, the cooling effect is likely to decrease, so the warming is intensified by this so-called cloud feedback.

Aerosols and soot particles

Aerosols are solid or liquid particles in the air and are also released into the atmosphere through human activity. These include particles from diesel soot and combustion of wood and coal. They are not counted among the greenhouse gases, but they also have an impact on global warming. Aerosols have a direct effect by absorbing and reflecting solar radiation and indirectly by contributing to cloud formation as condensation nuclei and changing cloud properties, which in turn influence the climate (see above). Overall, the human input of aerosols has had a cooling effect in recent years and thus dampened the global rise in temperature.

Depending on the type, aerosols have different effects. Sulphate aerosols have an overall cooling effect. Soot particles, on the other hand, absorb thermal radiation and lead to a lowering of the albedo on bright surfaces such as snow and thus to warming and accelerated melting of polar ice surfaces. Recent studies indicate that more soot is emitted and soot particles have a significantly greater warming effect than previously assumed. Reducing the amount of soot is an important and effective climate protection measure to delay global warming in the short term (atmospheric aerosol concentrations change comparatively quickly with changes in emissions, unlike changes in greenhouse gas concentrations, which persist long after emissions have been reduced).

The artificial introduction of aerosols into the stratosphere to reflect solar radiation and thus to cool the earth is occasionally put forward as a proposal to intervene in the climate within the framework of geoengineering and to counter global warming.

Effects of greenhouse gases

A large part of the solar radiation is absorbed on the earth's surface, converted into heat and given off again in the form of thermal radiation . Due to their chemical nature, greenhouse gases can absorb heat radiation to varying degrees and thus release the heat into the atmosphere. The global warming potential of a gas depends to a large extent on the extent to which its dipole moment can be changed by molecular vibrations . The diatomic gases oxygen and nitrogen do not change their dipole moment due to molecular vibrations, so they are transparent to infrared radiation. Large molecules such as CFCs, on the other hand, have very many levels of vibration and thus many times the global warming potential of, for example, CO 2 .

The greenhouse effect of a gas, i.e. how much the release of a gas can contribute to the greenhouse effect, essentially depends on three factors: the amount of gas released per unit of time (emission rate), the spectroscopic properties of the gas, i.e. H. how much it absorbs the thermal radiation in certain wavelength ranges and how long it remains in the atmosphere. The atmospheric residence time is the time that a substance remains in the atmosphere on average before it is removed from it again by chemical or other processes. The longer the residence time of a greenhouse gas, the higher the theoretical effect.

A measure of the greenhouse effect of a gas per kilogram of emissions is the global warming potential (GWP) in CO 2 equivalents, in which the absorption properties and the residence time are taken into account. The relative global warming potential is a value standardized for carbon dioxide with which the effect of a greenhouse gas is compared with the equivalent amount of carbon dioxide. For example, methane has a relative global warming potential of 25, i.e. H. 1 kg of methane has the same greenhouse effect as 25 kg of carbon dioxide.

The relative global warming potential is generally related to a time horizon of 100 years, i.e. the warming effect averaged over a period of 100 years after the emission is considered. If you relate it to a different time horizon, the relative global warming potential also changes according to the atmospheric length of stay. If a greenhouse gas contains one or more chlorine or fluorine atoms, its relative global warming potential increases significantly due to the high chemical stability compared to greenhouse gases without halogen atom (s).

Satellite-based measurements

Since January 2009, the concentration of the most important greenhouse gases has also been monitored from space. The Japanese satellite Ibuki (Eng. "Breath") provides current data on the distribution and concentration of carbon dioxide and methane around the globe. This gives climatology a better database for calculating global warming. Ibuki circles the earth at an altitude of 666 kilometers 14 times a day in 100 minutes each time and returns to the same places every three days. This enables the orbiter to measure gas concentrations at 56,000 points at an altitude of up to three kilometers above the earth's surface.

National greenhouse gas emissions and foreign trade

Imports and exports mean that the same products are not produced and consumed in one country. The emissions can be determined from two fundamentally different perspectives, depending on whether one wants to start from the total production or the total consumption of a country.

The differences can be considerable. In 2015, Switzerland reported consumption-related emissions that are around 2.5 times higher than production-related emissions.

Production-related emissions

Production-related emissions (including territorial emissions or domestic emissions) are all emissions that are released over the entire territory of a country. The country can directly influence these emissions through targeted political measures.

