Greenhouse gas

For other uses, see GHG.

refer to caption and image description
Greenhouse effect schematic showing energy flows between space, the atmosphere, and Earth's surface. Energy influx and emittance are expressed in watts per square meter (W/m2).

A greenhouse gas (sometimes abbreviated GHG) 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 Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Without greenhouse gases, the average temperature of Earth's surface would be about −18 °C (0 °F),[2] rather than present average of 15 °C (59 °F).[3][4][5] In the Solar System, the atmospheres of Venus, Mars and Titan also contain gases that cause a greenhouse effect.

Human activities since the beginning of the Industrial Revolution (taken as the year 1750) have produced a 40% increase in the atmospheric concentration of carbon dioxide, from 280 ppm in 1750 to 400 ppm in 2015.[6][7] This increase has occurred despite the uptake of a large portion of the emissions by various natural "sinks" involved in the carbon cycle.[8][9] Anthropogenic carbon dioxide (CO2) emissions (i.e. emissions produced by human activities) come from combustion of carbon-based fuels, principally coal, oil, and natural gas, along with deforestation, soil erosion and animal agriculture.[10]

It has been estimated that if greenhouse gas emissions continue at the present rate, Earth's surface temperature could exceed historical values as early as 2047, with potentially harmful effects on ecosystems, biodiversity and the livelihoods of people worldwide.[11]

Gases in Earth's atmosphere

Greenhouse gases

refer to caption and adjacent text
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 absorb and emit infrared radiation in the wavelength range emitted by Earth.[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).[12] The proportion of an emission remaining in the atmosphere after a specified time is the "airborne fraction" (AF). More precisely, the annual airborne fraction is the ratio of the atmospheric increase in a given year to that year's total emissions. Over the last 50 years (1956–2006) the airborne fraction for CO2 has been increasing at 0.25 ± 0.21%/year.[13]

Non-greenhouse gases

The major atmospheric constituents, nitrogen (N
2
), oxygen (O
2
), and argon (Ar), are not greenhouse gases. This is because molecules containing two atoms of the same element such as N
2
and O
2
and monatomic molecules such as argon (Ar) have no net change in the distribution of their electrical charges when they vibrate and hence are almost totally unaffected by infrared radiation. Although molecules containing two atoms of different elements such as carbon monoxide (CO) or hydrogen chloride (HCl) absorb infrared radiation, these molecules are short-lived in the atmosphere owing to their reactivity and solubility. Therefore, they do not contribute significantly to the greenhouse effect and usually are omitted when discussing greenhouse gases.

Indirect radiative effects

world map of carbon monoxide concentrations in the lower atmosphere
The false colors in this image represent concentrations of carbon monoxide in the lower atmosphere, ranging from about 390 parts per billion (dark brown pixels), to 220 parts per billion (red pixels), to 50 parts per billion (blue pixels).[14]

Some gases have indirect radiative effects (whether or not they are greenhouse gases themselves). This happens in two main ways. One way is that when they break down in the atmosphere they produce another greenhouse gas. For example, methane and carbon monoxide (CO) are oxidized to give carbon dioxide (and methane oxidation also produces water vapor; that will be considered below). Oxidation of CO to CO2 directly produces an unambiguous increase in radiative forcing although the reason is subtle. The peak of the thermal IR emission from Earth's surface is very close to a strong vibrational absorption band of CO2 (667 cm−1). On the other hand, the single CO vibrational band only absorbs IR at much higher frequencies (2145 cm−1), where the ~300 K thermal emission of the surface is at least a factor of ten lower. On the other hand, oxidation of methane to CO2, which requires reactions with the OH radical, produces an instantaneous reduction, since CO2 is a weaker greenhouse gas than methane; but it has a longer lifetime. As described below this is not the whole story, since the oxidations of CO and CH
4
are intertwined by both consuming OH radicals. In any case, the calculation of the total radiative effect needs to include both the direct and indirect forcing.

A second type of indirect effect happens when chemical reactions in the atmosphere involving these gases change the concentrations of greenhouse gases. For example, the destruction of non-methane volatile organic compounds (NMVOCs) in the atmosphere can produce ozone. The size of the indirect effect can depend strongly on where and when the gas is emitted.[15]

Methane has a number of indirect effects in addition to forming CO2. Firstly, the main chemical that destroys methane in the atmosphere is the hydroxyl radical (OH). Methane reacts with OH and so more methane means that the concentration of OH goes down. Effectively, methane increases its own atmospheric lifetime and therefore its overall radiative effect. The second effect is that the oxidation of methane can produce ozone. Thirdly, as well as making CO2 the oxidation of methane produces water; this is a major source of water vapor in the stratosphere, which is otherwise very dry. CO and NMVOC also produce CO2 when they are oxidized. They remove OH from the atmosphere and this leads to higher concentrations of methane. The surprising effect of this is that the global warming potential of CO is three times that of CO2.[16] The same process that converts NMVOC to carbon dioxide can also lead to the formation of tropospheric ozone. Halocarbons have an indirect effect because they destroy stratospheric ozone. Finally hydrogen can lead to ozone production and CH
4
increases as well as producing water vapor in the stratosphere.[15]

Contribution of clouds to Earth's greenhouse effect

The major non-gas contributor to 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.[17][18]

Impacts on the overall greenhouse effect

refer to caption and adjacent text
Schmidt et al. (2010)[19] analysed how individual components of the atmosphere contribute to the total greenhouse effect. They estimated that water vapor accounts for about 50% of Earth's greenhouse effect, with clouds contributing 25%, carbon dioxide 20%, and the minor greenhouse gases and aerosols accounting for the remaining 5%. In the study, the reference model atmosphere is for 1980 conditions. Image credit: NASA.[20]

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, the direct radiative effect of a mass of methane is about 72 times stronger than the same mass of carbon dioxide over a 20-year time frame[21] but it is present in much smaller concentrations so that its total direct radiative effect is smaller, in part due to its 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)[22] argue that the contribution to climate change from methane is at least double previous estimates as a result of this effect.[23]

When ranked by their direct contribution to the greenhouse effect, the most important are:[17]

Compound
 
Formula
 
Concentration in
atmosphere[24] (ppm)
Contribution
(%)
Water vapor and clouds H
2
O
10–50,000(A) 36–72%  
Carbon dioxide CO2 ~400 9–26%
Methane CH
4
~1.8 4–9%  
Ozone O
3
2–8(B) 3–7%  
notes:

(A) Water vapor strongly varies locally[25]
(B) The concentration in stratosphere. About 90% of the ozone in Earth's atmosphere is contained in the stratosphere.

