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You are here: Home / Data and maps / Indicators / Atmospheric greenhouse gas concentrations / Atmospheric greenhouse gas concentrations (CSI 013/CLIM 052) - Assessment published Jan 2013

Atmospheric greenhouse gas concentrations (CSI 013/CLIM 052) - Assessment published Jan 2013

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Generic metadata

Topics:

Climate change Climate change (Primary topic)

Tags:
greenhouse gases | climate change | csi | kyoto protocol
DPSIR: State
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • CSI 013
  • CLIM 052
Dynamic
Temporal coverage:
1750-2010
 
Contents
 

Key policy question: What is the trend of greenhouse gas concentrations in the atmosphere? Will they remain below 450 ppm CO2-equivalent to give a 50% probability that the global temperature rise will not exceed 2 degrees Celsius above pre-industrial levels?

Key messages

  • The global average concentrations of various greenhouse gases in the atmosphere have reached the highest levels ever recorded, and concentrations are increasing. The combustion of fossil fuels from human activities and land-use changes are largely responsible for this increase.
  • The concentration of all GHGs, including cooling aerosols that are relevant in the context of the 2oC temperature target, reached a value of 403 ppm CO2 equivalents in 2010, exceeding the 400 ppm for first time.
  • The concentration in 2010 of the six greenhouse gases (GHG) included in the Kyoto Protocol has reached 444 ppm CO2 equivalent, an increase of 165 ppm (around +60 %) compared to pre-industrial levels.
  • The concentration of CO2, the most important greenhouse gas, reached a level of 389 ppm by 2010, and further increased to 391 ppm in 2011. This is an increase of approximately 112 ppm (around +40 %) compared to pre-industrial levels. 

Contribution of the different GHGs to the overall greenhouse gas concentration in 1950, 1990 and 2010

Note: Contribution of the different GHGs as included in the Kyoto and Montreal protocol to the overall greenhouse gas concentration in 1950, 1990 and 2010.

Data source:
Downloads and more info

Atmospheric concentration of Carbon Dioxide (ppm)

Note: The figure shows the global atmospheric concentration of carbon dioxide up to 2010. The value for 2011 is 390.9 ppm but is not included in the chart to ensure consistency with the other greenhouse gas figures.

Data source:
Downloads and more info

Atmospheric concentration of Methane (ppb)

Note: The figure shows the global atmospheric concentration of methane up to 2010.

Data source:
Downloads and more info

Atmospheric concentration of Nitrous Oxide (ppb)

Note: The figure shows the global atmospheric concentration of nitrous oxide up to 2010.

Data source:
Downloads and more info

Key assessment

The concentration of greenhouse gases (GHG) in the atmosphere has increased during the 20th century and first part of the 21st century, extremely likely[1] caused mainly by human activities related to the use of fossil fuels (e.g. for electric power generation), agricultural activities and land-use change (mainly deforestation) (IPCC, 2007, see also Carbon Budget at Global Carbon Project). The increase of all GHG gases has been particularly rapid since 1950. The first 50 ppm increase above the pre-industrial value of carbon dioxide (CO2), the most important human greenhouse gas,- was reached in the 1970s more than 200 years since pre-industrial times, whereas the second 50 ppm increase occurred after just approximately 30 years.

The various greenhouse gases (Text box 1) affect the climate system differently (see also ‘Justification for Indicator Selection’ section). To evaluate the GHG concentration in the atmosphere in relation to temperature change, it is important to consider all greenhouse gases, i.e. the long-living GHGs under the Kyoto Protocol, those under the Montreal Protocol (direct and indirect), as well as ozone, water vapour and aerosols (IPCC, 2007). Considering these gases, the total CO2-equivalent concentration reached a level of 403 ppm CO2 eq. in 2010[2], exceeding the 400 ppm for first year (Figure 1).  The annual concentration increase has accelerated to 3.2 ppm CO2 eq.yr-1 in 2010, but the rate of increase is still lower than in earlier years. 

The contribution of tropospheric (ground-level) ozone to the climate system is considered to be stable over the recent decades when comparing large annual and special variation (IPCC, 2007a). However, long-term data on tropospheric ozone are difficult to assess due to the scarcity of representative observing sites with long records and the large spatial heterogeneity (IPCC, 2007a).

