WMO Greenhouse Gas Bulletin · Overview This is the third in a series of WMO-GAW Annual Green-house...
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Overview This is the third in a series of WMO-GAW Annual Green- house Gas Bulletins. Each year, these bulletins report the latest trends and atmospheric burdens of the most influen- tial, long-lived greenhouse gases; carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O), as well as a sum- mary of the contributions of the lesser gases. These three major gases alone contribute about 88% of the increase in radiative forcing of the atmosphere by changes in long- lived greenhouse gases occurring since the beginning of the industrial age (~ 1750). The Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) promotes systematic and reliable observations of the global atmos- pheric environment, including measurements of CO 2 , CH 4 , N 2 O, and other atmospheric gases. Sites where some or all of these gases are monitored are shown in Figure 1. The measurement data are reported by participating countries and archived and distributed by the World Data Centre for Greenhouse Gases (WDCGG) at the Japan Meteorological Agency (JMA). Statistics on the present global atmospheric abundanc- es are given in Table 1. They are obtained from a global analysis method using a data set which is traceable to the WMO World Reference Standard (http://gaw.kishou. go.jp/wdcgg/products/bulletin.html ). The values in Table 1 are slightly different from those in the Fourth Assessment Report of IPCC, mainly due to the different selection of stations employed. The three major greenhouse gases have been increasing in the atmosphere since the beginning of the industrial age. Water vapour is a natural component of the climate and weather system that is indirectly affected by human activities through changes in temperature, land surface characteristics and aerosol effects on clouds. This Bul- letin focuses on those greenhouse gases that are direct- ly influenced by human activities and that are generally much longer lived in the atmosphere than water vapour. According to the NOAA Annual Greenhouse Gas Index (AGGI), the total radiative forcing by all long-lived green- house gases has increased by 22.7% since 1990 and by 1.23% from 2005 to 2006 (see Figure 2 and http://www. esrl.noaa.gov/gmd/aggi ). Carbon Dioxide (CO 2 ) CO 2 is the single most important infrared absorbing, an- thropogenic gas in the atmosphere and is responsible for 63 % of the total radiative forcing of Earth by long-lived greenhouse gases. Its contribution to the increase in ra- diative forcing is 87% for the past decade and 91% for the last five years. For about 10,000 years before the in- dustrial revolution, the atmospheric abundance of CO 2 was nearly constant at ~ 280 ppm (ppm = number of mol- ecules of the greenhouse gas per million molecules of dry air). This abundance represented a balance among large seasonal fluxes (on the order of 100 Gigatonnes (Gt) of carbon per year) between the atmosphere and bio- sphere (photosynthesis and respiration) and the atmos- phere and the ocean (physical exchange of CO 2 ). Since the late 1700s, atmospheric CO 2 has increased by 36.1%, primarily because of emissions from combustion of fos- sil fuels (currently about 8.4 Gt carbon per year) and, to and its budget of sources and sinks. Globally averaged CH 4 in 2006 was 1782 ppb, which means a decrease of 1 ppb since 2005 and a decrease of 2 ppb since 2003. (Figure 4). By contrast, methane was in- creasing by up to 13 ppb per year during the late 1980s. The average growth rate has been 2.4 ppb per year over the past ten years. Nitrous Oxide (N 2 O) Nitrous oxide (N 2 O) contributes 6.2% of the total radiative forc- ing from long-lived greenhouse gases. Its atmospheric abun- dance prior to industrialization was 270 ppb. N 2 O is emitted into the atmosphere from natu- ral and anthropogenic sources, including the oceans, soil, com- bustion of fuels, biomass burn- ing, fertiliser use, and various industrial processes. One-third of its total emissions is from anthropogenic sources. It is removed from the atmosphere by photochemical pro- cesses in the stratosphere. Globally averaged N 2 O dur- ing 2006 was 320.1 ppb, up 0.8 ppb from the year before (Figure 5). The mean growth rate has been 0.76 ppb per year over the past 10 years. Other Greenhouse Gases The ozone depleting chlorofluorocarbons (CFCs) also contribute to the radiative forcing of the atmosphere. Their overall contribution to the global radiative forcing is sig- nificant (12% of the total; http://www.esrl.noaa.gov/gmd/ aggi ). 