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.[26]

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.[17][18] In addition, some gases such as methane are known to have large indirect effects that are still being quantified.[27]

Atmospheric lifetime

Aside from water vapor, which has a residence time of about nine days,[28] major greenhouse gases are well mixed and take many years to leave the atmosphere.[29] 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)[30] defines the lifetime \tau of an atmospheric species X in a one-box model as the average time that a molecule of X remains in the box. Mathematically \tau can be defined as the ratio of the mass m (in kg) of X in the box to its removal rate, which is the sum of the flow of X out of the box (F_{out}), chemical loss of X (L), and deposition of X (D) (all in kg/s): \tau = \frac{m}{F_{out}+L+D}.[30] If one stopped pouring any of this gas into the box, then after a time \tau, 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.[31] The atmospheric lifetime of CO2 is estimated of the order of 30–95 years.[32] This figure accounts for CO2 molecules being removed from the atmosphere by mixing into the ocean, photosynthesis, and other processes. However, this excludes the balancing fluxes of CO2 into the atmosphere from the geological reservoirs, which have slower characteristic rates.[33] Although more than half of the CO2 emitted is removed from the atmosphere within a century, some fraction (about 20%) of emitted CO2 remains in the atmosphere for many thousands of years.[34] [35] [36] Similar issues apply to other greenhouse gases, many of which have longer mean lifetimes than CO2. E.g., N2O has a mean atmospheric lifetime of 114 years.[21]

Radiative forcing

Earth absorbs some of the radiant energy received from the sun, reflects some of it as light and reflects or radiates the rest back to space as heat.[37] Earth's surface temperature depends on this balance between incoming and outgoing energy.[37] If this energy balance is shifted, Earth's surface could become warmer or cooler, leading to a variety of changes in global climate.[37]

A number of natural and man-made mechanisms can affect the global energy balance and force changes in Earth's climate.[37] Greenhouse gases are one such mechanism.[37] Greenhouse gases in the atmosphere absorb and re-emit some of the outgoing energy radiated from Earth's surface, causing that heat to be retained in the lower atmosphere.[37] As explained above, some greenhouse gases remain in the atmosphere for decades or even centuries, and therefore can affect Earth's energy balance over a long time period.[37] Factors that influence Earth's energy balance can be quantified in terms of "radiative climate forcing."[37] Positive radiative forcing indicates warming (for example, by increasing incoming energy or decreasing the amount of energy that escapes to space), whereas negative forcing is associated with cooling.[37]

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 CO2 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. 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.[21] A 2014 analysis, however, states that although methane's initial impact is about 100 times greater than that of CO2, because of the shorter atmospheric lifetime, after six or seven decades, the impact of the two gases is about equal, and from then on methane's relative role continues to decline.[38] 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:[21]

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 30–95 1 1 1
Methane CH
4
12 72 25 7.6
Nitrous oxide N
2
O
114 289 298 153
CFC-12 CCl
2
F
2
100 11 000 10 900 5 200
HCFC-22 CHClF
2
12 5 160 1 810 549
Tetrafluoromethane CF
4
50 000 5 210 7 390 11 200
Hexafluoroethane C
2
F
6
10 000 8 630 12 200 18 200
Sulfur hexafluoride SF
6
3 200 16 300 22 800 32 600
Nitrogen trifluoride NF
3
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.[39] The phasing-out of less active HCFC-compounds will be completed in 2030.[40]

Carbon dioxide in Earth's atmosphere if half of global-warming emissions[41][42] are not absorbed.
(NASA simulation; 9 November 2015)
Nitrogen dioxide 2014 – global air quality levels
(released 14 December 2015).[43]

Natural and anthropogenic sources

refer to caption and article text
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.
refer to caption and image description
This diagram shows a simplified representation of the contemporary global carbon cycle. Changes are measured in gigatons of carbon per year (GtC/y). Canadell et al. (2007) estimated the growth rate of global average atmospheric CO2 for 2000–2006 as 1.93 parts-per-million per year (4.1 petagrams of carbon per year).[44]

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.[45][46]

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".[47] In AR4, "most of" is defined as more than 50%.

Abbreviations used in the two tables below: ppm = parts-per-million; ppb = parts-per-billion; ppt = parts-per-trillion; W/m2 = watts per square metre

Current greenhouse gas concentrations[6]
Gas Pre-1750
tropospheric
concentration[48]
Recent
tropospheric
concentration[49]
Absolute increase
since 1750
Percentage
increase
since 1750
Increased
radiative forcing
(W/m2)[50]
Carbon dioxide (CO2) 280 ppm[51] 395.4 ppm[52] 115.4 ppm 41.2% 1.88
Methane (CH
4
)
700 ppb[53] 1893 ppb /[54]
1762 ppb[54]
1193 ppb /
1062 ppb
170.4% /
151.7%
0.49
Nitrous oxide (N
2
O
)
270 ppb[50][55] 326 ppb /[54]
324 ppb[54]
56 ppb /
54 ppb
20.7% /
20.0%
0.17
Tropospheric
ozone (O
3
)
237 ppb[48] 337 ppb[48] 100 ppb 42% 0.4[56]
Relevant to radiative forcing and/or ozone depletion; all of the following have no natural sources and hence zero amounts pre-industrial[6]
Gas Recent
tropospheric
concentration
Increased
radiative forcing
(W/m2)
CFC-11
(trichlorofluoromethane)
(CCl
3
F
)
236 ppt /
234 ppt
0.061
CFC-12 (CCl
2
F
2
)
527 ppt /
527 ppt
0.169
CFC-113 (Cl
2
FC-CClF
2
)
74 ppt /
74 ppt
0.022
HCFC-22 (CHClF
2
)
231 ppt /
210 ppt
0.046
HCFC-141b (CH
3
CCl
2
F
)
24 ppt /
21 ppt
0.0036
HCFC-142b (CH
3
CClF
2
)
23 ppt /
21 ppt
0.0042
Halon 1211 (CBrClF
2
)
4.1 ppt /
4.0 ppt
0.0012
Halon 1301 (CBrClF
3
)
3.3 ppt /
3.3 ppt
0.001
HFC-134a (CH
2
FCF
3
)
75 ppt /
64 ppt
0.0108
Carbon tetrachloride (CCl
4
)
85 ppt /
83 ppt
0.0143
Sulfur hexafluoride (SF
6
)
7.79 ppt /[57]
7.39 ppt[57]
0.0043
Other halocarbons Varies by
substance
collectively
0.02
Halocarbons in total 0.3574
refer to caption and article text
400,000 years of ice core data

Ice cores provide evidence for greenhouse gas concentration variations over the past 800,000 years (see the following section). Both CO2 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 CO2 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 CO2 levels were likely 10 times higher than now.[58] Indeed, higher CO2 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.[59][60][61] The spread of land plants is thought to have reduced CO2 concentrations during the late Devonian, and plant activities as both sources and sinks of CO2 have since been important in providing stabilising feedbacks.[62] 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 CO2 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.[63] 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.[63][64][65]

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.[66] 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,[67] though others have argued that these findings more likely reflect calibration or contamination problems rather than actual CO2 variability.[68][69] 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

Refer to caption
Recent year-to-year increase of atmospheric CO2.
Refer to caption
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.[70]

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.[71]

Today, the stock of carbon in the atmosphere increases by more than 3 million tonnes per annum (0.04%) compared with the existing stock. This increase is the result of human activities by burning fossil fuels, deforestation and forest degradation in tropical and boreal regions.[72]

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 2011. [73] The AGGI measures the levels of greenhouse gases in the atmosphere based on their ability to cause changes in Earth's climate.[73]
This bar graph shows global greenhouse gas emissions by sector from 1990 to 2005, measured in carbon dioxide equivalents.[74]
Modern global CO2 emissions from the burning of fossil fuels.