This methodology is used to create national greenhouse gas inventories in accordance with the requirements of the United Nations Framework Convention on Climate Change . The emissions can largely be calculated from the consumption of fossil fuels and by taking into account other activities in industry, agriculture and waste management.

The method is well established, but has been criticized because it cannot adequately take into account various aspects such as foreign trade, cross-border traffic and “carbon leakage” (a relocation of the emission-intensive industries abroad).

Consumption-related emissions

Consumption-related emissions refer to all emissions caused by a country's total consumption. They can arise in Germany as well as abroad. They take into account all emissions that are caused globally by imported products. In return, domestic emissions from the production of exported products are not taken into account.

The determination of the consumption-related emissions is - compared to the production-related - significantly more complex. A consideration of the individual traded products is not practicable. Instead, imported and exported emissions are approximately determined using the input-output analysis using national or international input-output tables .

The complexity of the calculation, the amount of data required and the dependence on foreign data lead to increased uncertainties in the results. Therefore, consumption-related emissions are currently not available for all countries and often only for individual years with sufficient quality.

For political decisions, the focus on consumption-related emissions can be seen as superior. In this way, “carbon leakage” can be better assessed globally, the reduction demands on developing countries can be appropriately assessed, comparative advantages in the environmental sector can be better emphasized and the spread of new technologies can be promoted.

CO 2 balances are normally based on consumption-related emissions.

Development of emissions


Development of greenhouse gas emissions in Germany (
- CO 2 , - CH 4 , NO 2 , F-gases , - targets )

With the Kyoto Protocol, Germany committed itself to reducing its greenhouse gas emissions on average between 2008 and 2012 by 21% below the 1990 level. This goal was achieved with a reduction of around 27% by 2011. For the period up to 2020, Germany has set itself the goal of reducing greenhouse gas emissions by 40% compared to 1990, by 55% by 2030, by 70% by 2040 and by 80 to 95% by 2050. In fact, emissions remained at an almost constant level in the years up to 2016. In view of the measures taken , the goal for 2020 is hardly achievable. In 2016, agriculture caused 65.2 million tonnes of CO 2 equivalent directly, primarily through animal husbandry and land use - 7.2% of total emissions. The federal government's national climate protection plan 2050 shows the necessary reduction steps in the various sectors with which the future targets are to be achieved.

  • Carbon dioxide : By 2016, emissions were 27.6% lower than in 1990. Important causes in the 1990s after German reunification were closures and modernizations in the new federal states. Since the 2000s, the switch to renewable energy sources has made a significant contribution to reducing emissions. The CO 2 emissions fluctuate with the heating demand triggered by weather conditions. Higher traffic volumes, increased exports of coal power and rising emissions from industry caused CO 2 emissions to rise again in 2014 and 2015 .
  • Methane : Emissions decreased by 53% between 1990 and 2014. The reasons given are the decline in waste landfilling (organic components are a main source of methane emissions), the decline in hard coal extraction and smaller animal populations. In 2015 the cattle and sheep herds rose again and with them methane emissions.
  • Nitrous oxide : emissions decreased by 40% between 1990 and 2014. Important sources of nitrous oxide emissions are agricultural soils, industrial processes and traffic. In 2015, nitrous oxide emissions from fertilization rose again.
  • " F-gases ": Here the emissions decreased by 14% compared to 1990. In the years before 2014, a slightly increasing trend was recorded because they were increasingly used as substitutes for the banned CFCs. Most recently, however, the one-off effect caused by the discontinuation of the production of R22 was offset by the increase in refrigerants and sulfur hexafluoride from installed products such as soundproof windows.


In Austria , greenhouse gas emissions increased from 2016 to 2017 to 82.3 million tons of CO 2 equivalent - an increase of 3.3%.

According to an estimate by the Federal Environment Agency on July 28, 2019, climate-damaging greenhouse gas emissions in Austria fell for the first time in three years in 2018, by 3.8% compared to 2017. However, emissions from traffic have increased. The reduction in emissions occurred despite economic growth of 2.7%. As of July 28, 2019, around 79.1 million tons of greenhouse gases were emitted in Austria in 2018. Compared to 2017, this means a decrease of 3.2 million tons. Chamber of Commerce President Mahrer speaks of a "trend reversal". From the perspective of WWF Austria, the greenhouse gas estimate for 2018 published on July 28, 2019 is absolutely no reason to cheer, but should be a wake-up call for measures that are long overdue. Because the decline "acclaimed" by the Ministry of the Environment is not due to structurally effective measures, but is primarily due to "the very mild weather with fewer heating days and special factors such as the maintenance of a VOESTALPINE blast furnace". In traffic, emissions have even risen from a high level. "Austria's climate policy is the world champion in glossing over modest progress," said a short teletext message on ORF2 on Sunday, July 28, 2019.

