Jump to content

Greenhouse gas: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
[pending revision][pending revision]
← Previous editNext edit →
Content deleted Content added
VisualWikitext
AnomieBOT (talk | contribs)
Bots
6,509,763 edits
m Dating maintenance tags: {{Citation needed}}
No edit summary
Line 2: Line 2:
[[File:The green house effect.svg|thumb|350px|right|Simple diagram of greenhouse effect.]]
[[File:The green house effect.svg|thumb|350px|right|Simple diagram of greenhouse effect.]]


A '''greenhouse gas''' (sometimes abbreviated '''GHG''') is a gas in an atmosphere that [[Absorption (electromagnetic radiation)|absorbs]] and [[Emission (electromagnetic radiation)|emits]] radiation within the [[thermal infrared]] range. This process is the fundamental cause of the [[greenhouse effect]].<ref name="IPCC AR4-SYR">{{cite web|url=http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_appendix.pdf|format=PDF|title=IPCC AR4 SYR Appendix Glossary|accessdate=14 December 2008}}</ref> The primary greenhouse gases in the [[Earth's atmosphere]] are [[water vapour]], [[carbon dioxide]], [[methane]], [[nitrous oxide]], and [[ozone]]. In the [[Solar System]], the atmospheres of [[atmosphere of Venus|Venus]], [[atmosphere of mars|Mars]], and [[Titan's atmosphere|Titan]] also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the [[Earth]]; without them, Earth's surface would average about 33&nbsp;°C (59&nbsp;°F)<ref group="note">Note that the greenhouse effect produces a temperature ''increase'' of about 33 °C (59 °F) with respect to black body predictions and not a ''surface temperature'' of 33 °C (91 °F), which is 32 °F higher. The average surface temperature is about 14 °C (57 °F).</ref> colder than at present.<ref>{{cite journal |author=Karl TR, Trenberth KE |year=2003 |title=Modern global climate change |url=http://www.sciencemag.org/cgi/content/abstract/302/5651/1719 | journal=Science |volume=302 |issue=5651 |pages=1719–23 |doi=10.1126/science.1090228 |pmid=14657489|bibcode = 2003Sci...302.1719K }}</ref><ref>{{cite book |author=Le Treut H., Somerville R., Cubasch U., Ding Y., Mauritzen C., Mokssit A., Peterson T. and Prather M.|year=2007 |url=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter1.pdf |title=Historical overview of climate change science. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M. and Miller H.L., editors) |format=PDF |publisher=Cambridge University Press |accessdate=14 December 2008}}</ref><ref name="h2o">{{cite web|url=http://nasascience.nasa.gov/earth-science/oceanography/ocean-earth-system/ocean-water-cycle |title=NASA Science Mission Directorate article on the water cycle |publisher=Nasascience.nasa.gov |date= |accessdate=2010-10-16}}</ref>
A '''greenhouse gas''' (sometimes abbreviated '''fart''') is a gas in an atmosphere that [[Absorption (electromagnetic radiation)|absorbs]] and [[Emission (electromagnetic radiation)|emits]] radiation within the [[thermal infrared]] range. This process is the fundamental cause of the [[greenhouse effect]].<ref name="IPCC AR4-SYR">{{cite web|url=http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_appendix.pdf|format=PDF|title=IPCC AR4 SYR Appendix Glossary|accessdate=14 December 2008}}</ref> The primary greenhouse gases in the [[Earth's atmosphere]] are [[water vapour]], [[carbon dioxide]], [[methane]], [[nitrous oxide]], and [[ozone]]. In the [[Solar System]], the atmospheres of [[atmosphere of Venus|Venus]], [[atmosphere of mars|Mars]], and [[Titan's atmosphere|Titan]] also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the [[Earth]]; without them, Earth's surface would average about 33&nbsp;°C (59&nbsp;°F)<ref group="note">Note that the greenhouse effect produces a temperature ''increase'' of about 33 °C (59 °F) with respect to black body predictions and not a ''surface temperature'' of 33 °C (91 °F), which is 32 °F higher. The average surface temperature is about 14 °C (57 °F).</ref> colder than at present.<ref>{{cite journal |author=Karl TR, Trenberth KE |year=2003 |title=Modern global climate change |url=http://www.sciencemag.org/cgi/content/abstract/302/5651/1719 | journal=Science |volume=302 |issue=5651 |pages=1719–23 |doi=10.1126/science.1090228 |pmid=14657489|bibcode = 2003Sci...302.1719K }}</ref><ref>{{cite book |author=Le Treut H., Somerville R., Cubasch U., Ding Y., Mauritzen C., Mokssit A., Peterson T. and Prather M.|year=2007 |url=http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter1.pdf |title=Historical overview of climate change science. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M. and Miller H.L., editors) |format=PDF |publisher=Cambridge University Press |accessdate=14 December 2008}}</ref><ref name="h2o">{{cite web|url=http://nasascience.nasa.gov/earth-science/oceanography/ocean-earth-system/ocean-water-cycle |title=NASA Science Mission Directorate article on the water cycle |publisher=Nasascience.nasa.gov |date= |accessdate=2010-10-16}}</ref>


However, since the beginning of the [[Industrial Revolution]], the burning of [[fossil fuels]] has contributed to the increase in [[Carbon dioxide in Earth's atmosphere|carbon dioxide in the atmosphere]] from 280&nbsp;ppm to 397&nbsp;ppm, despite the uptake of a large portion of the emissions through various natural "sinks" involved in the [[carbon cycle]].<ref name="cdiac">{{cite web |url=http://cdiac.ornl.gov/pns/faq.html |title=Frequently asked global change questions |publisher=[[Carbon Dioxide Information Analysis Center]]}}</ref><ref>{{cite web|author=ESRL Web Team |url=http://www.esrl.noaa.gov/gmd/ccgg/trends/ |title=Trends in carbon dioxide |publisher=Esrl.noaa.gov |date=2008-01-14 |accessdate=2011-09-11}}</ref> Anthropogenic carbon dioxide (CO<sub>2</sub>) emissions (i.e., emissions produced by human activities) come from [[combustion]] of [[carbon based fuel]]s, principally [[wood]], [[coal]], [[oil]], and [[natural gas]].<ref>Lindeburgh, Michael R., (2006). Mechanical engineering reference manual for the PE Exam. Professional Publications, Inc., Belmont, CA. ISBN 978-1-59126-049-3.</ref>
However, since the beginning of the [[Industrial Revolution]], the burning of [[fossil fuels]] has contributed to the increase in [[Carbon dioxide in Earth's atmosphere|carbon dioxide in the atmosphere]] from 280&nbsp;ppm to 397&nbsp;ppm, despite the uptake of a large portion of the emissions through various natural "sinks" involved in the [[carbon cycle]].<ref name="cdiac">{{cite web |url=http://cdiac.ornl.gov/pns/faq.html |title=Frequently asked global change questions |publisher=[[Carbon Dioxide Information Analysis Center]]}}</ref><ref>{{cite web|author=ESRL Web Team |url=http://www.esrl.noaa.gov/gmd/ccgg/trends/ |title=Trends in carbon dioxide |publisher=Esrl.noaa.gov |date=2008-01-14 |accessdate=2011-09-11}}</ref> Anthropogenic carbon dioxide (CO<sub>2</sub>) emissions (i.e., emissions produced by human activities) come from [[combustion]] of [[carbon based fuel]]s, principally [[wood]], [[coal]], [[oil]], and [[natural gas]].<ref>Lindeburgh, Michael R., (2006). Mechanical engineering reference manual for the PE Exam. Professional Publications, Inc., Belmont, CA. ISBN 978-1-59126-049-3.</ref>

Revision as of 19:16, 27 September 2012

Simple diagram of greenhouse effect.

A greenhouse gas (sometimes abbreviated fart) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.[1] The primary greenhouse gases in the Earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. In the Solar System, the atmospheres of Venus, Mars, and Titan also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth's surface would average about 33 °C (59 °F)[note 1] colder than at present.[2][3][4]

However, since the beginning of the Industrial Revolution, the burning of fossil fuels has contributed to the increase in carbon dioxide in the atmosphere from 280 ppm to 397 ppm, despite the uptake of a large portion of the emissions through various natural "sinks" involved in the carbon cycle.[5][6] Anthropogenic carbon dioxide (CO2) emissions (i.e., emissions produced by human activities) come from combustion of carbon based fuels, principally wood, coal, oil, and natural gas.[7]

Gases in Earth's atmosphere

Main articles: Greenhouse effect, Global warming, and Carbon dioxide in Earth's atmosphere

Greenhouse gases

Atmospheric absorption and scattering at different wavelengths of electromagnetic waves. The largest absorption band of carbon dioxide is in the infrared.

