This is a list of the most influential long-lived, well-mixed
greenhouse gas
A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...
es, along with their tropospheric concentrations and direct
radiative forcing
Radiative forcing (or climate forcing) is the change in energy flux in the atmosphere caused by natural or anthropogenic factors of climate change as measured by watts / metre2. It is a scientific concept used to quantify and compare the extern ...
s, as identified by the
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations. Its job is to advance scientific knowledge about climate change caused by human activities. The World Meteorological Organization (WMO) ...
(IPCC).
Abundances of these
trace gases
Trace gases are gases that are present in small amounts within an environment such as a planet's atmosphere. Trace gases in Earth's atmosphere are gases other than nitrogen (78.1%), oxygen (20.9%), and argon (0.934%) which, in combination, make ...
are regularly measured by atmospheric scientists from samples collected throughout the world. Since the 1980s, their forcing contributions (relative to year 1750) are also estimated with high accuracy using IPCC-recommended expressions derived from
radiative transfer model
An atmospheric radiative transfer model, code, or simulator calculates radiative transfer of electromagnetic radiation through a planetary atmosphere.
Methods
At the core of a radiative transfer model lies the radiative transfer equation that ...
s.
This list excludes:
*
water vapor
(99.9839 °C)
, -
, Boiling point
,
, -
, specific gas constant
, 461.5 J/( kg·K)
, -
, Heat of vaporization
, 2.27 MJ/kg
, -
, Heat capacity
, 1.864 kJ/(kg·K)
Water vapor, water vapour or aqueous vapor is the gaseous p ...
which is responsible overall for about half of all atmospheric gas forcing. Water vapor and
clouds
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid drop (liquid), droplets, ice crystals, frozen crystals, or other particulates, particles suspended in the atmosphere of a planetary body or similar space. ...
are more dynamic atmospheric constituents and contribute strong
climate change feedback
Climate change feedbacks are important in the understanding of global warming because feedback processes amplify or diminish the effect of each climate forcing, and so play an important part in determining the climate sensitivity and future cl ...
influences.
* other short-lived gases (e.g.
carbon monoxide
Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simpl ...
,
NOx) and
aerosol
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogen ...
s (e.g.
mineral dust,
black carbon
Chemically, black carbon (BC) is a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter). Black carbon consists of pure carbon in several linked forms. It is formed through the incomplete combustion of fossil fuel ...
) that also vary more strongly over location and time.
Ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the l ...
has warming influences comparable to
nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and ha ...
and
CFCs, and is longer lived and more abundant in the
stratosphere
The stratosphere () is the second layer of the atmosphere of the Earth, located above the troposphere and below the mesosphere. The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air h ...
than in the
troposphere
The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. Fro ...
.
* many
refrigerants
A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulate ...
and other
halogenated
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, ...
gases that have been mass-produced in smaller quantities. Most are long-lived and well-mixed. Some are also listed in Appendix 8A of the 2013 IPCC Assessment Report.
and Annex III of the 2021 IPCC WG1 Report
* oxygen, nitrogen, argon, and other gases that are less influenced by human activity and interact relatively little with Earth's
thermal radiation
Thermal radiation is electromagnetic radiation generated by the thermal motion of particles in matter. Thermal radiation is generated when heat from the movement of charges in the material (electrons and protons in common forms of matter) i ...
.
Combined Summary from IPCC Assessment Reports (TAR, AR4, AR5, AR6)
''
Mole fraction
In chemistry, the mole fraction or molar fraction (''xi'' or ) is defined as unit of the amount of a constituent (expressed in moles), ''ni'', divided by the total amount of all constituents in a mixture (also expressed in moles), ''n''tot. This ex ...
s: ''μmol/mol = ppm = parts per million (10
6); nmol/mol = ppb = parts per billion (10
9); pmol/mol = ppt = parts per trillion (10
12).''
The IPCC states that ''"no single atmospheric lifetime can be given"'' for CO
2.
This is mostly due to the rapid growth and cumulative magnitude of the disturbances to Earth's
carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major compon ...
by the geologic extraction and burning of fossil carbon. As of year 2014, fossil CO
2 emitted as a theoretical 10 to 100 GtC pulse on top of the existing atmospheric concentration was expected to be 50% removed by land vegetation and ocean
sinks
A sink is a bowl-shaped plumbing fixture for washing hands, dishwashing, and other purposes. Sinks have a tap (faucet) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain to ...
in less than about a century, as based on the projections of
coupled models referenced in the AR5 assessment. A substantial fraction (20-35%) was also projected to remain in the atmosphere for centuries to millennia, where fractional persistence increases with pulse size.
Values are relative to year 1750. AR6 reports the ''
effective radiative forcing'' which includes effects of rapid adjustments in the atmosphere and at the surface.
Gases from IPCC Fourth Assessment Report
The following table has its sources in Chapter 2, p. 141, Table 2.1. of the IPCC Fourth Assessment Report, Climate Change 2007 (AR4), Working Group 1 Report, The Physical Science Basis.
Gases from IPCC Third Assessment Report
The following table has its sources in Chapter 6, p. 358, Table 6.1. of the IPCC Third Assessment Report, Climate Change 2001 (TAR), Working Group 1, The Scientific Basis.
Gases relevant to radiative forcing only
Gases relevant to radiative forcing and ozone depletion
See also
*
List of refrigerants
This is a list of refrigerants, sorted by their ASHRAE-designated numbers, commonly known as R numbers. Many modern refrigerants are man-made halogenated gases, especially fluorinated gases and chlorinated gases, that are frequently referred to as ...
References
{{reflist
Greenhouse gases
Climate forcing