Overall, assuming a concentration threshold of 450 ppm CO2 equivalents will result in a 2oC temperature change (see ‘Justification for Indicator Selection’ section), means GHG concentrations can only increase by a further 50 ppm before this threshold value is exceeded. Assuming the 2000-2010 trend of annual increase of total GHG concentrations will continue in the coming years, the threshold value may be exceeded in less than 25 years. The lower band of the uncertainty range has been exceeded already in 2010, whereas it may take more than 50 years before the upper uncertainty band is exceeded.

Text box 1: Greenhouse gases and their inclusion in international legislation
Greenhouse gases (GHG) can intercept solar radiation and thus affect the Earth's climate system. In order to control the anthropogenic emissions of such gases, many of them are included within different international agreements, including the UNEP Montreal Protocol on Substances that deplete the Ozone layer (1987) and the Kyoto Protocol to the UNFCCC which aims to limit global warming (1997).     

(1) GHG included in the Kyoto Protocol are: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and three fluorinated gasses (HFC, PFC, SF6).
(2) GHGs in the Montreal Protocol include three other groups of fluorinated gases: CFCs, HCFCs and CH3CCl3.    
(3) In addition, GHGs exist that are not included in global treaties, here called non-protocol gases (NPG), including stratospheric and tropospheric ozone (O3), aerosols such as black carbon, and water vapour. 

Excluding water vapour, ozone and aerosols, the total concentration of the remaining, long-lived GHGs has increased from 278 in pre-industrial times to 466 ppm CO2 equivalents in 2010. This is about 188 ppm higher than pre-industrial levels. That this concentration is higher than when all gases are considered is caused by the overall cooling effect of aerosols - although certain aerosols act in an opposite manner by enhancing the warming. Overall, aerosols are compensating for around 45% of the current warming induced by the Kyoto and Montreal GHGs. Aerosols have a relatively short lifetime in the atmosphere. The Montreal Protocol gases contributed as a group about 10% to the current warming (Figure 3). The concentrations of these gases have peaked around the end of the last millennium and have now started to decline due to natural removal processes (IPCC, 2007a).

Six GHGs are included in the Kyoto Protocol. Their concentration in the atmosphere has reached 444 ppm CO2-equivalent in 2010, an increase of about 165 ppm compared to pre-industrial times (Figure 1). Changes in atmospheric CO2 contributed by far most of the increase (about 67% of the increase from pre-industrial period). When translating the overall 450 ppm CO2-equivalent limit into a limit just for the Kyoto gases (491 ppm), this means only an additional 47 ppm CO2-equivalent increase is possible (with an uncertainty range of  -2 – 97 ppm CO2-equivalent).

The concentrations of the individual GHGs under the Kyoto protocol have reached new levels in 2010 (Figures 4, 5 and 6):

  • The CO2 concentration reached a level of 389 ppm in that year, and increased further in 2011 to 391 ppm (Figure 4). This is an increase of about 112 ppm (+39%) compared to the pre-industrial levels (i.e. before 1750) (NOAA, 2012). The present CO2 concentration has not been exceeded during the past 420 000 years and possibly not even during the past 15 million years (Tripati et al., 2009). 
  • The concentration of methane (CH4) has increased to 1810 parts per billion (ppb) in 2010 (+159% from pre-industrial levels), a value which also has not been exceeded during the past 420 000 years (Figure 5). Atmospheric concentrations of CH4 have increased notably during the past couple of years. The reasons for this renewed growth are not yet fully understood, but human-induced sources such as growing industrialisation in Asia, increasing wetland emissions due to land-use changes, biomass burning, as well as increases from natural sources from northern latitudes and the tropics (e.g. CH4 releases from thawing permafrost) (Dlugokencky et al., 2009; Mascarelli, 2009; Shakhova et al, 2010) are considered potential causes (WMO, 2010). 
  • The nitrous oxide (N2O) concentration in 2010 was 323 ppb (Figure 6), 20% above the pre-industrial level. This concentration has not been exceeded during at least the past 1 000 years.  
  • The concentrations of the F-gases within the scope of the Kyoto Protocol (HFCs, PFCs and SF6) have increased by large factors (between 1.3 and 6.4, depending on the gas) between 1999 and 2010. These gases are very effective absorbers of radiation and even small amounts can significantly affect the climate system. Their contribution to the total climate forcing is rapidly increasing in the past years.

[1] Defined as >95% probability (IPCC, 2007).

[2] More recent data are not available for the annual-average concentration except for CO2, for which data for 2011 are available.

Data sources

More information about this indicator

See this indicator specification for more details.

Contacts and ownership

EEA Contact Info

John Van Aardenne

Ownership

EEA Management Plan

2012 2.4.1 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled every 1 year in January-March (Q1)
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