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.[75] Natural sources of carbon dioxide are more than 20 times greater than sources due to human activity,[76] 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.[77]

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.[78] Future warming is projected to have a range of impacts, including sea level rise,[79] increased frequencies and severities of some extreme weather events,[79] loss of biodiversity,[80] and regional changes in agricultural productivity.[80]

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 CO2 emissions.[77]
  • livestock enteric fermentation and manure management,[81] 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 (N
    2
    O
    ) concentrations.

The seven sources of CO2 from fossil fuel combustion are (with percentage contributions for 2000–2004):[82]

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[83]
 4 %

Carbon dioxide, methane, nitrous oxide (N
2
O
) and three groups of fluorinated gases (sulfur hexafluoride (SF
6
), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs)) are the major anthropogenic greenhouse gases,[84]:147[85] and are regulated under the Kyoto Protocol international treaty, which came into force in 2005.[86] Emissions limitations specified in the Kyoto Protocol expired in 2012.[86] The Cancún agreement, agreed in 2010, includes voluntary pledges made by 76 countries to control emissions.[87] At the time of the agreement, these 76 countries were collectively responsible for 85% of annual global emissions.[87]

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.

Sectors

Tourism

According to UNEP global tourism is closely linked to climate change. Tourism is a significant contributor to the increasing concentrations of greenhouse gases in the atmosphere. Tourism accounts for about 50% of traffic movements. Rapidly expanding air traffic contributes about 2.5% of the production of CO2. The number of international travelers is expected to increase from 594 million in 1996 to 1.6 billion by 2020, adding greatly to the problem unless steps are taken to reduce emissions.[88]

Road Haulage

The road haulage industry plays a part in production of CO2, contributing around 20% of the UK’s total carbon emissions a year, with only the energy industry having a larger impact at around 39%.[89] Average carbon emissions within the haulage industry are falling—in the thirty-year period from 1977–2007, the carbon emissions associated with a 200-mile journey fell by 21 percent; NOx emissions are also down 87 percent, whereas journey times have fallen by around a third.[90] Due to their size, HGVs often receive criticism regarding their CO2 emissions; however, rapid development in engine technology and fuel management is having a largely positive effect.

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.[18] 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 and depends largely on temperature, from less than 0.01% in extremely cold regions up to 3% by mass at in saturated air at about 32 °C.[91] (See Relative humidity#other important facts.)

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 CH
4
and CO2.[92] Thus, water vapor responds to and amplifies effects of the other greenhouse gases. The Clausius–Clapeyron relation establishes that more water vapor will be present per unit volume at elevated temperatures. 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 (assuming that the relative humidity remains approximately constant; modeling and observational studies find that this is indeed so). 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.[93]

Direct greenhouse gas emissions

Between the period 1970 to 2004, GHG emissions (measured in CO2-equivalent)[94] 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.[95][96] Total anthropogenic emissions at the end of 2009 were estimated at 49.5 gigatonnes CO2-equivalent.[97]:15 These emissions include CO2 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 primary source of CO2 emissions is the burning of coal, natural gas, and petroleum for electricity and heat.[98]

Regional and national attribution of emissions

This figure shows the relative fraction of anthropogenic greenhouse gases coming from each of eight categories of sources, as estimated by the Emission Database for Global Atmospheric Research version 3.2, fast track 2000 project [1]. These values are intended to provide a snapshot of global annual greenhouse gas emissions in the year 2000. The top panel shows the sum over all anthropogenic greenhouse gases, weighted by their global warming potential over the next 100 years. This consists of 72% carbon dioxide, 18% methane, 8% nitrous oxide and 1% other gases. Lower panels show the comparable information for each of these three primary greenhouse gases, with the same coloring of sectors as used in the top chart. Segments with less than 1% fraction are not labeled.

There are several different ways of measuring GHG emissions, for example, see World Bank (2010)[99]:362 for tables of national emissions data. Some variables that have been reported[100] 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 systems, and continuous 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).[101] 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.[100]

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).[102]

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).[103]

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).[84]: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.[99]:370 Per capita emissions may be based on historical or annual emissions (Banuri et al., 1996, pp. 106–107).[101]

Land-use change

Refer to caption.
Greenhouse gas emissions from agriculture, forestry and other land use, 1970–2010.

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.[104] 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).[101]

There are substantial uncertainties in the measurement of net carbon emissions.[105] Additionally, there is controversy over how carbon sinks should be allocated between different regions and over time (Banuri et al., 1996, p. 93).[101] For instance, concentrating on more recent changes in carbon sinks is likely to favour those regions that have deforested earlier, e.g., Europe.

Greenhouse gas intensity

Refer to caption.
Greenhouse gas intensity in the year 2000, including land-use change.
Refer to caption.
Carbon intensity of GDP (using PPP) for different regions, 1982–2011.
Refer to caption.
Carbon intensity of GDP (using MER) for different regions, 1982–2011.

Greenhouse gas intensity is a ratio between greenhouse gas emissions and another metric, e.g., gross domestic product (GDP) or energy use. The terms "carbon intensity" and "emissions intensity" are also sometimes used.[106] GHG intensities may be calculated using market exchange rates (MER) or purchasing power parity (PPP) (Banuri et al., 1996, p. 96).[101] Calculations based on MER show large differences in intensities between developed and developing countries, whereas calculations based on PPP show smaller differences.

Cumulative and historical emissions

Cumulative energy-related CO2 emissions between the years 1850–2005 grouped into low-income, middle-income, high-income, the EU-15, and the OECD countries.
Cumulative energy-related CO2 emissions between the years 1850–2005 for individual countries.
Map of cumulative per capita anthropogenic atmospheric CO2 emissions by country. Cumulative emissions include land use change, and are measured between the years 1950 and 2000.
Regional trends in annual CO2 emissions from fuel combustion between 1971 and 2009.
Regional trends in annual per capita CO2 emissions from fuel combustion between 1971 and 2009.