Greenhouse gases are those that can absorb and emit infrared radiation.[1] In order, the most abundant greenhouse gases in Earth's atmosphere are:

Atmospheric concentrations of greenhouse gases are determined by the balance between sources (emissions of the gas from human activities and natural systems) and sinks (the removal of the gas from the atmosphere by conversion to a different chemical compound).[8] The proportion of an emission remaining in the atmosphere after a specified time is the "Airborne fraction" (AF). More precisely, the annual AF is the ratio of the atmospheric increase in a given year to that year’s total emissions. For CO
2 the AF over the last 50 years (1956–2006) has been increasing at 0.25 ± 0.21%/year.[9]

Non-greenhouse gases

Although contributing to many other physical and chemical reactions, the major atmospheric constituents, nitrogen (N2), oxygen (O2), and argon (Ar), are not greenhouse gases. This is because molecules containing two atoms of the same element such as N2 and O2 and monatomic molecules such as Argon (Ar) have no net change in their dipole moment when they vibrate and hence are almost totally unaffected by infrared light. Although molecules containing two atoms of different elements such as carbon monoxide (CO) or hydrogen chloride (HCl) absorb IR, these molecules are short-lived in the atmosphere owing to their reactivity and solubility. Because they do not contribute significantly to the greenhouse effect, they are usually omitted when discussing greenhouse gases.

Non-greenhouse gases that have an indirect radiative effect

MOPITT 2000 global carbon monoxide.

Carbon monoxide has an indirect radiative effect by elevating concentrations of methane and tropospheric ozone through scavenging of atmospheric constituents (e.g., the hydroxyl radical, OH) that would otherwise destroy them. Carbon monoxide is created when carbon-containing fuels are burned incompletely. Through natural processes in the atmosphere, it is eventually oxidized to carbon dioxide. Carbon monoxide has an atmospheric lifetime of only a few months[10] and as a consequence is spatially more variable than longer-lived gases.

Contribution of clouds to Earth's greenhouse effect

The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the greenhouse gases. Clouds are water droplets or ice crystals suspended in the atmosphere.[11][12]

Impact of a given gas on the overall greenhouse effect

The contribution of each gas to the greenhouse effect is affected by the characteristics of that gas, its abundance, and any indirect effects it may cause. For example, on a molecule-for-molecule basis the direct radiative effects of methane is about 72 times stronger than carbon dioxide over a 20 year time frame[13] but it is present in much smaller concentrations so that its total direct radiative effect is smaller, and it has a shorter atmospheric lifetime. On the other hand, in addition to its direct radiative impact methane has a large indirect radiative effect because it contributes to ozone formation. Shindell et al. (2005)[14] argue that the contribution to climate change from methane is at least double previous estimates as a result of this effect.[15]

When these gases are ranked by their direct contribution to the greenhouse effect, the most important are:[11]

Gas
  		Formula
  		Contribution
(%)
Water vapor H2O 36 – 72 %  
Carbon dioxide CO2 9 – 26 %
Methane CH4 4 – 9 %  
Ozone O3 3 – 7 %  

In addition to the main greenhouse gases listed above, other greenhouse gases include sulfur hexafluoride, hydrofluorocarbons and perfluorocarbons (see IPCC list of greenhouse gases). Some greenhouse gases are not often listed. For example, nitrogen trifluoride has a high global warming potential (GWP) but is only present in very small quantities.[16]

Proportion of direct effects at a given moment

It is not possible to state that a certain gas causes an exact percentage of the greenhouse effect. This is because some of the gases absorb and emit radiation at the same frequencies as others, so that the total greenhouse effect is not simply the sum of the influence of each gas. The higher ends of the ranges quoted are for each gas alone; the lower ends account for overlaps with the other gases.[11][12] In addition, some gases such as methane are known to have large indirect effects that are still being quantified.[17]

Atmospheric lifetime

Aside from water vapor, which has a residence time of about nine days,[18] major greenhouse gases are well-mixed, and take many years to leave the atmosphere.[19] Although it is not easy to know with precision how long it takes greenhouse gases to leave the atmosphere, there are estimates for the principal greenhouse gases. Jacob (1999)[20] defines the lifetime of an atmospheric species X in a one-box model as the average time that a molecule of X remains in the box. Mathematically can be defined as the ratio of the mass (in kg) of X in the box to its removal rate, which is the sum of the flow of X out of the box (), chemical loss of X (), and deposition of X () (all in kg/sec): .[20] If one stopped pouring any of this gas into the box, then after a time , its concentration would be about halved.

The atmospheric lifetime of a species therefore measures the time required to restore equilibrium following a sudden increase or decrease in its concentration in the atmosphere. Individual atoms or molecules may be lost or deposited to sinks such as the soil, the oceans and other waters, or vegetation and other biological systems, reducing the excess to background concentrations. The average time taken to achieve this is the mean lifetime.

Carbon dioxide has a variable atmospheric lifetime, and cannot be specified precisely.[21] The atmospheric lifetime of CO
2 is estimated of the order of 30–95 years.[22] This figure accounts for CO
2 molecules being removed from the atmosphere by mixing into the ocean, photosynthesis, and a few other processes. However, this excludes the balancing fluxes of CO
2 into the atmosphere from the geological reservoirs, which have slower characteristic rates.[23] While more than half of the CO
2 emitted is currently removed from the atmosphere within a century, some fraction (about 20%) of emitted CO
2 remains in the atmosphere for many thousands of years.[24][25][26]

Radiative forcing

When energy from the sun reaches the Earth, the planet absorbs some of this energy and radiates the rest back to space as heat.[27] The Earth's surface temperature depends on this balance between incoming and outgoing energy.[27] If this energy balance is shifted, the Earth's surface could become noticeably warmer or cooler, leading to a variety of changes in global climate.[27]

A number of natural and man-made mechanisms can affect the global energy balance and force changes in the Earth's climate.[27] Greenhouse gases are one such mechanism.[27] Greenhouse gases in the atmosphere absorb and re-emit some of the outgoing energy radiated from the Earth's surface, causing that heat to be retained in the lower atmosphere.[27] As explained above, some greenhouse gases remain in the atmosphere for decades or even centuries, and therefore can affect the Earth's energy balance over a long time period.[27] Factors that influence Earth's energy balance can be quantified in terms of "radiative climate forcing."[27] Positive radiative forcing indicates warming (for example, by increasing incoming energy or decreasing the amount of energy that escapes to space), while negative forcing is associated with cooling.[27]

Global warming potential

The global warming potential (GWP) depends on both the efficiency of the molecule as a greenhouse gas and its atmospheric lifetime. GWP is measured relative to the same mass of CO
2 and evaluated for a specific timescale. Thus, if a gas has a high (positive) radiative forcing but also a short lifetime, it will have a large GWP on a 20 year scale but a small one on a 100 year scale. Conversely, if a molecule has a longer atmospheric lifetime than CO2 its GWP will increase with the timescale considered. Carbon dioxide is defined to have a GWP of 1 over all time periods.

Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 72 over 20 years, 25 over 100 years and 7.6 over 500 years. The decrease in GWP at longer times is because methane is degraded to water and CO2 through chemical reactions in the atmosphere.

Examples of the atmospheric lifetime and GWP relative to CO2 for several greenhouse gases are given in the following table:[13]

Atmospheric lifetime and GWP relative to CO2 at different time horizon for various greenhouse gases.
Gas name Chemical
formula		 Lifetime
(years) 		Global warming potential (GWP) for given time horizon
20-yr 100-yr 500-yr
Carbon dioxide CO2 See above 1 1 1
Methane CH4 12 72 25 7.6
Nitrous oxide N2O 114 289 298 153
CFC-12 CCl2F2 100 11 000 10 900 5 200
HCFC-22 CHClF2 12 5 160 1 810 549
Tetrafluoromethane CF4 50 000 5 210 7 390 11 200
Hexafluoroethane C2F6 10 000 8 630 12 200 18 200
Sulphur hexafluoride SF6 3 200 16 300 22 800 32 600
Nitrogen trifluoride NF3 740 12 300 17 200 20 700

The use of CFC-12 (except some essential uses) has been phased out due to its ozone depleting properties.[28] The phasing-out of less active HCFC-compounds will be completed in 2030.[29]

Natural and anthropogenic sources

400,000 years of ice core data.
Top: Increasing atmospheric carbon dioxide levels as measured in the atmosphere and reflected in ice cores. Bottom: The amount of net carbon increase in the atmosphere, compared to carbon emissions from burning fossil fuel.

Aside from purely human-produced synthetic halocarbons, most greenhouse gases have both natural and human-caused sources. During the pre-industrial Holocene, concentrations of existing gases were roughly constant. In the industrial era, human activities have added greenhouse gases to the atmosphere, mainly through the burning of fossil fuels and clearing of forests.[30][31]

The 2007 Fourth Assessment Report compiled by the IPCC (AR4) noted that "changes in atmospheric concentrations of greenhouse gases and aerosols, land cover and solar radiation alter the energy balance of the climate system", and concluded that "increases in anthropogenic greenhouse gas concentrations is very likely to have caused most of the increases in global average temperatures since the mid-20th century".[32] In AR4, "most of" is defined as more than 50%.

