Greenhouse gas

greenhouse gasescarbon emissionsgreenhouse gas emissionscarbon emissiongreenhouse gas emissionemissionsGHGgreenhouse emissionsgreen house gasgreenhouse gasses
A greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range.wikipedia
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Greenhouse effect

greenhouse warminggreenhousegreenhouse gases
Greenhouse gases cause the greenhouse effect.
Radiatively active gases (i.e., greenhouse gases) in a planet's atmosphere radiate energy in all directions.

Water vapor

water vapourvaporevaporation
The primary greenhouse gases in Earth's atmosphere are water vapor (H 2 O), carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and ozone (O 3 ).
Being a component of Earth's hydrosphere and hydrologic cycle, it is particularly abundant in Earth's atmosphere where it is also a potent greenhouse gas along with other gases such as carbon dioxide and methane.

Methane

methane gasCH 4 liquid methane
The primary greenhouse gases in Earth's atmosphere are water vapor (H 2 O), carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and ozone (O 3 ). Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases (sulfur hexafluoride, hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases, and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.
The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases.

Effects of global warming

effects of climate changeimpacts of climate changeeffects
Should greenhouse gas emissions continue at their rate in 2019, global warming could cause Earth's surface temperature to exceed historical values as early as 2047, with potentially harmful effects on ecosystems, biodiversity and human livelihoods.
The effects of global warming are the environmental and social changes caused (directly or indirectly) by human emissions of greenhouse gases.

Atmosphere of Earth

airEarth's atmosphereatmosphere
The primary greenhouse gases in Earth's atmosphere are water vapor (H 2 O), carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and ozone (O 3 ).
The remaining gases are often referred to as trace gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide, and ozone.

Carbon dioxide

CO 2 CO2carbon dioxide (CO 2 )
The primary greenhouse gases in Earth's atmosphere are water vapor (H 2 O), carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and ozone (O 3 ). Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases (sulfur hexafluoride, hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases, and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.
Carbon dioxide is the most significant long-lived greenhouse gas in Earth's atmosphere.

Carbon dioxide in Earth's atmosphere

carbon dioxide emissionsatmospheric carbon dioxideCO2 emissions
Human activities since the beginning of the Industrial Revolution (around 1750) have produced a 45% increase in the atmospheric concentration of carbon dioxide, from 280 ppm in 1750 to 415 ppm in 2019.
absorbs and emits infrared radiation at wavelengths of 4.26 µm (asymmetric stretching vibrational mode) and 14.99 µm (bending vibrational mode) and consequently is a greenhouse gas that plays a significant role in influencing Earth's surface temperature through the greenhouse effect.

Atmosphere of Mars

Martian atmosphereatmosphereMars
The atmospheres of Venus, Mars and Titan also contain greenhouse gases.
The weaker greenhouse effect in the Martian atmosphere (5 °C, versus 33 °C on Earth) can be explained by the low abundance of other greenhouse gases.

Atmosphere of Venus

atmosphereVenusian atmosphereVenus
The atmospheres of Venus, Mars and Titan also contain greenhouse gases.
A runaway greenhouse effect may have been caused by the evaporation of the surface water and subsequent rise of the levels of other greenhouse gases.

Human impact on the environment

anthropogenichuman activityhuman impacts
The vast majority of anthropogenic carbon dioxide emissions come from combustion of fossil fuels, principally coal, oil, and natural gas, with additional contributions coming from deforestation, changes in land use, soil erosion and agriculture (including livestock).
Global meat consumption is projected to more than double by 2050, perhaps as much as 76%, as the global population rises to more than 9 billion, which will be a significant driver of further biodiversity loss and increased GHG emissions.

Earth

Earth's surfaceterrestrialworld
Without greenhouse gases, the average temperature of Earth's surface would be about -18 °C, rather than the present average of 15 °C.
In this model, atmospheric "greenhouse gases" kept the oceans from freezing when the newly forming Sun had only 70% of its current luminosity.