Cumulative anthropogenic (i.e., human-emitted) emissions of CO2 from fossil fuel use are a major cause of global warming,[107] and give some indication of which countries have contributed most to human-induced climate change.[108]: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).[101] 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)[101] 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).[101] 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 CO2 emissions between 1890–2007.[109]: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%.[109]:179–180

Changes since a particular base year

Between 1970–2004, global growth in annual CO2 emissions was driven by North America, Asia, and the Middle East.[110] 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.[82] In comparison, methane has not increased appreciably, and N
2
O
by 0.25% y−1.

Using different base years for measuring emissions has an effect on estimates of national contributions to global warming.[108]:17–18[111] 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.[108]: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 CO2 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.[84]: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).[112] Other countries with fast growing emissions are South Korea, Iran, and Australia (which apart from the oil rich Persian Gulf states, now has the highest percapita emission rate in the world). On the other hand, annual per capita emissions of the EU-15 and the USA are gradually decreasing over time.[112] Emissions in Russia and Ukraine have decreased fastest since 1990 due to economic restructuring in these countries.[113]

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%.[112]

The GHG footprint, or greenhouse gas footprint, refers to the amount of GHG that are emitted during the creation of products or services. It is more comprehensive than the commonly used carbon footprint, which measures only carbon dioxide, one of many greenhouse gases.

2015 was the first year to see both total global economic growth and a reduction of carbon emissions.[114]

Top emitter countries

The top 40 countries emitting all greenhouse gases, showing both that derived from all sources including land clearance and forestry and also the CO2 component excluding those sources. Per capita figures are included. Data taken from World Resources Institute, Washington. Note that Indonesia and Brazil show very much higher than on graphs simply showing fossil fuel use.

Annual

In 2009, the annual top ten emitting countries accounted for about two-thirds of the world's annual energy-related CO2 emissions.[115]

Top-10 annual energy-related CO2 emitters for the year 2009
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

The C-Story of Human Civilization by PIK
Top-10 cumulative energy-related CO2 emitters between 1850–2008
Country % of world
total
Metric tonnes
CO2 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.[116] 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.[109]:179[117]: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)[117]: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).[117]:5 Carbon Trust research revealed that approximately 25% of all CO2 emissions from human activities 'flow' (i.e. are imported or exported) from one country to another. Major developed economies were found to be typically net importers of embodied carbon emissions — with UK consumption emissions 34% higher than production emissions, and Germany (29%), Japan (19%) and the USA (13%) also significant net importers of embodied emissions.[118]

Effect of policy

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,[119] International Energy Agency,[120][121] and United Nations Environment Programme.[122] Policies implemented by governments have included[123][124][125] national and regional targets to reduce emissions, promoting energy efficiency, and support for renewable energy such as Solar energy as an effective use of renewable energy because solar uses energy from the sun and does not release pollutants into the air.

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.[125]:3 Analysis by the UNFCCC (2011)[125]:8 suggested that policies and measures undertaken by Annex I Parties may have produced emission savings of 1.5 thousand Tg CO2-eq in the year 2010, with most savings made in the energy sector. The projected emissions saving of 1.5 thousand Tg CO2-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 CO2-eq does not include emissions savings in seven of the Annex I Parties.[125]:8

Projections

A wide range of projections of future GHG emissions have been produced.[126] Rogner et al. (2007)[127] assessed the scientific literature on GHG projections. Rogner et al. (2007)[95] 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.[95] Projected annual energy-related CO2 emissions in 2030 were 40–110% higher than in 2000, with two-thirds of the increase originating in developing countries.[95] Projected annual per capita emissions in developed country regions remained substantially lower (2.8–5.1 tonnes CO2) than those in developed country regions (9.6–15.1 tonnes CO2).[128] Projections consistently showed increase in annual world GHG emissions (the "Kyoto" gases,[129] measured in CO2-equivalent) of 25–90% by 2030, compared to 2000.[95]

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)[130][131][132]

Mass of carbon dioxide emitted per quantity of energy for various fuels[133]
Fuel name CO2
emitted
(lbs/106 Btu)
CO2
emitted
(g/MJ)
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
Tar-sand Bitumen
Coal (anthracite) 227 97.59

Life-cycle greenhouse-gas emissions of energy sources

A literature review of numerous energy sources CO2 emissions by the IPCC in 2011, found that, the CO2 emission value that fell within the 50th percentile of all total life cycle emissions studies conducted was as follows.[134]

Lifecycle greenhouse gas emissions by electricity source.
Technology Description 50th percentile
(g CO2/kWhe)
Hydroelectric reservoir 4
Ocean Energy wave and tidal 8
Wind onshore 12
Nuclear various generation II reactor types 16
Biomass various 18
Solar thermal parabolic trough 22
Geothermal hot dry rock 45
Solar PV Polycrystalline silicon 46
Natural gas various combined cycle turbines without scrubbing 469
Coal various generator types without scrubbing 1001

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 CO2 and water vapor (CO2 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 CO2, 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

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[135][136][137] and carbon dioxide air capture,[137] or to the soil as in the case with biochar.[137] The IPCC has pointed out that many long-term climate scenario models require large scale manmade negative emissions to avoid serious climate change.[138]

History of scientific research

In the late 19th century scientists experimentally discovered that N
2
and O
2
do not absorb infrared radiation (called, at that time, "dark radiation"), while water (both as true vapor and condensed in the form of microscopic droplets suspended in clouds) and CO2 and other poly-atomic gaseous molecules do absorb infrared radiation. In the early 20th century researchers realized that greenhouse gases in the atmosphere made 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 cause a substantial rise in global temperatures and changes to other parts of the climate system,[139] with consequences for the environment and for human health.