In the case of transport - the main source of CO 2 emissions - greenhouse gas emissions rose in 2018 as diesel and gasoline consumption increased by 0.8% and 0.2 million tons, respectively. According to the Federal Environment Agency in Austria, the overall decrease in 2018 is due to several individual factors: The consumption of heating oil and natural gas (minus 6.7%) fell more than the use of mineral fertilizers in agriculture (minus 1.9%) and the Number of cattle (minus 1.6%).


In Switzerland , traffic is the major contributor to greenhouse gas emissions. The greenhouse gases that Switzerland produces abroad are not counted towards the Swiss. If one were to add this, Switzerland's balance sheet would not look so good. Per person, Switzerland has behind Luxembourg and Belgium the largest CO 2 footprint in Europe. There are only 13 countries in the world that have an even higher CO 2 footprint per person than Switzerland. The Federal Council wants Switzerland to be climate-neutral by 2050 . With the Energy Strategy 2050 , u. a. Renewable energies are promoted.


CO 2 emissions: IPCC scenarios and actual (black line)

From a global perspective, greenhouse gas emissions rose at times more sharply than was estimated even in the worst-case scenarios of the IPCC assessment report published in 2007. Between 2009 and 2010 the increase in carbon emissions was 6%. This exceptionally high increase was mainly due to the 2009 economic crisis. In the years from 2014 to 2016, CO 2 emissions remained constant and was thus able to decouple from economic development for the first time. Preliminary estimates for 2017 assumed an increase in carbon dioxide emissions of around 1% compared to 2016.

In 2018, CO 2 emissions increased by 2% according to the BP Statistical Review of World Energy. More extreme weather conditions are cited as an explanation for this increase, which is the highest since 2011, with a higher number of unusually hot or unusually cold days. As a result, the increase in energy consumption was ultimately higher than the expansion of renewable energies that was driven forward during this period.

See also


  • P. Fabian: Carbon dioxide and other greenhouse gases: Air pollution and its impact on the climate. In: Practice of Science Chemistry. 45 (2), 1996, p. 2 ff. ISSN  0177-9516
  • Eike Roth: Global environmental problems - causes and possible solutions. Friedmann Verlag, Munich 2004, ISBN 3-933431-31-X .
  • M. Saunois, RB Jackson, P. Bousquet, B. Poulter, JG Canade: The growing role of methane in anthropogenic climate change. ("The growing role of methane in anthropogenic climate change"). In: Environmental Research Letters . Vol. 11, No. 12, December 12, 2016. doi: 10.1088 / 1748-9326 / 11/12/120207