Gas Preindustrial level
[citation needed] 		Current level  
[citation needed] 		Increase since 1750  
[citation needed] 		Radiative forcing (W/m2)
[citation needed]
Carbon dioxide 280 ppm  396 ppm 116 ppm 1.46
Methane 700 ppb 1745 ppb 1045 ppb  0.48
Nitrous oxide 270 ppb  314 ppb  44 ppb 0.15
CFC-12 0  533 ppt 533 ppt 0.17
Relevant to both radiative forcing and ozone depletion; all of the following have no natural sources and hence zero amounts pre-industrial
Gas Current (1998)
Amount by volume 		Radiative forcing
(W/m2)
CFC-11 268 ppt 0.07
CFC-12 533 ppt 0.17
CFC-113  84 ppt 0.03
Carbon tetrachloride 102 ppt 0.01
HCFC-22  69 ppt 0.03

(Source: IPCC radiative forcing report 1994 updated (to 1998) by IPCC TAR table 6.1[33][34] ).

Ice cores provide evidence for variation in greenhouse gas concentrations over the past 800,000 years (see the following section). Both CO
2 and CH
4 vary between glacial and interglacial phases, and concentrations of these gases correlate strongly with temperature. Direct data does not exist for periods earlier than those represented in the ice core record, a record that indicates CO
2 mole fractions stayed within a range of 180 ppm to 280 ppm throughout the last 800,000 years, until the increase of the last 250 years. However, various proxies and modeling suggests larger variations in past epochs; 500 million years ago CO
2 levels were likely 10 times higher than now.[35] Indeed higher CO
2 concentrations are thought to have prevailed throughout most of the Phanerozoic eon, with concentrations four to six times current concentrations during the Mesozoic era, and ten to fifteen times current concentrations during the early Palaeozoic era until the middle of the Devonian period, about 400 Ma.[36][37][38] The spread of land plants is thought to have reduced CO
2 concentrations during the late Devonian, and plant activities as both sources and sinks of CO
2 have since been important in providing stabilising feedbacks.[39] Earlier still, a 200-million year period of intermittent, widespread glaciation extending close to the equator (Snowball Earth) appears to have been ended suddenly, about 550 Ma, by a colossal volcanic outgassing that raised the CO
2 concentration of the atmosphere abruptly to 12%, about 350 times modern levels, causing extreme greenhouse conditions and carbonate deposition as limestone at the rate of about 1 mm per day.[40] This episode marked the close of the Precambrian eon, and was succeeded by the generally warmer conditions of the Phanerozoic, during which multicellular animal and plant life evolved. No volcanic carbon dioxide emission of comparable scale has occurred since. In the modern era, emissions to the atmosphere from volcanoes are only about 1% of emissions from human sources.[40][41]

Ice cores

Measurements from Antarctic ice cores show that before industrial emissions started atmospheric CO2 mole fractions were about 280 parts per million (ppm), and stayed between 260 and 280 during the preceding ten thousand years.[42] Carbon dioxide mole fractions in the atmosphere have gone up by approximately 35 percent since the 1900s, rising from 280 parts per million by volume to 387 parts per million in 2009. One study using evidence from stomata of fossilized leaves suggests greater variability, with carbon dioxide mole fractions above 300 ppm during the period seven to ten thousand years ago,[43] though others have argued that these findings more likely reflect calibration or contamination problems rather than actual CO2 variability.[44][45] Because of the way air is trapped in ice (pores in the ice close off slowly to form bubbles deep within the firn) and the time period represented in each ice sample analyzed, these figures represent averages of atmospheric concentrations of up to a few centuries rather than annual or decadal levels.

Changes since the Industrial Revolution

Recent year-to-year increase of atmospheric CO2.
Major greenhouse gas trends.

Since the beginning of the Industrial Revolution, the concentrations of most of the greenhouse gases have increased. For example, the mole fraction of carbon dioxide has increased from 280 ppm by about 36% to 380 ppm, or 100 ppm over modern pre-industrial levels. The first 50 ppm increase took place in about 200 years, from the start of the Industrial Revolution to around 1973; however the next 50 ppm increase took place in about 33 years, from 1973 to 2006.[46]

Recent data also shows that the concentration is increasing at a higher rate. In the 1960s, the average annual increase was only 37% of what it was in 2000 through 2007.[47]

Today, the stock of carbon in the atmosphere increases by more than 3 million tonnes per annum (0.04%) compared with the existing stock.[clarification needed] This increase is the result of human activities by burning fossil fuels, deforestation and forest degradation in tropical and boreal regions.[48]

The other greenhouse gases produced from human activity show similar increases in both amount and rate of increase. Many observations are available online in a variety of Atmospheric Chemistry Observational Databases.

Anthropogenic greenhouse gases

This graph shows changes in the annual greenhouse gas index (AGGI) between 1979 and 2008.[49] The AGGI measures the levels of greenhouse gases in the atmosphere based on their ability to cause changes in the Earth's climate.[49]
This bar graph shows global greenhouse gas emissions by sector from 1990 to 2005, measured in carbon dioxide equivalents.[50]
Modern global anthropogenic carbon emissions.

Since about 1750 human activity has increased the concentration of carbon dioxide and other greenhouse gases. Measured atmospheric concentrations of carbon dioxide are currently 100 ppm higher than pre-industrial levels.[51] Natural sources of carbon dioxide are more than 20 times greater than sources due to human activity,[52] but over periods longer than a few years natural sources are closely balanced by natural sinks, mainly photosynthesis of carbon compounds by plants and marine plankton. As a result of this balance, the atmospheric mole fraction of carbon dioxide remained between 260 and 280 parts per million for the 10,000 years between the end of the last glacial maximum and the start of the industrial era.[53]

It is likely that anthropogenic (i.e., human-induced) warming, such as that due to elevated greenhouse gas levels, has had a discernible influence on many physical and biological systems.[54] Future warming is projected to have a range of impacts, including sea level rise,[55] increased frequencies and severities of some extreme weather events,[55] loss of biodiversity,[56] and regional changes in agricultural productivity.[56]

The main sources of greenhouse gases due to human activity are:

  • burning of fossil fuels and deforestation leading to higher carbon dioxide concentrations in the air. Land use change (mainly deforestation in the tropics) account for up to one third of total anthropogenic CO
    2     emissions.[53]
  • livestock enteric fermentation and manure management,[57] paddy rice farming, land use and wetland changes, pipeline losses, and covered vented landfill emissions leading to higher methane atmospheric concentrations. Many of the newer style fully vented septic systems that enhance and target the fermentation process also are sources of atmospheric methane.
  • use of chlorofluorocarbons (CFCs) in refrigeration systems, and use of CFCs and halons in fire suppression systems and manufacturing processes.
  • agricultural activities, including the use of fertilizers, that lead to higher nitrous oxide (N2O) concentrations.

The seven sources of CO
2 from fossil fuel combustion are (with percentage contributions for 2000–2004):[58]

Seven main fossil fuel
combustion sources		 Contribution
(%)
Liquid fuels (e.g., gasoline, fuel oil) 36 %
Solid fuels (e.g., coal) 35 %
Gaseous fuels (e.g., natural gas) 20 %
Cement production  3 %
Flaring gas industrially and at wells < 1 %  
Non-fuel hydrocarbons < 1 %  
"International bunker fuels" of transport
not included in national inventories		  4 %

Carbon dioxide, methane, nitrous oxide (N
2O) and three groups of fluorinated gases (sulfur hexafluoride (SF
6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases,[59]: 147 [60] and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.[61] Emissions limitations specified in the Kyoto Protocol expire in 2012.[61] The Cancún agreement, agreed in 2010, includes voluntary pledges made by 76 countries to control emissions.[62] At the time of the agreement, these 76 countries were collectively responsible for 85% of annual global emissions.[62]

Although CFCs are greenhouse gases, they are regulated by the Montreal Protocol, which was motivated by CFCs' contribution to ozone depletion rather than by their contribution to global warming. Note that ozone depletion has only a minor role in greenhouse warming though the two processes often are confused in the media.

Role of water vapor

Increasing water vapor in the stratosphere at Boulder, Colorado.