See also

References

  1. 1 2 "IPCC AR4 SYR Appendix Glossary" (PDF). Retrieved 14 December 2008.
  2. "NASA GISS: Science Briefs: Greenhouse Gases: Refining the Role of Carbon Dioxide". www.giss.nasa.gov. Retrieved 2016-04-26.
  3. 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.
  4. Le Treut H.; Somerville R.; Cubasch U.; Ding Y.; Mauritzen C.; Mokssit A.; Peterson T.; 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.
  5. "NASA Science Mission Directorate article on the water cycle". Nasascience.nasa.gov. Retrieved 2010-10-16.
  6. 1 2 3 From non-copyrighted source: Blasing, T. J. (February 2013), Current Greenhouse Gas Concentrations, doi:10.3334/CDIAC/atg.032, on CDIAC 2013. Details on copyright status: Frequently Asked Global Change Questions, Q34: I would like to use a diagram, image, graph, table, or other materials from the CDIAC Web site. How can I obtain permission? Are there copyright restrictions?, retrieved 2012-09-26, on CDIAC 2013. "All of the reports, graphics, data, and other information on the CDIAC Web site are freely and publicly available without copyright restrictions. However as a professional courtesy, we ask that the original data source be acknowledged."
  7. The most recent preliminary estimate of global monthly mean CO2 concentration (as of May 2013) is 396.71 ppm: (Ed Dlugokencky and Pieter Tans, NOAA/ESRL ()
  8. "Frequently asked global change questions". Carbon Dioxide Information Analysis Center.
  9. ESRL Web Team (14 January 2008). "Trends in carbon dioxide". Esrl.noaa.gov. Retrieved 2011-09-11.
  10. "AR4 SYR Synthesis Report Summary for Policymakers – 2 Causes of change". ipcc.ch.
  11. Mora, C (2013). "The projected timing of climate departure from recent variability". Nature 502: 183–187. doi:10.1038/nature12540.
  12. "Chapter 7: Couplings Between Changes in the Climate System and Biogeochemistry" (PDF). IPCC WG1 AR4 Report. IPCC. 2007. p. FAQ 7.1; report page 512; pdf page 14. Retrieved 11 July 2011.
  13. Canadell, J. G.; Le Quere, C.; Raupach, M. R.; Field, C. B.; Buitenhuis, E. T.; Ciais, P.; Conway, T. J.; Gillett, N. P.; Houghton, R. A.; Marland, G. (2007). "Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks". Proc. Natl. Acad. Sci. U.S.A. 104 (47): 18866–70. Bibcode:2007PNAS..10418866C. doi:10.1073/pnas.0702737104. PMC 2141868. PMID 17962418. Retrieved 15 March 2008. Cite uses deprecated parameter |coauthors= (help)
  14. http://earthobservatory.nasa.gov/Library/RemoteSensingAtmosphere/remote_sensing6.html Archived 20 September 2008 at the Wayback Machine.
  15. 1 2 Forster, P.; et al. (2007). "2.10.3 Indirect GWPs". Changes in Atmospheric Constituents and in Radiative Forcing. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. Retrieved 2012-12-02.
  16. MacCarty, N. "Laboratory Comparison of the Global-Warming Potential of Six Categories of Biomass Cooking Stoves" (PDF). Approvecho Research Center.
  17. 1 2 3 Kiehl, J.T.; Kevin E. Trenberth (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. Archived from the original (PDF) on 30 March 2006. Retrieved 1 May 2006.
  18. 1 2 3 "Water vapour: feedback or forcing?". RealClimate. 6 April 2005. Retrieved 1 May 2006.
  19. Schmidt, G. A.; R. Ruedy; R. L. Miller; A. A. Lacis (2010), "The attribution of the present-day total greenhouse effect" (PDF), J. Geophys. Res. 115, Bibcode:2010JGRD..11520106S, doi:10.1029/2010JD014287, D20106. Web page for paper.
  20. Lacis, A. (October 2010), NASA GISS: CO2: The Thermostat that Controls Earth's Temperature, New York: NASA GISS
  21. 1 2 3 4 IPCC Fourth Assessment Report, Table 2.14, Chap. 2, p. 212
  22. 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.
  23. "Methane's Impacts on Climate Change May Be Twice Previous Estimates". Nasa.gov. 30 November 2007. Retrieved 2010-10-16.
  24. http://www3.epa.gov/climatechange/science/indicators/ghg/ghg-concentrations.html. Missing or empty |title= (help)
  25. Wallace, John M. and Peter V. Hobbs. Atmospheric Science; An Introductory Survey.Elsevier. Second Edition, 2006. ISBN 978-0-12-732951-2. Chapter 1
  26. Prather, Michael J.; J Hsu (2008). "NF
    3
    , the greenhouse gas missing from Kyoto". Geophysical Research Letters 35 (12): L12810. Bibcode:2008GeoRL..3512810P. doi:10.1029/2008GL034542.
  27. Isaksen, Ivar S. A.; Michael Gauss; Gunnar Myhre; Katey M. Walter Anthony; Carolyn Ruppel (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.
  28. "AGU Water Vapor in the Climate System". Eso.org. 27 April 1995. Retrieved 2011-09-11.
  29. 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 2010-10-16.
  30. 1 2 Jacob, Daniel (1999). Introduction to atmospheric chemistry. Princeton University Press. pp. 25–26. ISBN 0-691-00185-5.
  31. "How long will global warming last?". RealClimate. Retrieved 2012-06-12.
  32. Jacobson, MZ (2005). "Correction to "Control of fossil-fuel particulate black carbon and organic matter, possibly the most effective method of slowing global warming."". J. Geophys. Res. 110. pp. D14105. doi:10.1029/2005JD005888.
  33. Archer, David (2009). "Atmospheric lifetime of fossil fuel carbon dioxide". Annual Review of Earth and Planetary Sciences 37. pp. 117–134. doi:10.1146/annurev.earth.031208.100206.
  34. 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. 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, USA.: Print version:CUP. This version: IPCC website. Retrieved 2011-06-01.
  35. See also: Archer, David (2005). "Fate of fossil fuel CO2 in geologic time" (PDF). Journal of Geophysical Research 110 (C9): C09S05.1–6. Bibcode:2005JGRC..11009S05A. doi:10.1029/2004JC002625. Retrieved 27 July 2007.
  36. 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.
  37. 1 2 3 4 5 6 7 8 9 Edited quote from public-domain source: "Climate Change Indicators in the United States". U.S. Environmental Protection Agency (EPA). 2010. Greenhouse Gases: Figure 1. The Annual Greenhouse Gas Index, 1979–2008: Background.. This publication is also available as a PDF (page 18).
  38. David L. Chandler, How to count methane emissions, MIT News, April 25, 2014 (Accessed Jan. 15, 2015). Referenced paper is Jessika Trancik and Morgan Edwards, Climate impacts of energy technologies depend on emissions timing, Nature Climate Change, Volume 4, April 25, 2014, p. 347 (Accessed Jan. 15, 2015).
  39. Use of ozone depleting substances in laboratories. TemaNord 2003:516
  40. Montreal Protocol
  41. St. Fleur, Nicholas (10 November 2015). "Atmospheric Greenhouse Gas Levels Hit Record, Report Says". New York Times. Retrieved 11 November 2015.
  42. Ritter, Karl (9 November 2015). "UK: In 1st, global temps average could be 1 degree C higher". AP News. Retrieved 11 November 2015.
  43. Cole, Steve; Gray, Ellen (14 December 2015). "New NASA Satellite Maps Show Human Fingerprint on Global Air Quality". NASA. Retrieved 14 December 2015.
  44. Canadell, J. G.; et al. (20 November 2007), "Contributions to Accelerating Atmospheric CO2 Growth from Economic Activity, Carbon Intensity, and Efficiency of Natural Sinks (Results and Discussion: Growth in Atmospheric CO2)", Proceedings of the National Academy of Sciences of the United States of America 104 (47): 18866–18870, Bibcode:2007PNAS..10418866C, doi:10.1073/pnas.0702737104, PMC 2141868, PMID 17962418
  45. "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.
  46. "Chapter 3, IPCC Special Report on Emissions Scenarios, 2000". Intergovernmental Panel on Climate Change. 2000. Retrieved 2010-10-16.
  47. "AR4 SYR SPM page 5" (PDF). Retrieved 2010-10-16.