Web links

Individual evidence

  1. Compared to a toy model , which is described under greenhouse effect # energy balance .
  2. ^ W. Roedel: Physics of our environment: The atmosphere. 2nd Edition. Springer, Berlin 1994, ISBN 3-540-57885-4 , p. 16.
  3. ^ IPCC, 2013: Summary for Policymakers. In: TF Stocker, D. Qin, G.-K. Plattner, M. Tignor, SK Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, PM Midgley (eds.): Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
  4. World Meteorological Organization : Greenhouse gas concentrations in atmosphere reach yet another high. November 25, 2019, accessed November 25, 2019 .
  5. a b Atmospheric greenhouse gas concentrations. Federal Environment Agency, June 3, 2020, accessed on June 24, 2020 .
  6. ^ J. Blunden, G. Hartfield, DS Arndt: State of the Climate in 2017 . Special Supplement to the Bulletin of the American Meteorological Society Vol. 99, No. 8, August 2018. August 2018, p. xvi ( [PDF; 18.7 MB ]).
  7. International Energy Agency (Ed.): Global Energy & CO 2 Status Report 2018 . March 2019.
  8. CAIT Climate Data Explorer. In: CAIT. World Resources Institute, accessed on February 29, 2020 (selected columns: country , Total GHG Emissions Excluding Land-Use Change and Forestry - 2014 , Total GHG Emissions Excluding Land-Use Change and Forestry Per Capita - 2014 , percentages as a proportion of the value world calculated in Total GHG Emissions Excluding Land-Use Change and Forestry - 2014 ).
  9. Appendix A of the Kyoto Protocol ( BGBl. 2015 II pp. 306, 317 ).
  10. Igor Shishlov, Romain Morel, Valentin Bell Assen: Compliance of the Parties to the Kyoto Protocol in the first commitment period . In: Climate Policy . tape 16 , no. October 6 , 2016, doi : 10.1080 / 14693062.2016.1164658 .
  11. Michael Grubb: Full legal compliance with the Kyoto Protocol's first commitment period - some lessons . In: Climate Policy . tape 16 , no. 6 , June 10, 2016, doi : 10.1080 / 14693062.2016.1194005 .
  12. Amanda M. Rosen: The Wrong Solution at the Right Time: The Failure of the Kyoto Protocol on Climate Change . In: Politics & Policy . February 15, 2015, doi : 10.1111 / polp.12105 .
  13. a b J. T. Kiehl, KE Trenberth: Earth's annual global mean energy budget. In: American Meteorological Society . Vol. 78, 1997, pp. 197–208 ( PDF , 221 kB)
  14. Frequently Asked Questions. Carbon Dioxide Information Analysis Center (CDIAC), accessed July 6, 2014 .
  15. ^ Yi Ge Zhang, Mark Pagani, Zhonghui Liu, Steven M. Bohaty, Robert DeConto: A 40-million-year history of atmospheric CO 2 . (PDF) In: The Royal Society (Philosophical Transactions A) . 371, No. 2001, September 2013. doi : 10.1098 / rsta.2013.0096 .
  16. AP Ballantyne, CB Alden, JB Miller, PP Tans, JW White: Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years. In: Nature . Volume 488, Number 7409, August 2012, pp. 70-72, ISSN  1476-4687 . doi: 10.1038 / nature11299 . PMID 22859203 .
  17. ^ Mason Inman: Carbon is forever . In: Nature Climate Change . November 2008, doi : 10.1038 / climate.2008.122 .
  18. a b c FAO study "Livestock's long shadow" 2006 .
  19. ^ Daniel F. McGinnis, Sabine Flury, Kam W. Tang, Hans-Peter Grossart: Porewater methane transport within the gas vesicles of diurnally migrating Chaoborus spp .: An energetic advantage. In: Scientific Reports. 7, 2017, doi : 10.1038 / srep44478 .
  20. Mosquito larvae surf on methane bubbles. In: March 23, 2017. Retrieved November 20, 2019 .
  21. a b c d S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, KB Averyt, M. Tignor, HL Miller (eds.): Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press , Cambridge, United Kingdom and New York, NY, USA, Chapter 2, Table 2.14. (On-line)
  22. NASA features .
  23. ^ Idw - Science Information Service. Retrieved November 18, 2016 .
  24. TF Stocker, D. Qin, G.-K. Plattner, M. Tignor, SK Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, PM Midgley (eds.): Climate Change 2013: The Physical Science Basis. Contribution of Working group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, ISBN 978-1-107-41532-4 , Chapter doi: 10.1017 / CBO9781107415324
  25. ^ A b NOAA Earth System Research Laboratory: The NOAA Annual Greenhouse Gas Index (AGGI) .
  26. S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, KB Averyt, M. Tignor, HL Miller (eds.): The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. (PDF, 3.9 MB). In: IPCC, 2007: Summary for Policymakers. In: Climate Change 2007. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