Water vapor accounts for the largest percentage of the greenhouse effect, between 36% and 66% for clear sky conditions and between 66% and 85% when including clouds.[12] Water vapor concentrations fluctuate regionally, but human activity does not significantly affect water vapor concentrations except at local scales, such as near irrigated fields. The atmospheric concentration of vapor is highly variable, from less than 0.01% in extremely cold regions up to 20% in warm, humid regions.[63]

The average residence time of a water molecule in the atmosphere is only about nine days, compared to years or centuries for other greenhouse gases such as CH4 and CO2.[64] Thus, water vapor responds to and amplifies effects of the other greenhouse gases. The Clausius-Clapeyron relation establishes that air can hold more water vapor per unit volume when it warms. This and other basic principles indicate that warming associated with increased concentrations of the other greenhouse gases also will increase the concentration of water vapor. Because water vapor is a greenhouse gas, this results in further warming and so is a "positive feedback" that amplifies the original warming. Eventually other earth processes offset these positive feedbacks, stabilizing the global temperature at a new equilibrium and preventing the loss of Earth's water through a Venus-like runaway greenhouse effect.[65]

Greenhouse gas emissions ("sources")

Between the period 1970 to 2004, GHG emissions (measured in CO
2-equivalent)[66] increased at an average rate of 1.6% per year, with CO2 emissions from the use of fossil fuels growing at a rate of 1.9% per year.[67][68] Total anthropogenic emissions at the end of 2009 were estimated at 49.5 gigatonnes CO
2-equivalent.[69]: 15  These emissions include CO
2 from fossil fuel use and from land use, as well as emissions of methane, nitrous oxide and other GHGs covered by the Kyoto Protocol.

At present, the two primary sources of CO2 emissions are from burning coal used for electricity generation and petroleum used for motor transport.[citation needed]

Regional and national attribution of emissions

See also: Kyoto Protocol and government action

There are several different ways of measuring GHG emissions, for example, see World Bank (2010)[70]: 362  for tables of national emissions data. Some variables that have been reported[71] include:

  • Definition of measurement boundaries: Emissions can be attributed geographically, to the area where they were emitted (the territory principle) or by the activity principle to the territory produced the emissions. These two principles result in different totals when measuring, for example, electricity importation from one country to another, or emissions at an international airport.
  • Time horizon of different GHGs: Contribution of a given GHG is reported as a CO2 equivalent. The calculation to determine this takes into account how long that gas remains in the atmosphere. This is not always known accurately and calculations must be regularly updated to reflect new information.
  • What sectors are included in the calculation (e.g., energy industries, industrial processes, agriculture etc.): There is often a conflict between transparency and availability of data.
  • The measurement protocol itself: This may be via direct measurement or estimation. The four main methods are the emission factor-based method, mass balance method, predictive emissions monitoring system, and continuing emissions monitoring systems. These methods differ in accuracy, cost, and usability.

These different measures are sometimes used by different countries to assert various policy/ethical positions on climate change (Banuri et al., 1996, p. 94).[72] This use of different measures leads to a lack of comparability, which is problematic when monitoring progress towards targets. There are arguments for the adoption of a common measurement tool, or at least the development of communication between different tools.[71]

Emissions may be measured over long time periods. This measurement type is called historical or cumulative emissions. Cumulative emissions give some indication of who is responsible for the build-up in the atmospheric concentration of GHGs (IEA, 2007, p. 199).[73]

The national accounts balance would be positively related to carbon emissions. The national accounts balance shows the difference between exports and imports. For many richer nations, such as the United States, the accounts balance is negative because more goods are imported than they are exported. This is mostly due to the fact that it is cheaper to produce goods outside of developed countries, leading the economies of developed countries to become increasingly dependent on services and not goods. We believed that a positive accounts balance would means that more production was occurring in a country, so more factories working would increase carbon emission levels.(Holtz-Eakin, 1995, pp.;85;101).[74]

Emissions may also be measured across shorter time periods. Emissions changes may, for example, be measured against a base year of 1990. 1990 was used in the United Nations Framework Convention on Climate Change (UNFCCC) as the base year for emissions, and is also used in the Kyoto Protocol (some gases are also measured from the year 1995).[59]: 146, 149  A country's emissions may also be reported as a proportion of global emissions for a particular year.

Another measurement is of per capita emissions. This divides a country's total annual emissions by its mid-year population.[70]: 370  Per capita emissions may be based on historical or annual emissions (Banuri et al., 1996, pp. 106–107).[72]

Greenhouse gas intensity and land-use change

Greenhouse gas intensity in the year 2000, including land-use change.
Cumulative energy-related CO
2 emissions between the years 1850-2005 grouped into low-income, middle-income, high-income, the EU-15, and the OECD countries.
Cumulative energy-related CO
2 emissions between the years 1850-2005 for individual countries.
Map of cumulative per capita anthropogenic atmospheric CO
2 emissions by country. Cumulative emissions include land use change, and are measured between the years 1950 and 2000.
Regional trends in annual CO
2 emissions from fuel combustion between 1971 and 2009.
Regional trends in annual per capita CO
2 emissions from fuel combustion between 1971 and 2009.

The first figure shown opposite is based on data from the World Resources Institute, and shows a measurement of GHG emissions for the year 2000 according to greenhouse gas intensity and land-use change. Herzog et al. (2006, p. 3) defined greenhouse gas intensity as GHG emissions divided by economic output.[75] GHG intensities are subject to uncertainty over whether they are calculated using market exchange rates (MER) or purchasing power parity (PPP) (Banuri et al., 1996, p. 96).[72] Calculations based on MER suggest large differences in intensities between developed and developing countries, whereas calculations based on PPP show smaller differences.

Land-use change, e.g., the clearing of forests for agricultural use, can affect the concentration of GHGs in the atmosphere by altering how much carbon flows out of the atmosphere into carbon sinks.[76] Accounting for land-use change can be understood as an attempt to measure “net” emissions, i.e., gross emissions from all GHG sources minus the removal of emissions from the atmosphere by carbon sinks (Banuri et al., 1996, pp. 92–93).[72]

There are substantial uncertainties in the measurement of net carbon emissions.[77] Additionally, there is controversy over how carbon sinks should be allocated between different regions and over time (Banuri et al., 1996, p. 93).[72] For instance, concentrating on more recent changes in carbon sinks is likely to favour those regions that have deforested earlier, e.g., Europe.

Cumulative and historical emissions

Cumulative anthropogenic (i.e., human-emitted) emissions of CO
2 from fossil fuel use are a major cause of global warming,[78] and give some indication of which countries have contributed most to human-induced climate change.[79]: 15 

Top-5 historic CO2 contributors by region over the years 1800 to 1988 (in %)
Region Industrial
CO2 		Total
CO2
OECD North America 33.2 29.7
OECD Europe 26.1 16.6
Former USSR 14.1 12.5
China   5.5   6.0
Eastern Europe   5.5   4.8

The table above to the left is based on Banuri et al. (1996, p. 94).[72] Overall, developed countries accounted for 83.8% of industrial CO2 emissions over this time period, and 67.8% of total CO2 emissions. Developing countries accounted for industrial CO2 emissions of 16.2% over this time period, and 32.2% of total CO2 emissions. The estimate of total CO2 emissions includes biotic carbon emissions, mainly from deforestation. Banuri et al. (1996, p. 94)[72] calculated per capita cumulative emissions based on then-current population. The ratio in per capita emissions between industrialized countries and developing countries was estimated at more than 10 to 1.

Including biotic emissions brings about the same controversy mentioned earlier regarding carbon sinks and land-use change (Banuri et al., 1996, pp. 93–94).[72] The actual calculation of net emissions is very complex, and is affected by how carbon sinks are allocated between regions and the dynamics of the climate system.

Non-OECD countries accounted for 42% of cumulative energy-related CO
2 emissions between 1890-2007.[80]: 179–180  Over this time period, the US accounted for 28% of emissions; the EU, 23%; Russia, 11%; China, 9%; other OECD countries, 5%; Japan, 4%; India, 3%; and the rest of the world, 18%.[80]: 179–180 

Changes since a particular base year

See also: Kyoto Protocol § Government action and emissions

Between 1970-2004, global growth in annual CO
2 emissions was driven by North America, Asia, and the Middle East.[81] The sharp acceleration in CO2 emissions since 2000 to more than a 3% increase per year (more than 2 ppm per year) from 1.1% per year during the 1990s is attributable to the lapse of formerly declining trends in carbon intensity of both developing and developed nations. China was responsible for most of global growth in emissions during this period. Localised plummeting emissions associated with the collapse of the Soviet Union have been followed by slow emissions growth in this region due to more efficient energy use, made necessary by the increasing proportion of it that is exported.[58] In comparison, methane has not increased appreciably, and N2O by 0.25% y−1.

Using different base years for measuring emissions has an effect on estimates of national contributions to global warming.[79]: 17–18 [82] This can be calculated by dividing a country's highest contribution to global warming starting from a particular base year, by that country's minimum contribution to global warming starting from a particular base year. Choosing between different base years of 1750, 1900, 1950, and 1990 has a significant effect for most countries.[79]: 17–18  Within the G8 group of countries, it is most significant for the UK, France and Germany. These countries have a long history of CO
2 emissions (see the section on Cumulative and historical emissions).

Annual emissions

Per capita anthropogenic greenhouse gas emissions by country for the year 2000 including land-use change.