  48. 1 2 3 Ehhalt, D.; et al., "Ch 4. Atmospheric Chemistry and Greenhouse Gases", Table 4.1, in IPCC TAR WG1 2001, pp. 244–245. Referred to by: Blasing, T. J. (February 2013), Current Greenhouse Gas Concentrations, doi:10.3334/CDIAC/atg.032, on CDIAC 2013. Based on Blasing et al. (2013): Pre-1750 concentrations of CH4,N2O and current concentrations of O3, are taken from Table 4.1 (a) of the IPCC Intergovernmental Panel on Climate Change), 2001. Following the convention of IPCC (2001), inferred global-scale trace-gas concentrations from prior to 1750 are assumed to be practically uninfluenced by human activities such as increasingly specialized agriculture, land clearing, and combustion of fossil fuels. Preindustrial concentrations of industrially manufactured compounds are given as zero. The short atmospheric lifetime of ozone (hours-days) together with the spatial variability of its sources precludes a globally or vertically homogeneous distribution, so that a fractional unit such as parts per billion would not apply over a range of altitudes or geographical locations. Therefore a different unit is used to integrate the varying concentrations of ozone in the vertical dimension over a unit area, and the results can then be averaged globally. This unit is called a Dobson Unit (D.U.), after G. M. B. Dobson, one of the first investigators of atmospheric ozone. A Dobson unit is the amount of ozone in a column that, unmixed with the rest of the atmosphere, would be 10 micrometers thick at standard temperature and pressure.
  49. Because atmospheric concentrations of most gases tend to vary systematically over the course of a year, figures given represent averages over a 12-month period for all gases except ozone (O3), for which a current global value has been estimated (IPCC, 2001, Table 4.1a). CO2 averages for year 2012 are taken from the National Oceanic and Atmospheric Administration, Earth System Research Laboratory, web site: www.esrl.noaa.gov/gmd/ccgg/trends maintained by Dr. Pieter Tans. For other chemical species, the values given are averages for 2011. These data are found on the CDIAC AGAGE web site: http://cdiac.ornl.gov/ndps/alegage.html or the AGAGE home page: http://agage.eas.gatech.edu.
  50. 1 2 Forster, P.; et al., "Ch 2: Changes in Atmospheric Constituents and in Radiative Forcing", Table 2.1, in IPCC AR4 WG1 2007, p. 141. Referred to by: Blasing, T. J. (February 2013), Current Greenhouse Gas Concentrations, doi:10.3334/CDIAC/atg.032, on CDIAC 2013. For the latest updates, see the NOAA Annual Greenhouse Gas Index at: .
  51. Prentice, I. C.; et al., "Ch 3. The Carbon Cycle and Atmospheric Carbon Dioxide", Executive summary, in IPCC TAR WG1 2001, p. 185. Referred to by: Blasing, T. J. (February 2013), Current Greenhouse Gas Concentrations, doi:10.3334/CDIAC/atg.032, on CDIAC 2013
  52. Recent CO2 concentration (395.4 ppm) is the 2013 average taken from globally averaged marine surface data given by the National Oceanic and Atmospheric Administration Earth System Research Laboratory, website: http://www.esrl.noaa.gov/gmd/ccgg/trends/index.html#global. Please read the material on that web page and reference Dr. Pieter Tans when citing this average (Dr. Pieter Tans, NOAA/ESRL http://www.esrl.noaa.gov/gmd/ccgg/trends). The oft-cited Mauna Loa average for 2012 is 393.8 ppm, which is a good approximation although typically about 1 ppm higher than the spatial average given above. Refer to http://www.esrl.noaa.gov/gmd/ccgg/trends for records back to the late 1950s.
  53. ppb = parts-per-billion
  54. 1 2 3 4 The first value in a cell represents Mace Head, Ireland, a mid-latitude Northern-Hemisphere site, and the second value represents Cape Grim, Tasmania, a mid-latitude Southern-Hemisphere site. "Current" values given for these gases are annual arithmetic averages based on monthly background concentrations for year 2011. The SF
    6
    values are from the AGAGE gas chromatography – mass spectrometer (gc-ms) Medusa measuring system. Source: Advanced Global Atmospheric Gases Experiment (AGAGE) data posted on CDIAC web site at: http://cdiac.ornl.gov/ftp/ale_gage_Agage/. These data are compiled from data on finer time scales in the ALE/GAGE/AGAGE database (Prinn et al., 2000). These data represent the work of several investigators at various institutions; guidelines on citing the various parts of the AGAGE database are found within the ALE/GAGE/AGAGE database, see: .
  55. The pre-1750 value for N
    2
    O
    is consistent with ice-core records from 10,000 B.C.E. through 1750 C.E.: "Summary for policymakers", Figure SPM.1, IPCC, in IPCC AR4 WG1 2007, p. 3. Referred to by: Blasing, T. J. (February 2013), Current Greenhouse Gas Concentrations, doi:10.3334/CDIAC/atg.032, on CDIAC 2013
  56. Changes in stratospheric ozone have resulted in a decrease in radiative forcing of 0.05 W/m2: Forster, P.; et al., "Ch 2: Changes in Atmospheric Constituents and in Radiative Forcing", Table 2.12, in IPCC AR4 WG1 2007, p. 204. Referred to by: Blasing, T. J. (February 2013), Current Greenhouse Gas Concentrations, doi:10.3334/CDIAC/atg.032, on CDIAC 2013
  57. 1 2 For SF
    6
    data from January 2004 onward see: . For data from 1995 through 2004, see the National Oceanic and Atmospheric Administration (NOAA), Halogenated and other Atmospheric Trace Species (HATS) site at: . Concentrations of SF
    6
    from 1970 through 1999, obtained from Antarctic firn (consolidated deep snow) air samples, can be found in W. T. Sturges et al.
  58. File:Phanerozoic Carbon Dioxide.png
  59. Berner, Robert A. (January 1994). "GEOCARB II: a revised model of atmospheric CO2 over Phanerozoic time" (PDF). American Journal of Science 294 (1): 56–91. doi:10.2475/ajs.294.1.56.
  60. Royer, D. L.; R. A. Berner; D. J. Beerling (2001). "Phanerozoic atmospheric CO2 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.
  61. Berner, Robert A.; Kothavala, Zavareth (2001). "GEOCARB III: a revised model of atmospheric CO2 over Phanerozoic time" (PDF). American Journal of Science 301 (2): 182–204. doi:10.2475/ajs.301.2.182.
  62. Beerling, D. J.; Berner, R. A. (2005). "Feedbacks and the co-evolution of plants and atmospheric CO2". Proc. Natl. Acad. Sci. U.S.A. 102 (5): 1302–5. Bibcode:2005PNAS..102.1302B. doi:10.1073/pnas.0408724102. PMC 547859. PMID 15668402.
  63. 1 2 Hoffmann, PF; AJ Kaufman; GP Halverson; DP Schrag (1998). "A neoproterozoic snowball earth". Science 281 (5381): 1342–6. Bibcode:1998Sci...281.1342H. doi:10.1126/science.281.5381.1342. PMID 9721097.
  64. Gerlach, TM (1991). "Present-day CO2 emissions from volcanoes". Transactions of the American Geophysical Union 72 (23): 249–55. Bibcode:1991EOSTr..72..249.. doi:10.1029/90EO10192.
  65. See also: "U.S. Geological Survey". 14 June 2011. Retrieved 15 October 2012.
  66. Flückiger, Jacqueline (2002). "High-resolution Holocene N
    2
    O
    ice core record and its relationship with CH
    4
    and CO2". Global Biogeochemical Cycles 16: 1010. Bibcode:2002GBioC..16a..10F. doi:10.1029/2001GB001417.
  67. 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.
  68. Andreas Indermühle, Bernhard Stauffer, Thomas F. Stocker (1999). "Early Holocene Atmospheric CO2 Concentrations". Science 286 (5446): 1815. doi:10.1126/science.286.5446.1815a. "Early Holocene atmospheric CO2 concentrations". Science. Retrieved 26 May 2005.
  69. 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.
  70. "Monthly Average Carbon Dioxide Concentration, Mauna Loa Observatory" (PDF). Carbon Dioxide Information Analysis Center. 2005. Retrieved 14 December 2008.
  71. 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.
  72. Dumitru-Romulus Târziu, Victor-Dan Păcurar (Jan 2011). "Pădurea, climatul și energia". Rev. pădur. (in Romanian) 126 (1): 34–39. ISSN 1583-7890. 16720. Retrieved 2012-06-11.(webpage has a translation button)
  73. 1 2 "Climate Change Indicators in the United States". NOAA. 2012. Figure 4. The Annual Greenhouse Gas Index, 1979–2011.
  74. "Climate Change Indicators in the United States". U.S. Environmental Protection Agency (EPA). 2010. Figure 2. Global Greenhouse Gas Emissions by Sector, 1990–2005.
  75. "Climate Change 2001: Working Group I: The Scientific Basis: figure 6-6". Retrieved 1 May 2006.
  76. "The present carbon cycle — Climate Change". Grida.no. Retrieved 2010-10-16.
  77. 1 2 Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor and H. L. Miller, ed. (2007). "Chapter 7. Couplings Between Changes in the Climate System and Biogeochemistry" (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. Cambridge, United Kingdom and New York, USA: Cambridge University Press. ISBN 978-0-521-88009-1. Retrieved 13 May 2008.
  78. 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.
  79. 1 2 "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. 2007d.
  80. 1 2 "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. 2007d.
  81. 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.