  27. Environmental Research Letters , doi: 10.1088 / 1748-9326 / 11/12/120207 . According to: , Forschungs aktuell , reports , December 12, 2016: Climate change: Methane concentrations in the atmosphere are currently increasing unusually quickly. 20th June 2017.
  28. Andrew J. Tanentzap, Amelia Fitch et al. a .: Chemical and microbial diversity covary in fresh water to influence ecosystem functioning. In: Proceedings of the National Academy of Sciences. , S. 201904896, doi : 10.1073 / pnas.1904896116 .
  29. Climate change could double greenhouse gas emissions from freshwater ecosystems. In: . November 18, 2019, accessed November 21, 2019 .
  30. Climate change could double greenhouse gas emissions from freshwater ecosystems. In: November 20, 2019, accessed November 21, 2019 .
  31. Manfred Kriener: Environmental disaster in the USA: fracking land burned down. In: August 18, 2020, accessed on August 24, 2020 .
  32. a b Nadja Podbregar: Nitrogen emissions from agriculture are also fueling climate change - nitrous oxide emissions are accelerating. In: November 19, 2019, accessed November 19, 2019 .
  33. Colin Skinner, Andreas Gattinger, Maike Krauss, Hans-Martin Krause, Jochen Mayer, Marcel GA van der Heijden, Paul Mäder: The impact of long-term organic farming on soil-derived greenhouse gas emissions. In: Scientific Reports. , February 8, 2019, accessed April 9, 2019 .
  34. TJ Blasing, Karmen Smith: Recent Greenhouse Gas Concentrations. CDIAC (Carbon Dioxide Information Analysis Center), 2012.
  35. ^ Adrian Schilt et al. a .: Glacial – interglacial and millennial-scale variations in the atmospheric nitrous oxide concentration during the last 800,000 years . In: Quaternary Science Reviews . tape 29 , no. 1–2 , October 2010, doi : 10.1016 / j.quascirev.2009.03.011 .
  36. Environment Ministry and the chemical association want to stop nitrous oxide emissions that are harmful to the climate. BMUB, September 9, 2016.
  37. Greenhouse gas emissions from the Swiss industrial sector are higher than assumed . In: Federal Office for the Environment , January 10, 2020; accessed on February 10, 2020.
  38. ^ Text of the Chemicals Climate Protection Ordinance .
  39. Hendricks: The Kigali agreement is a milestone for climate protection. October 15, 2016, accessed October 1, 2016 (press release No. 249/16).
  40. ^ SF6 Emission Reduction Partnership for the Magnesium Industry. U.S. Environmental Protection Agency, November 2, 2000, accessed September 24, 2016 .
  41. W.-T. Tsai: Environmental and health risk analysis of nitrogen trifluoride (NF 3 ), a toxic and potent greenhouse gas . In: J. Hazard. Mat. Band 159 , 2008, p. 257 , doi : 10.1016 / j.jhazmat.2008.02.023 .
  42. ^ Stefan Rahmstorf: Climate change - some facts. In: From Politics and Contemporary History . 47/2007.
  43. IPCC (Ed.): Fourth Assessment Report, Working Group I: The Physical Science Basis . 2007, ( ).
  44. a b G. Myhre u. A. Anthropogenic and Natural Radiative Foring . In: TF Stocker u. a. (Ed.): Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change . 2013, p. 661, 662, 670-672 ( [PDF; 18.5 MB ]).
  45. St. Smidt: Effects of air pollutants on plants with special consideration of forest trees ; BFW documentation 8/2008; Federal Research and Training Center for Forests, Natural Hazards and Landscape; Page 154; ( PDF file ).
  46. IPCC (Ed.): Fourth Assessment Report, Working Group I: The Physical Science Basis . 2007. , chapter ( online ).
  47. ^ Mark D. Zelinka, David A. Randal, Mark J. Webb and Stephen A. Klein: Clearing clouds of uncertainty . In: Nature Climate Change . 2017, doi : 10.1038 / nclimate3402 .
  48. O. Boucher et al. a .: Clouds and Aerosols . In: TF Stocker et al. (Ed.): Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change . 2013, Executive Summary, Chapter 7, p. 574,580 : "The sign of the net radiative feedback due to all cloud types is [...] likely positive"
  49. ^ Gunnar Myhre: Consistency Between Satellite-Derived and Modeled Estimates of the Direct Aerosol Effect . In: Science . tape 325 , July 10, 2009, p. 187–190 , doi : 10.1126 / science.1174461 .
  50. IPCC (Ed.): Fourth Assessment Report, Working Group I: The Physical Science Basis . 2007. , FAQ to Chapter 2.1, Fig. 2 ( online ).
  51. D. Shindell , G. Faluvegi: Climate response to regional radiative forcing during the twentieth century . In: Nature Geoscience . 2009, p. 294-300 , doi : 10.1038 / ngeo473 .
  52. TC Bond et al: Bounding the role of black carbon in the climate system: A scientific assessment . In: Journal of Geophysical Research . 2013, doi : 10.1002 / jgrd.50171 .
  53. Drew Shindell et al .: Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security . In: Science . 2012, doi : 10.1126 / science.1210026 .