Annual per capita emissions in the industrialized countries are typically as much as ten times the average in developing countries.[59]: 144  Due to China's fast economic development, its annual per capita emissions are quickly approaching the levels of those in the Annex I group of the Kyoto Protocol (i.e., the developed countries excluding the USA).[83] Other countries with fast growing emissions are South Korea, Iran, and Australia. On the other hand, annual per capita emissions of the EU-15 and the USA are gradually decreasing over time.[83] Emissions in Russia and the Ukraine have decreased fastest since 1990 due to economic restructuring in these countries.[84]

Energy statistics for fast growing economies are less accurate than those for the industrialized countries. For China's annual emissions in 2008, the Netherlands Environmental Assessment Agency estimated an uncertainty range of about 10%.[83]

Top emitters

Bar graph of annual per capita CO
2 emissions from fuel combustion for 140 countries in 2009.
Bar graph of cumulative energy-related per capita CO
2 emissions between 1850-2008 for 185 countries.
See also: List of countries by carbon dioxide emissions, List of countries by carbon dioxide emissions per capita, List of countries by greenhouse gas emissions, and List of countries by greenhouse gas emissions per capita

Annual

In 2009, the annual top ten emitting countries accounted for about two-thirds of the world's annual energy-related CO
2 emissions.[85]

Top-10 annual energy-related CO
2 emitters for the year 2009[86]
Country % of global total
annual emissions 		Tonnes of GHG
per capita
People's Rep. of China 23.6 5.13
United States 17.9 16.9
India 5.5 1.37
Russian Federation 5.3 10.8
Japan 3.8 8.6
Germany 2.6 9.2
Islamic Rep. of Iran 1.8 7.3
Canada 1.8 15.4
Korea 1.8 10.6
United Kingdom 1.6 7.5

Cumulative

Top-10 cumulative energy-related CO
2 emitters between 1850-2008[87]
Country % of world
total 		Metric tonnes
CO
2 per person
United States 28.5 1,132.7
China 9.36 85.4
Russian Federation 7.95 677.2
Germany 6.78 998.9
United Kingdom 5.73 1,127.8
Japan 3.88 367
France 2.73 514.9
India 2.52 26.7
Canada 2.17 789.2
Ukraine 2.13 556.4

Embedded emissions

One way of attributing greenhouse gas (GHG) emissions is to measure the embedded emissions (also referred to as "embodied emissions") of goods that are being consumed. Emissions are usually measured according to production, rather than consumption.[88] For example, in the main international treaty on climate change (the UNFCCC), countries report on emissions produced within their borders, e.g., the emissions produced from burning fossil fuels.[80]: 179 [89]: 1  Under a production-based accounting of emissions, embedded emissions on imported goods are attributed to the exporting, rather than the importing, country. Under a consumption-based accounting of emissions, embedded emissions on imported goods are attributed to the importing country, rather than the exporting, country.

Davis and Caldeira (2010)[89]: 4  found that a substantial proportion of CO2 emissions are traded internationally. The net effect of trade was to export emissions from China and other emerging markets to consumers in the US, Japan, and Western Europe. Based on annual emissions data from the year 2004, and on a per-capita consumption basis, the top-5 emitting countries were found to be (in tCO2 per person, per year): Luxembourg (34.7), the US (22.0), Singapore (20.2), Australia (16.7), and Canada (16.6).[89]: 5 

Effect of policy

See also: Kyoto Protocol and government action

Governments have taken action to reduce GHG emissions (climate change mitigation). Assessments of policy effectiveness have included work by the Intergovernmental Panel on Climate Change,[90] International Energy Agency,[91][92] and United Nations Environment Programme.[93] Policies implemented by governments have included[94][95][96] national and regional targets to reduce emissions, promoting energy efficiency, and support for renewable energy.

Countries and regions listed in Annex I of the United Nations Framework Convention on Climate Change (UNFCCC) (i.e., the OECD and former planned economies of the Soviet Union) are required to submit periodic assessments to the UNFCCC of actions they are taking to address climate change.[96]: 3  Analysis by the UNFCCC (2011)[96]: 8  suggested that policies and measures undertaken by Annex I Parties may have produced emission savings of 1.5 thousand Tg CO
2-eq in the year 2010, with most savings made in the energy sector. The projected emissions saving of 1.5 thousand Tg CO
2-eq is measured against a hypothetical "baseline" of Annex I emissions, i.e., projected Annex I emissions in the absence of policies and measures. The total projected Annex I saving of 1.5 thousand CO
2-eq does not include emissions savings in seven of the Annex I Parties.[96]: 8 

Projections

Further information: climate change scenario § Quantitative emissions projections
See also: Global climate model § Projections of future climate change

A wide range of projections of future GHG emissions have been produced.[97] Rogner et al. (2007)[98] assessed the scientific literature on GHG projections. Rogner et al. (2007)[67] concluded that unless energy policies changed substantially, the world would continue to depend on fossil fuels until 2025-2030. Projections suggest that more than 80% of the world's energy will come from fossil fuels. This conclusion was based on "much evidence" and "high agreement" in the literature.[67] Projected annual energy-related CO
2 emissions in 2030 were 40-110% higher than in 2000, with two-thirds of the increase originating in developing countries.[67] Projected annual per capita emissions in developed country regions remained substantially lower (2.8-5.1 tonnes CO
2) than those in developed country regions (9.6-15.1 tonnes CO
2).[99] Projections consistently showed increase in annual world GHG emissions (the "Kyoto" gases,[100] measured in CO
2-equivalent) of 25-90% by 2030, compared to 2000.[67]

Relative CO2 emission from various fuels

One liter of gasoline, when used as a fuel, produces 2.32 kg (about 1300 liters or 1.3 cubic meters) of carbon dioxide, a greenhouse gas. One US gallon produces 19.4 lb (1,291.5 gallons or 172.65 cubic feet)[101][102][103]

Mass of carbon dioxide emitted per quantity of energy for various fuels[104]
Fuel name CO2
emitted
(lbs/106 Btu) 		CO2
emitted
(g/106 J)
Natural gas 117 50.30
Liquefied petroleum gas 139 59.76
Propane 139 59.76
Aviation gasoline 153 65.78
Automobile gasoline 156 67.07
Kerosene 159 68.36
Fuel oil 161 69.22
Tires/tire derived fuel 189 81.26
Wood and wood waste 195 83.83
Coal (bituminous) 205 88.13
Coal (sub-bituminous) 213 91.57
Coal (lignite) 215 92.43
Petroleum coke 225 96.73
Coal (anthracite) 227 97.59

Removal from the atmosphere ("sinks")

Natural processes

Greenhouse gases can be removed from the atmosphere by various processes, as a consequence of:

  • a physical change (condensation and precipitation remove water vapor from the atmosphere).
  • a chemical reaction within the atmosphere. For example, methane is oxidized by reaction with naturally occurring hydroxyl radical, OH· and degraded to CO
    2     and water vapor (CO
    2     from the oxidation of methane is not included in the methane Global warming potential). Other chemical reactions include solution and solid phase chemistry occurring in atmospheric aerosols.
  • a physical exchange between the atmosphere and the other compartments of the planet. An example is the mixing of atmospheric gases into the oceans.
  • a chemical change at the interface between the atmosphere and the other compartments of the planet. This is the case for CO
    2    , which is reduced by photosynthesis of plants, and which, after dissolving in the oceans, reacts to form carbonic acid and bicarbonate and carbonate ions (see ocean acidification).
  • a photochemical change. Halocarbons are dissociated by UV light releasing Cl· and F· as free radicals in the stratosphere with harmful effects on ozone (halocarbons are generally too stable to disappear by chemical reaction in the atmosphere).

Negative emissions

See also: Bio-energy with carbon capture and storage, Carbon dioxide air capture, Geoengineering, and Greenhouse gas remediation

A number of technologies remove greenhouse gases emissions from the atmosphere. Most widely analysed are those that remove carbon dioxide from the atmosphere, either to geologic formations such as bio-energy with carbon capture and storage[105][106][107] and carbon dioxide air capture,[107] or to the soil as in the case with biochar.[107] The IPCC has pointed out that many long-term climate scenario models require large scale manmade negative emissions to avoid serious climate change.[108]

History of scientific research

Late 19th century scientists experimentally discovered that N
2 and O
2 do not absorb infrared radiation (called, at that time, "dark radiation") while, on the contrary, water, both as true vapour and condensed in the form of microscopic droplets suspended in clouds, as well as CO2 and other poly-atomic gaseous molecules, do absorb infrared radiation. It was recognized in the early 20th century that greenhouse gases in the atmosphere made the Earth's overall temperature higher than it would be without them. During the late 20th century, a scientific consensus evolved that increasing concentrations of greenhouse gases in the atmosphere are causing a substantial rise in global temperatures and changes to other parts of the climate system, with consequences for the environment and for human health.[109]

Environmental Portal

See also

3

Notes

  1. ^ Note that the greenhouse effect produces a temperature increase of about 33 °C (59 °F) with respect to black body predictions and not a surface temperature of 33 °C (91 °F), which is 32 °F higher. The average surface temperature is about 14 °C (57 °F).