Sulfur hexafluoride

SF 6 sulphur hexafluorideSF6
In addition to the main greenhouse gases listed above, other greenhouse gases include sulfur hexafluoride, hydrofluorocarbons and perfluorocarbons (see IPCC list of greenhouse gases). Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases (sulfur hexafluoride, hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases, and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.
Sulfur hexafluoride (SF 6 ) is an inorganic, colorless, odorless, non-flammable, non-toxic but extremely potent greenhouse gas, and an excellent electrical insulator.

IPCC list of greenhouse gases

In addition to the main greenhouse gases listed above, other greenhouse gases include sulfur hexafluoride, hydrofluorocarbons and perfluorocarbons (see IPCC list of greenhouse gases).
This is a list of LLGHG (long-lived greenhouse gases) greenhouse gases as used by the IPCC TAR.

Global warming potential

global-warming potentialGWP22 times more powerful
For example, nitrogen trifluoride has a high global warming potential (GWP) but is only present in very small quantities.
Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere up to a specific time horizon, relative to carbon dioxide.

Atmospheric methane

methanemethane cyclemethane in the atmosphere
The decrease in GWP at longer times is because methane is degraded to water and through chemical reactions in the atmosphere.
Atmospheric methane concentrations are of interest because it is one of the most potent greenhouse gases in Earth's atmosphere.

Ozone

ozonationO 3 ozone generator
The primary greenhouse gases in Earth's atmosphere are water vapor (H 2 O), carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and ozone (O 3 ).
The symmetric stretch and bend are weak absorbers, but the antisymmetric stretch is strong and responsible for ozone being an important minor greenhouse gas.

Radiative forcing

climate forcingSolar Forcingclimate forcing agents
Oxidation of CO to directly produces an unambiguous increase in radiative forcing although the reason is subtle.
Radiative forcing varies with insolation, the atmospheric concentrations of radiatively active gases, commonly known as greenhouse gases, and aerosols.

Nitrogen trifluoride

NF 3
For example, nitrogen trifluoride has a high global warming potential (GWP) but is only present in very small quantities.
Nitrogen trifluoride is an extremely strong greenhouse gas.

IPCC Fourth Assessment Report

Fourth Assessment ReportAR4Fourth
The 2007 IPCC report lists the GWP as 72 over a time scale of 20 years, 25 over 100 years and 7.6 over 500 years.
The Summary for Policymakers concludes that there was a high level of agreement and much evidence that 'there is substantial economic potential for the mitigation of global greenhouse gas emissions over the coming decades, that could offset the projected growth of global emissions or reduce emissions below current levels', taking into account financial and social costs and benefits.

Haloalkane

alkyl halidealkyl halideshalogenated hydrocarbons
The phasing-out of less active HCFC-compounds will be completed in 2030.
Only haloalkanes which contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases.

Tetrafluoromethane

carbon tetrafluorideCF 4 Freon 14
Tetrafluoromethane is a useful refrigerant but also a potent greenhouse gas.

Hydroxyl radical

hydroxyl radicalsOHhydroxyl
The main chemical that reacts with methane in the atmosphere is the hydroxyl radical (OH), thus more methane means that the concentration of OH goes down.
It also has an important role in eliminating some greenhouse gases like methane and ozone.

Land use, land-use change, and forestry

LULUCFLand use, land-use change and forestryland use change
Total cumulative emissions from 1870 to 2017 were 425±20 GtC (1539 GtCO 2 ) from fossil fuels and industry, and 180±60 GtC (660 GtCO 2 ) from land use change.
Land use, land-use change, and forestry (LULUCF), also referred to as Forestry and other land use (FOLU), is defined by the United Nations Climate Change Secretariat as a "greenhouse gas inventory sector that covers emissions and removals of greenhouse gases resulting from direct human-induced land use such as settlements and commercial uses, land-use change, and forestry activities."

Radiant energy

electromagnetic energylight energyradiation
A greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range.
In geophysics, most atmospheric gases, including the greenhouse gases, allow the Sun's short-wavelength radiant energy to pass through to the Earth's surface, heating the ground and oceans.

Kyoto Protocol

Climate Change-Kyoto ProtocolKyoto AccordKyoto
Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases (sulfur hexafluoride, hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases, and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.
The Kyoto Protocol is an international treaty which extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that (part one) global warming is occurring and (part two) it is extremely likely that human-made CO 2 emissions have predominantly caused it.