  82. 1 2 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.
  83. Schrooten, L; De Vlieger, Ina; Int Panis, Luc; Styns, R. Torfs, K; Torfs, R (2008). "Inventory and forecasting of maritime emissions in the Belgian sea territory, an activity based emission model". Atmospheric Environment 42 (4): 667–676.
  84. 1 2 3 Grubb, M. (July–September 2003). "The economics of the Kyoto protocol" (PDF). World Economics 4 (3).
  85. Lerner & K. Lee Lerner, Brenda Wilmoth (2006). "Environmental issues: essential primary sources". Thomson Gale. Retrieved 11 September 2006.
  86. 1 2 "Kyoto Protocol". United Nations Framework Convention on Climate Change. Home > Kyoto Protocol.
  87. 1 2 King, D.; et al. (July 2011), "Copenhagen and Cancún", 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 PDF version is also available
  88. Environmental Impacts of Tourism – Global Level UNEP
  89. "search engine optimisation manchester, web design agency london, e commerce manchester". freightbestpractice.org.uk. Retrieved 13 September 2015.
  90. A practical guide for fleet operators
  91. Evans, Kimberly Masters (2005). "The greenhouse effect and climate change". The environment: a revolution in attitudes. Detroit: Thomson Gale. ISBN 0-7876-9082-1.
  92. "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.
  93. Held, I. M.; Soden, B. J. (2000). "Water Vapor Feedback and Global Warming1". Annual Review of Energy and the Environment 25: 441–475. doi:10.1146/annurev.energy.25.1.441.
  94. Includes the Kyoto "basket" of GHGs
  95. 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. 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. This citation clarifies the time period (1970–2004) for the observed emissions trends
  96. Bridging the Emissions Gap: A UNEP Synthesis Report (PDF), Nairobi, Kenya: United Nations Environment Programme (UNEP), November 2011, ISBN 978-92-807-3229-0 UNEP Stock Number: DEW/1470/NA
  97. "Global Greenhouse Gas Emissions Data". EPA. Retrieved 4 March 2014. The burning of coal, natural gas, and oil for electricity and heat is the largest single source of global greenhouse gas emissions.
  98. 1 2 "Selected Development Indicators" (PDF). World Development Report 2010: Development and Climate Change (PDF). Washington, D.C., USA: The International Bank for Reconstruction and Development / The World Bank. 2010. Tables A1 and A2. doi:10.1596/978-0-8213-7987-5. ISBN 9780821379875.
  99. 1 2 Bader, N.; Bleichwitz, R. (2009). "Measuring urban greenhouse gas emissions: The challenge of comparability. S.A.P.I.EN.S. 2 (3)". Sapiens.revues.org. Retrieved 2011-09-11.
  100. 1 2 3 4 5 6 7 8 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, USA. PDF version: IPCC website. doi:10.2277/0521568544. ISBN 978-0-521-56854-8.
  101. 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. 2007. p. 600. ISBN 978-92-64-02730-5. Retrieved 2010-05-04.
  102. 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 2011-04-20.
  103. B. Metz, O. R. Davidson, P. R. Bosch, R. Dave, L. A. Meyer, ed. (2007). "Annex I: Glossary J-P". 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, USA. This version: IPCC website. ISBN 978-0-521-88011-4. Retrieved 2011-04-11.
  104. Markandya, A. (2001). "7.3.5 Cost Implications of Alternative GHG Emission Reduction Options and Carbon Sinks". In B. Metz; et al. 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. This version: GRID-Arendal website. doi:10.2277/0521015022. ISBN 978-0-521-01502-8. Retrieved 2011-04-11.
  105. 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 2011-04-11.
  106. Botzen, W. J. W.; et al. (2008). "Cumulative CO2 emissions: shifting international responsibilities for climate debt". Climate Policy 8: 570. doi:10.3763/cpol.2008.0539.
  107. 1 2 3 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.
  108. 1 2 3 World Energy Outlook 2009 (PDF), Paris, France: International Energy Agency (IEA), 2009, pp. 179–180, ISBN 978-92-64-06130-9
  109. 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, 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
  110. The cited paper uses the term "start date" instead of "base year."
  111. 1 2 3 "Global CO2 emissions: annual increase halves in 2008". Netherlands Environmental Assessment Agency (PBL) website. 25 June 2009. Retrieved 2010-05-05.
  112. "Global Carbon Mechanisms: Emerging lessons and implications (CTC748)". Carbon Trust. March 2009. p. 24. Retrieved 2010-03-31.
  113. http://www.theguardian.com/environment/2015/dec/07/global-emissions-to-fall-for-first-time-during-a-period-of-economic-growth
  114. CO2 Emissions From Fuel Combustion: Highlights (2011 edition), Paris, France: International Energy Agency (IEA), 2011, p. 9
  115. Helm, D.; et al. (10 December 2007). Too Good To Be True? The UK's Climate Change Record (PDF). p. 3.
  116. 1 2 3 Davis, S. J. and K. Caldeira (8 March 2010). "Consumption-based Accounting of CO2 Emissions" (PDF). Proceedings of the National Academy of Sciences of the United States of America 107 (12). Bibcode:2010PNAS..107.5687D. doi:10.1073/pnas.0906974107. Retrieved 2011-04-18.
  117. "International Carbon Flows". Carbon Trust. May 2011. Retrieved 12 November 2012.
  118. 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.
  119. "International Energy Agency — Energy Policy". Paris, France: International Energy Agency (IEA). 2012.
  120. "IEA Publications Bookshop: IEA Publications on 'Energy Policy'". Paris, France: Organization for Economic Co-operation and Development (OECD) / International Energy Agency (IEA). 2012.
  121. Bridging the Emissions Gap: A UNEP Synthesis Report (PDF), Nairobi, Kenya: United Nations Environment Programme (UNEP), November 2011, ISBN 978-92-807-3229-0 UNEP Stock Number: DEW/1470/NA
  122. "4. Energizing development without compromising the climate" (PDF). World Development Report 2010: Development and Climate Change (PDF). Washington, D.C., USA: The International Bank for Reconstruction and Development / The World Bank. 2010. p 192, Box 4.2: Efficient and clean energy can be good for development. doi:10.1596/978-0-8213-7987-5. ISBN 9780821379875.
  123. 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 Framework Convention on Climate Change (UNFCCC). 2005. pp. 10–12.
  124. 1 2 3 4 Compilation and synthesis of fifth national communications. Executive summary. Note by the secretariat. (PDF). Geneva (Switzerland): United Nations Framework Convention on Climate Change (UNFCCC). 2011. pp. 9–10.
  125. Fisher, B.; et al. (2007). "3.1 Emissions scenarios". In B. Metz, O. R. Davidson, P. R. Bosch, R. Dave, L. A. Meyer. 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.
  126. 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. 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.
  127. 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. 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.
  128. carbon dioxide, methane, nitrous oxide, sulfur hexafluoride
  129. "Greenhouse Gas Emissions from a Typical Passenger Vehicle, US Environment Protection Agency" (PDF). Epa.gov. Retrieved 2011-09-11.
  130. Engber, Daniel (1 November 2006). "How gasoline becomes CO2, Slate Magazine". Slate Magazine. Retrieved 2011-09-11.
  131. "Volume calculation for carbon dioxide". Icbe.com. Retrieved 2011-09-11.
  132. "Voluntary Reporting of Greenhouse Gases Program". Energy Information Administration. Retrieved 21 August 2009.
  133. Moomaw, W., P. Burgherr, G. Heath, M. Lenzen, J. Nyboer, A. Verbruggen (2011). "Annex II: Methodology" (PDF). IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation: 10.
  134. 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.
  135. 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.
  136. 1 2 3 "Geoengineering the climate: science, governance and uncertainty". The Royal Society. 2009. Archived from the original on 7 September 2009. Retrieved 12 September 2009.
  137. 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.
  138. Cook, J.; Nuccitelli, D.; Green, S. A.; Richardson, M.; Winkler, B. R.; Painting, R.; Way, R.; Jacobs, P.; Skuce, A. (2013). "Quantifying the consensus on anthropogenic global warming in the scientific literature". Environmental Research Letters 8 (2): 024024. doi:10.1088/1748-9326/8/2/024024.