References

  1. ^ a b "IPCC AR4 SYR Appendix Glossary" (PDF). Retrieved 14 December 2008.
  2. ^ Karl TR, Trenberth KE (2003). "Modern global climate change". Science. 302 (5651): 1719–23. Bibcode:2003Sci...302.1719K. doi:10.1126/science.1090228. PMID 14657489.
  3. ^ Le Treut H., Somerville R., Cubasch U., Ding Y., Mauritzen C., Mokssit A., Peterson T. and Prather M. (2007). Historical overview of climate change science. In: Climate change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M. and Miller H.L., editors) (PDF). Cambridge University Press. Retrieved 14 December 2008.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. ^ "NASA Science Mission Directorate article on the water cycle". Nasascience.nasa.gov. Retrieved 16 October 2010.
  5. ^ "Frequently asked global change questions". Carbon Dioxide Information Analysis Center.
  6. ^ ESRL Web Team (14 January 2008). "Trends in carbon dioxide". Esrl.noaa.gov. Retrieved 11 September 2011.
  7. ^ Lindeburgh, Michael R., (2006). Mechanical engineering reference manual for the PE Exam. Professional Publications, Inc., Belmont, CA. ISBN 978-1-59126-049-3.
  8. ^ IPCC (2007). "Chapter 7: Couplings Between Changes in the Climate System and Biogeochemistry" (PDF). IPCC WG1 AR4 Report. IPCC. p. FAQ 7.1; report page 512; pdf page 14. Retrieved 11 July 2011.
  9. ^ Canadell, J.G. (2007). "Contributions to accelerating atmospheric CO
    2     growth from economic activity, carbon intensity, and efficiency of natural sinks"    . Proc. Natl. Acad. Sci. U.S.A. 104 (47): 18866–18870. Bibcode:2007PNAS..10418866C. doi:10.1073/pnas.0702737104. PMC 2141868. PMID 17962418.     {{cite journal}}: |access-date= requires |url= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  10. ^ Template:PDFlink
  11. ^ a b c Kiehl, J.T. (1997). "Earth's annual global mean energy budget" (PDF). Bulletin of the American Meteorological Society. 78 (2): 197–208. Bibcode:1997BAMS...78..197K. doi:10.1175/1520-0477(1997)078<0197:EAGMEB>2.0.CO;2. ISSN 1520-0477. Archived from the original (PDF) on 30 March 2006. Retrieved 1 May 2006. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  12. ^ a b c "Water vapour: feedback or forcing?". RealClimate. 6 April 2005. Retrieved 1 May 2006.
  13. ^ a b IPCC Fourth Assessment Report, Table 2.14, Chap. 2, p. 212
  14. ^ Shindell, Drew T. (2005). "An emissions-based view of climate forcing by methane and tropospheric ozone". Geophysical Research Letters. 32 (4): L04803. Bibcode:2005GeoRL..3204803S. doi:10.1029/2004GL021900.
  15. ^ "Methane's Impacts on Climate Change May Be Twice Previous Estimates". Nasa.gov. 30 November 2007. Retrieved 16 October 2010.
  16. ^ Prather, Michael J. (2008). "NF3, the greenhouse gas missing from Kyoto". Geophysical Research Letters. 35 (12): L12810. Bibcode:2008GeoRL..3512810P. doi:10.1029/2008GL034542. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  17. ^ Isaksen, Ivar S. A. (20 April 2011). "Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions" (PDF). Global Biogeochemical Cycles. 25 (2). Bibcode:2011GBioC..25B2002I. doi:10.1029/2010GB003845. Retrieved 29 July 2011. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  18. ^ "AGU Water Vapor in the Climate System". Eso.org. 27 April 1995. Retrieved 11 September 2011.
  19. ^ Betts (2001). "6.3 Well-mixed Greenhouse Gases". Chapter 6 Radiative Forcing of Climate Change. Working Group I: The Scientific Basis IPCC Third Assessment Report - Climate Change 2001. UNEP/GRID-Arendal - Publications. Retrieved 16 October 2010. {{cite book}}: Invalid |display-authors=1 (help)
  20. ^ a b Jacob, Daniel (1999). Introduction to atmospheric chemistry. Princeton University Press. pp. 25–26. ISBN 0-691-00185-5.
  21. ^ "How long will global warming last?". RealClimate. Retrieved 12 June 2012.
  22. ^ Template:Cite article
  23. ^ Template:Cite article
  24. ^ Meehl, G.A. (2007). "Frequently Asked Question 10.3: If emissions of greenhouse gases are reduced, how quickly do their concentrations in the atmosphere decrease?". In S. Solomon, et al., (eds.) (ed.). Chapter 10: Global Climate Projections. 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 (CUP), Cambridge, United Kingdom and New York, NY, USA.: Print version:CUP. This version: IPCC website. Retrieved 1 June 2011. {{cite book}}: |editor= has generic name (help); Invalid |display-authors=1 (help)CS1 maint: multiple names: editors list (link)
  25. ^ See also: Archer, David (2005). "Fate of fossil fuel CO
    2     in geologic time"     (PDF). Journal of Geophysical Research. 110 (C9): C09S05.1–C09S05.6. Bibcode:2005JGRC..11009S05A. doi:10.1029/2004JC002625. Retrieved 27 July 2007.
  26. ^ See also: Caldeira, Ken; Wickett, Michael E. (2005). "Ocean model predictions of chemistry changes from carbon dioxide emissions to the atmosphere and ocean" (PDF). Journal of Geophysical Research. 110 (C9): C09S04.1–12. Bibcode:2005JGRC..11009S04C. doi:10.1029/2004JC002671. Archived from the original (PDF) on 10 August 2007. Retrieved 27 July 2007.
  27. ^ a b c d e f g h i Edited quote from public-domain source: US Environmental Protection Agency (EPA) (2010). "Climate Change Indicators in the United States". EPA. Greenhouse Gases: Figure 1. The Annual Greenhouse Gas Index, 1979-2008: Background.. This publication is also available as a PDF (page 18).
  28. ^ Use of ozone depleting substances in laboratories. TemaNord 2003:516
  29. ^ Montreal Protocol
  30. ^ "Chapter 1 Historical Overview of Climate Change Science - FAQ 1.3 Figure 1 description page 116" (PDF). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Intergovernmental Panel on Climate Change. 5 February 2007. Retrieved 25 April 2008.
  31. ^ "Chapter 3, IPCC Special Report on Emissions Scenarios, 2000". Intergovernmental Panel on Climate Change. 2000. Retrieved 16 October 2010.
  32. ^ "AR4 SYR SPM page 5" (PDF). Retrieved 16 October 2010.
  33. ^ "Climate Change 2001: The Scientific Basis". Intergovernmental Panel on Climate Change. Retrieved 16 October 2010.
  34. ^ Blasing, TJ (February 2011). "Recent Greenhouse Gas Concentrations". Carbon Dioxide Information Analysis Center. Retrieved 12 May 2011.
  35. ^ Image:Phanerozoic Carbon Dioxide.png
  36. ^ Berner, Robert A. (1994). "GEOCARB II: a revised model of atmospheric CO
    2     over Phanerozoic time"     (PDF). American Journal of Science. 294: 56–91. doi:10.2475/ajs.294.1.56. ISSN 0002-9599.
  37. ^ Royer, DL (2001). "Phanerozoic atmospheric CO
    2     change: evaluating geochemical and paleobiological approaches". Earth-Science Reviews. 54 (4): 349–92. Bibcode:2001ESRv...54..349R. doi:10.1016/S0012-8252(00)00042-8.     {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  38. ^ Berner, Robert A. (2001). "GEOCARB III: a revised model of atmospheric CO
    2     over Phanerozoic time"     (PDF). American Journal of Science. 301 (2): 182–204. doi:10.2475/ajs.301.2.182.     {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  39. ^ Beerling, DJ (2005). "Feedbacks and the co-evolution of plants and atmospheric CO
    2    "    . Proc. Natl. Acad. Sci. U.S.A. 102 (5): 1302–5. Bibcode:2005PNAS..102.1302B. doi:10.1073/pnas.0408724102. PMC 547859. PMID 15668402.     {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  40. ^ a b Hoffmann, PF (1998). "A neoproterozoic snowball earth". Science. 281 (5381): 1342–6. Bibcode:1998Sci...281.1342H. doi:10.1126/science.281.5381.1342. PMID 9721097. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  41. ^ Gerlach, TM (1991). "Present-day CO
    2     emissions from volcanoes". Transactions of the American Geophysical Union. 72 (23): 249–55. Bibcode:1991EOSTr..72..249.. doi:10.1029/90EO10192.
  42. ^ Flückiger, Jacqueline (2002). "High-resolution Holocene N2O ice core record and its relationship with CH4 and CO2". Global Biogeochemical Cycles. 16: 1010. Bibcode:2002GBioC..16a..10F. doi:10.1029/2001GB001417.
  43. ^ Friederike Wagner, Bent Aaby and Henk Visscher (2002). "Rapid atmospheric CO2 changes associated with the 8,200-years-B.P. cooling event". Proc. Natl. Acad. Sci. U.S.A. 99 (19): 12011–4. Bibcode:2002PNAS...9912011W. doi:10.1073/pnas.182420699. PMC 129389. PMID 12202744.