  54. ^ MZ Jacobson : Control of fossil-fuel particulate black carbon and organic matter, possibly the most effective method of slowing global warming . In: Journal of Geophysical Research . 107 (D19), 2002, pp. 4410 , doi : 10.1029 / 2001JD001376 .
  55. ^ TC Bond, DG Streets, KF Yarber, SM Nelson, J.-H. Woo, Z. Klimont: A technology-based global inventory of black and organic carbon emissions from combustion . In: Journal of Geophysical Research . 109, D14203, 2004, doi : 10.1029 / 2003JD003697 .
  56. Oliver Reiser: The greenhouse effect from a chemical point of view. on:
  57. IPCC: Climate Change 2001: The Scientific Basis. Cambridge University Press, Cambridge (UK) 2001.
  58. The flying eco-eye. In: the daily newspaper. January 23, 2009.
  59. Greenhouse gas footprint. FOEN, April 17, 2019, accessed on May 18, 2019 .
  60. a b Intergovernmental Panel on Climate Change: IPCC Guidelines for National Greenhouse Gas Inventories . Institute for Global Environmental Strategies, Japan 2006, p. 7.
  61. a b B. Boitier: CO 2 emissions production-based accounting vs consumption: Insights from the WIOD databases (=  WIOD Conference Paper ). April 2012 ( [PDF]).
  62. a b G.P. Peters, Edgar G. Hertwich: Post-Kyoto greenhouse gas inventories: production versus consumption . In: Climatic Change . 86, 2008, pp. 51-66. doi : 10.1007 / s10584-007-9280-1 .
  63. UBA: Input-Output Tables (Switzerland). UBA, accessed on May 19, 2019 .
  64. E. G. Hertwich, G. P. Peters: Mutiregional Input-Output Database. OPEN: EU Technical Document . One planet economy network, Godalming 2010, p. 3 ( [PDF]).
  65. Reporting under the United Nations Framework Convention on Climate Change and the Kyoto Protocol 2013. (PDF; 9.6 MB). In: National inventory report on the German greenhouse gas inventory 1990–2011. Federal Environment Agency, January 15, 2013.
  66. Less greenhouse gases with less nuclear energy. Press release of the Federal Environment Agency from June 2012, p. 7. (online)
  67. Trends in greenhouse gas emissions in Germany. Federal Environment Agency, February 3, 2016, accessed on September 24, 2016 .
  68. Germany on track with 2020 climate protection targets. BMU press release of December 2, 2011. Accessed September 3, 2016.
  69. Volker Mrasek: Greenhouse gas emissions by 2020: Germany will not achieve its climate target. In: November 19, 2015, accessed September 24, 2016 .
  70. This does not include indirect emissions in upstream and downstream areas such as transport, fertilizer production, energy use. Thünen Report 65: Services of organic farming for the environment and society. In: Thünen-Institut , January 2019, accessed on January 31, 2019 .
  71. The Climate Protection Plan 2050 - The German Long-Term Climate Protection Strategy. Retrieved July 1, 2019 .
  72. a b c UBA emission data for 2015 show the need for consistent implementation of the Climate Protection 2020 action program. Federal Environment Agency and Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety, March 17, 2016, accessed on September 10, 2017 .
  73. Climate footprint 2016: Traffic and cool weather cause emissions to rise. Federal Environment Agency and Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety, March 20, 2017, accessed on September 9, 2017 .
  74. Nora Laufer: Austria misses the climate target. In: . January 29, 2019, accessed January 31, 2019 .
  75. Greenhouse gas emissions are sinking & WWF: "No reason to cheer" , ORF Teletext pages 117 and 118 on Sunday, July 28, 2019 6:33 pm
  76. Climate change: Less greenhouse gases in Austria, more emissions from traffic , Tiroler Tageszeitung, July 28, 2019, accessed on July 28, 2019
  77. Nicole Rütti: Switzerland is an environmental model pupil - but only at first glance. In: . April 9, 2019, accessed May 2, 2019 .
  78. Billions against climate change - “Switzerland has the third largest footprint in all of Europe”. In: . September 29, 2019, accessed October 1, 2019 .
  79. Federal Council wants Switzerland to be climate-neutral by 2050. In: . August 28, 2019, accessed October 2, 2019 .
  80. Greenhouse gases rise by record amount. In: The Guardian . November 4, 2011.
  81. RB Jackson et al .: Warning signs for stabilizing global CO2 emissions . In: Environmental Research Letters . tape 12 , no. 11 , 2017, doi : 10.1088 / 1748-9326 / aa9662 .
  82. ^ BP Statistical Review of World Energy, 68th edition. 2019, accessed June 23, 2019 . Table “Carbon dioxide emissions”, p. 57.
  83. ^ Jillian Ambrose: Carbon emissions from energy industry rise at the fastest rate since 2011. In: The Guardian. June 11, 2019, accessed June 23, 2019 .