Bibliography

  • Carbon Dioxide Information Analysis Center (CDIAC), Oak Ridge, Tennessee, 2012 
  • IPCC TAR WG1 (2001), Houghton, J. T.; Ding, Y.; Griggs, D. J.; Noguer, M.; van der Linden, P. J.; Dai, X.; Maskell, K.; and Johnson, C. A., ed., Climate Change 2001: The Scientific Basis, Contribution of Working Group I (WG1) to the Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC), Cambridge University Press, ISBN 0-521-80767-0  (pb: 0-521-01495-6)
  • IPCC AR4 WG1 (2007), Solomon, S.; Qin, D.; Manning, M.; Chen, Z.; Marquis, M.; Averyt, K. B.; Tignor, M.; and Miller, H. L., ed., Climate Change 2007: The Physical Science Basis, Contribution of Working Group I (WG1) to the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), Cambridge University Press, ISBN 978-0-521-88009-1  (pb: 978-0-521-70596-7)
  • Van Dijk, P.; Zhang, J.; Jun, W.; Kuenzer, C.; WOLF, K. H. (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 86 (1 Special Issue RS/GIS): 108–119. doi:10.1016/j.coal.2011.01.009. 
  • Zhou, Yiqin (2011). Compar[ison of] Fresh or Ensiled Fodders (e.g., Grass, Legume, Corn) on the Production of Greenhouse Gases Following Enteric Fermentation in Beef Cattle. Rouyn-Noranda, Qué.: Université du Québec en Abitibi-Témiscamingue. N.B.: Research report.

External links

Carbon dioxide emissions

This article is issued from Wikipedia - version of the Thursday, May 05, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.