  44. ^ Andreas Indermühle, Bernhard Stauffer, Thomas F. Stocker (1999). "Early Holocene Atmospheric CO2 Concentrations". Science. 286 (5446): 1815. doi:10.1126/science.286.5446.1815a.{{cite journal}}: CS1 maint: multiple names: authors list (link) "Early Holocene atmospheric CO2 concentrations". Science. Retrieved 26 May 2005.
  45. ^ H.J. Smith, M Wahlen and D. Mastroianni (1997). "The CO2 concentration of air trapped in GISP2 ice from the Last Glacial Maximum-Holocene transition". Geophysical Research Letters. 24 (1): 1–4. Bibcode:1997GeoRL..24....1S. doi:10.1029/96GL03700.
  46. ^ "Monthly Average Carbon Dioxide Concentration, Mauna Loa Observatory" (PDF). Carbon Dioxide Information Analysis Center. 2005. Retrieved 14 December 2008.
  47. ^ Dr. Pieter Tans (3 May 2008) "Annual CO2 mole fraction increase (ppm)" for 1959–2007 National Oceanic and Atmospheric Administration Earth System Research Laboratory, Global Monitoring Division (additional details; see also K.A. Masarie, P.P. Tans (1995). "Extension and integration of atmospheric carbon dioxide data into a globally consistent measurement record". J. Geophys. Research. 100: 11593–610. Bibcode:1995JGR...10011593M. doi:10.1029/95JD00859.
  48. ^ Dumitru-Romulus Târziu, Victor-Dan Păcurar (2011). "Pădurea, climatul și energia". Rev. pădur. (in Template:Ro icon). 126 (1): 34–39. ISSN 1583-7890. 16720. Retrieved 11 June 2012. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: unrecognized language (link)(webpage has a translation button)
  49. ^ a b US Environmental Protection Agency (EPA) (2010). "Climate Change Indicators in the United States". EPA. Figure 1. The Annual Greenhouse Gas Index, 1979-2008.
  50. ^ US Environmental Protection Agency (EPA) (2010). "Climate Change Indicators in the United States". EPA. Figure 2. Global Greenhouse Gas Emissions by Sector, 1990-2005.
  51. ^ "Climate Change 2001: Working Group I: The Scientific Basis: figure 6-6". Retrieved 1 May 2006.
  52. ^ "The present carbon cycle - Climate Change". Grida.no. Retrieved 16 October 2010.
  53. ^ a b IPCC (2007). [PDF 7.83 MB "Chapter 7. Couplings Between Changes in the Climate System and Biogeochemistry"]. 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, United Kingdom and New York, NY, USA: Cambridge University Press. ISBN 978-0-521-88009-1. Retrieved 13 May 2008. {{cite book}}: Check |chapter-url= value (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  54. ^ IPCC (2007d). "6.1 Observed changes in climate and their effects, and their causes". 6 Robust findings, key uncertainties. Climate Change 2007: Synthesis Report. A Contribution of Working Groups I, II, and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Geneva, Switzerland: IPCC.
  55. ^ a b IPCC (2007d). "6.2 Drivers and projections of future climate changes and their impacts". 6 Robust findings, key uncertainties. Climate Change 2007: Synthesis Report. A Contribution of Working Groups I, II, and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Geneva, Switzerland: IPCC.
  56. ^ a b IPCC (2007d). "3.3.1 Impacts on systems and sectors". 3 Climate change and its impacts in the near and long term under different scenarios. Climate Change 2007: Synthesis Report. A Contribution of Working Groups I, II, and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Geneva, Switzerland: IPCC.
  57. ^ H. Steinfeld, P. Gerber, T. Wassenaar, V. Castel, M. Rosales, C. de Haan (2006) Livestock’s long shadow. Environmental issues and options. FAO Livestock, Environment and Development (LEAD) Initiative.
  58. ^ a b Raupach, M.R.; et al. (2007). "Global and regional drivers of accelerating CO2 emissions" (PDF). Proc. Natl. Acad. Sci. U.S.A. 104 (24): 10288–93. Bibcode:2007PNAS..10410288R. doi:10.1073/pnas.0700609104. PMC 1876160. PMID 17519334.
  59. ^ a b c Grubb, M. (July–September 2003). "The economics of the Kyoto protocol" (PDF). World Economics. 4 (3).
  60. ^ Lerner & K. Lee Lerner, Brenda Wilmoth (2006). "Environmental issues: essential primary sources". Thomson Gale. Retrieved 11 September 2006.
  61. ^ a b "Kyoto Protocol". United Nations Framework Convention on Climate Change. Home > Kyoto Protocol.
  62. ^ a b King, D.; et al. (July 2011), "Copenhagen and Cancun", International climate change negotiations: Key lessons and next steps, Oxford, UK: Smith School of Enterprise and the Environment, University of Oxford, p. 12, doi:10.4210/ssee.pbs.2011.0003 {{citation}}: Explicit use of et al. in: |author= (help) PDF version is also available
  63. ^ Evans, Kimberly Masters (2005). "The greenhouse effect and climate change". The environment: a revolution in attitudes. Detroit: Thomson Gale. ISBN 0-7876-9082-1.
  64. ^ "INVENTORY OF U.S. GREENHOUSE GAS EMISSIONS AND SINKS: 1990–2010" (PDF). U.S. Environmental Protection Agency. 15 April 2012. p. 1.4. Retrieved 2 June 2012.
  65. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1146/annurev.energy.25.1.441, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1146/annurev.energy.25.1.441 instead.
  66. ^ Includes the Kyoto "basket" of GHGs
  67. ^ Rogner, H.-H., D. Zhou, R. Bradley. P. Crabbé, O. Edenhofer, B.Hare, L. Kuijpers, M. Yamaguchi (2007). "1.3.1 Review of the last three decades". In B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (ed.). Introduction. Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. ISBN 978-0-521-88011-4.{{cite book}}: CS1 maint: multiple names: authors list (link) This citation clarifies the time period (1970-2004) for the observed emissions trends
  68. ^ UNEP (November 2011), Bridging the Emissions Gap: A UNEP Synthesis Report (PDF), Nairobi, Kenya: United Nations Environment Programme (UNEP), ISBN 978-92-807-3229-0 UNEP Stock Number: DEW/1470/NA
  69. ^ a b World Bank (2010). "Selected Development Indicators" (PDF). World Development Report 2010: Development and Climate Change (PDF). Washington DC, USA: The International Bank for Reconstruction and Development / The World Bank. Tables A1 and A2. doi:10.1596/978-0-8213-7987-5. ISBN 9780821379875.
  70. ^ a b Bader, N. and Bleichwitz, R. (2009). "Measuring urban greenhouse gas emissions: The challenge of comparability. ''S.A.P.I.EN.S.'' '''2''' (3)". Sapiens.revues.org. Retrieved 11 September 2011.{{cite web}}: CS1 maint: multiple names: authors list (link)
  71. ^ a b c d e f g h Banuri, T. (1996). Equity and social considerations. In: Climate change 1995: Economic and social dimensions of climate change. Contribution of Working Group III to the Second Assessment Report of the Intergovernmental Panel on Climate Change (J.P. Bruce et al. Eds.) (PDF). This version: Printed by Cambridge University Press, Cambridge, UK, and New York, NY, USA. PDF version: IPCC website. doi:10.2277/0521568544. ISBN 978-0-521-56854-8. {{cite book}}: Invalid |display-authors=1 (help)
  72. ^ IEA (2007). World energy outlook 2007 edition – China and India insights. International Energy Agency (IEA), Head of Communication and Information Office, 9 rue de la Fédération, 75739 Paris Cedex 15, France. p. 600. ISBN 978-92-64-02730-5. Retrieved 4 May 2010.
  73. ^ Holtz-Eakin, D. (1995). "Stoking the fires? CO2 emissions and economic growth". Journal of Public Economics. 57 (1): 85–101. doi:10.1016/0047-2727(94)01449-X. Retrieved 20 April 2011.
  74. ^ Herzog, T. (November 2006). Yamashita, M.B. (ed.). Target: intensity - an analysis of greenhouse gas intensity targets (PDF). World Resources Institute. ISBN 1-56973-638-3. Retrieved 11 April 2011. {{cite book}}: Invalid |display-authors=1 (help)
  75. ^ IPCC (2007). "Annex I: Glossary J-P". In B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (ed.). Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Print version: Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. This version: IPCC website. ISBN 978-0-521-88011-4. Retrieved 11 April 2011.{{cite book}}: CS1 maint: multiple names: editors list (link)
  76. ^ Markandya, A. (2001). "7.3.5 Cost Implications of Alternative GHG Emission Reduction Options and Carbon Sinks". In B. Metz; et al. (eds.). Costing Methodologies. Climate Change 2001: Mitigation. Contribution of Working Group III to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Print version: Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. This version: GRID-Arendal website. doi:10.2277/0521015022. ISBN 978-0-521-01502-8. Retrieved 11 April 2011. {{cite book}}: Explicit use of et al. in: |editor= (help); Invalid |display-authors=1 (help)
  77. ^ Botzen, W.J.W.; et al. (2008). "Cumulative CO
    2     emissions: shifting international responsibilities for climate debt"     (PDF). Climate Policy. 8. Earthscan: 570. doi:10.3763/cpol.2008.0539. ISSN (print), 1752-7457 (online) 1469-3062 (print), 1752-7457 (online).     {{cite journal}}: Check |issn= value (help); Explicit use of et al. in: |author= (help)
  78. ^ a b c Höhne, N.; et al. (24 September 2010). "Contributions of individual countries' emissions to climate change and their uncertainty" (PDF). Climatic Change. Springer Science+Business Media B.V. doi:10.1007/s10584-010-9930-6. {{cite journal}}: Explicit use of et al. in: |author= (help)
  79. ^ a b c International Energy Agency (IEA) (2009), World Energy Outlook 2009 (PDF), Paris, France: IEA, pp. 179–180, ISBN 978-92-64-06130-9
  80. ^ Rogner, H.-H., D. Zhou, R. Bradley. P. Crabbé, O. Edenhofer, B.Hare, L. Kuijpers, M. Yamaguchi (2007), "1.3.1 Review of the last three decades", in B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (ed.), Introduction, Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, ISBN 978-0-521-88011-4{{citation}}: CS1 maint: multiple names: authors list (link)
  81. ^ The cited paper uses the term "start date" instead of "base year."
  82. ^ a b c PBL (25 June 2009). "Global CO2 emissions: annual increase halves in 2008". Netherlands Environmental Assessment Agency (PBL) website. Retrieved 5 May 2010.
  83. ^ Carbon Trust (March 2009). "Global Carbon Mechanisms: Emerging lessons and implications (CTC748)". Carbon Trust website. p. 24. Retrieved 31 March 2010.
  84. ^ International Energy Agency (IEA) (2011), CO
    2     Emissions From Fuel Combustion: Highlights (2011 edition)    , Paris, France: IEA, p. 9
  85. ^ International Energy Agency (IEA) (2011), CO
    2     Emissions From Fuel Combustion: Highlights (2011 edition): Excel spreadsheet     (XLS), Paris, France: IEA
  86. ^ World Resources Institute (WRI) (2011), Climate Analysis Indicators Tool (CAIT): Indicators: GHG Emissions: Cumulative Emissions (free registration required), Washington DC, USA: WRI
  87. ^ Helm, D.; et al. (10 December 2007). Too Good To Be True? The UK's Climate Change Record (PDF). Website of Dieter Helm, a professor at the University of Oxford and a Fellow of New College, Oxford. p. 3. {{cite book}}: Explicit use of et al. in: |author= (help)
  88. ^ a b c Davis, S.K. and K. Caldeira (8 March 2010). "Consumption-based Accounting of CO2 Emissions" (PDF). Proceedings of the National Academy of Sciences Early Edition. 107 (12). Bibcode:2010PNAS..107.5687D. doi:10.1073/pnas.0906974107. Retrieved 18 April 2011.
  89. ^ e.g., Gupta et al. (2007) assessed the scientific literature on climate change mitigation policy: Gupta, S.; et al. (2007). Chapter 13: Policies, instruments, and co-operative arrangements. In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)). Cambridge University Press. ISBN 9780521880114. {{cite book}}: Explicit use of et al. in: |author= (help)
  90. ^ International Energy Agency (IEA) (2012). "International Energy Agency - Energy Policy". Paris, France: IEA.
  91. ^ Organization for Economic Co-operation and Development (OECD) / International Energy Agency (IEA) (2012). "IEA Publications Bookshop: IEA Publications on 'Energy Policy'". Paris, France: OECD/IEA.
  92. ^ United Nations Environment Programme (UNEP) (November 2011), Bridging the Emissions Gap: A UNEP Synthesis Report (PDF), Nairobi, Kenya: UNEP, ISBN 978-92-807-3229-0 UNEP Stock Number: DEW/1470/NA
  93. ^ World Bank (2010). "4. Energizing development without compromising the climate" (PDF). World Development Report 2010: Development and Climate Change (PDF). Washington DC, USA: The International Bank for Reconstruction and Development / The World Bank. p. 192. doi:10.1596/978-0-8213-7987-5. ISBN 9780821379875. {{cite book}}: More than one of |at= and |page= specified (help)
  94. ^ United Nations Framework Convention on Climate Change (UNFCCC) (2005). Sixth compilation and synthesis of initial national communications from Parties not included in Annex I to the Convention. Note by the secretariat. Executive summary (PDF). Geneva, Switzerland: United Nations Office. pp. 10–12.
  95. ^ a b c d United Nations Framework Convention on Climate Change (UNFCCC) (2011). Compilation and synthesis of fifth national communications. Executive summary. Note by the secretariat (PDF). Geneva (Switzerland): United Nations Office at Geneva. pp. 9–10.
  96. ^ Fisher, B.; et al. (2007). "3.1 Emissions scenarios". In B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (ed.). Chapter 3: Issues related to mitigation in the long-term context. Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. ISBN 978-0-521-88011-4. {{cite book}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: editors list (link)
  97. ^ Rogner, H.-H., D. Zhou, R. Bradley. P. Crabbé, O. Edenhofer, B.Hare, L. Kuijpers, M. Yamaguchi (2007). "1.3.2 Future outlook". In B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (ed.). Introduction. Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. ISBN 978-0-521-88011-4.{{cite book}}: CS1 maint: multiple names: authors list (link)
  98. ^ Rogner, H.-H., D. Zhou, R. Bradley. P. Crabbé, O. Edenhofer, B.Hare, L. Kuijpers, M. Yamaguchi (2007). "1.3.2.4 Total GHG emissions". In B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (ed.). Introduction. Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. ISBN 978-0-521-88011-4.{{cite book}}: CS1 maint: multiple names: authors list (link)
  99. ^ carbon dioxide, methane, nitrous oxide, sulphur hexafluoride
  100. ^ "Greenhouse Gas Emissions from a Typical Passenger Vehicle, US Environment Protection Agency" (PDF). Epa.gov. Retrieved 11 September 2011.
  101. ^ Engber, Daniel (1 November 2006). "How gasoline becomes CO2, Slate Magazine". Slate.com. Retrieved 11 September 2011.
  102. ^ "Volume calculation for carbon dioxide". Icbe.com. Retrieved 11 September 2011.
  103. ^ "Voluntary Reporting of Greenhouse Gases Program". Energy Information Administration. Retrieved 21 August 2009.
  104. ^ Obersteiner M; Azar C; Kauppi P; et al. (October 2001). "Managing climate risk". Science. 294 (5543): 786–7. doi:10.1126/science.294.5543.786b. PMID 11681318. {{cite journal}}: Unknown parameter |author-separator= ignored (help)
  105. ^ Azar, C., Lindgren, K., Larson, E.D. and Möllersten, K. (2006). "Carbon capture and storage from fossil fuels and biomass – Costs and potential role in stabilising the atmosphere" (PDF). Climatic Change. 74: 47–79. doi:10.1007/s10584-005-3484-7.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  106. ^ a b c "Geoengineering the climate: science, governance and uncertainty". The Royal Society. 2009. Retrieved 12 September 2009. [dead link]
  107. ^ Fischer, B.S., N. Nakicenovic, K. Alfsen, J. Corfee Morlot, F. de la Chesnaye, J.-Ch. Hourcade, K. Jiang, M. Kainuma, E. La Rovere, A. Matysek, A. Rana, K. Riahi, R. Richels, S. Rose, D. van Vuuren, R. Warren, (2007)“Issues related to mitigation in the long term context”, In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Inter-governmental Panel on Climate Change [B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds)], Cambridge University Press, Cambridge.
  108. ^ "Global Warming Opposing Viewpoints Paper". OPPapers. Retrieved 12 September 2011.

VAN DIJK, P., ZHANG, J., JUN, W., KUENZER, C. and K.H. WOLF, 2011: Assessment of the contribution of in-situ combustion of coal to greenhouse gas emission; based on a comparison of Chinese mining information to previous remote sensing estimates. International Journal of Coal Geology, Special Issue RS/GIS, DOI: 10.1016/j.coal.2011.01.009; pp. 108–119

Wikisource has original text related to this article:
Carbon dioxide emissions
Methane emissions

Retrieved from "https://en.wikipedia.org/w/index.php?title=Greenhouse_gas&oldid=514858344"