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Radiative Forcing (W m -2 ) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Annual Greenhouse Gas Index (AGGI) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 2006: 1.227 10 Minor CFC11 CFC12 N 2 O CH 4 CO 2 a lesser extent, deforestation (~1.5 Gt carbon per year). High-precision measurements of atmospheric CO 2 begin- ning in 1958 show that the average increase of CO 2 in the atmosphere corresponds to ~ 55% of the CO 2 emitted by fossil fuel combustion. The remaining fossil fuel-CO 2 has been removed from the atmosphere by the oceans and the terrestrial biosphere. Globally averaged CO 2 in 2006 was 381.2 ppm and the increase from 2005 to 2006 was 2.0 ppm (Figure 3). This growth rate is larger than the observed average for the 1990s (~1.5 ppm/yr), mainly because of increasing emissions of CO 2 from fossil fuel combustion. Methane (CH 4 ) Methane contributes 18.6 % of the direct radiative forcing due to long-lived greenhouse gases affected by human activities. Its chemistry also indirectly affects climate by influencing tropospheric ozone and stratospheric water vapour. Methane is emitted to the atmosphere by natural processes (~ 40%, e.g., wetlands and termites) and an- thropogenic sources (~ 60%, e.g., fossil fuel exploitation, rice agriculture, ruminant animals, biomass burning, and landfills); it is removed from the atmosphere by reaction with the hydroxyl radical (OH) and has an atmospheric lifetime of ~ 9 years. Before the industrial era, atmospheric methane was at ~ 700 ppb (ppb = number of molecules of the greenhouse gas per billion (10 9 ) molecules of dry air). Increasing emissions from anthropogenic sources are re- sponsible for the factor of 2.5 increase in CH 4 . The cycling of methane, however, is complex and managing its atmos- pheric burden requires an understanding of its emissions 1 Assuming a pre-industrial mixing ratio of 280 ppm for CO 2 , 700 ppb for CH 4 and 270 ppb for N 2 O. Figure 4. Globally averaged CH 4 (a) and its growth rate (b) from 1984 to 2006. Figure 1. The WMO-GAW global greenhouse gas network for carbon dioxide. The network for methane is similar to this. Figure 2. Changes in atmospheric radiative forcing by long- lived greenhouse gases and the 2006 update of the NOAA An- nual Greenhouse Gas Index (AGGI). 1990 has been chosen as the year of reference for the Index. Figure 5. Time series of monthly mean mixing ratios of N 2 O from 1980 to 2006. Figure 3. Globally averaged CO 2 (a) and its growth rate (b) from 1983 to 2006. 330 340 350 360 370 380 390 1985 1990 1995 2000 2005 CO 2 (ppm) Year Table 1. Global abundances of key greenhouse gases as averaged over the twelve months of 2006 as well as trends from the WMO-GAW global greenhouse gas monitoring network. CO 2 (ppm) CH 4 (ppb) N 2 O (ppb) Global abundance in 2006 381.2 1782 320.1 2006 abundance relative to year 1750 1 136% 255% 119% 2005-06 absolute increase 2.0 -1 0.8 2005-06 relative increase 0.53% -0.06% 0.25% Mean annual absolute increase during last 10 years 1.93 2.4 0.76 1600 1650 1700 1750 1800 1850 1985 1990 1995 2000 2005 CH 4 (ppb) Year 300 305 310 315 320 1980 1985 1990 1995 2000 2005 N 2 O (ppb) Year 0 1 2 3 4 1985 1990 1995 2000 2005 CO 2 (ppm/yr) Year -5 0 5 10 15 20 1985 1990 1995 2000 2005 CH 4 (ppb/yr) Year Ground-based GHG Comparison Sites Ship Aircraft WMO World Data Centre for Greenhouse Gases as of 30 October 2006 While atmospheric CFCs are now decreasing slowly, some of the CFCs still have a serious impact on the atmospher- ic greenhouse effect. Some species, such as hydrochlo- rofluorocarbons (HCFCs), which are strong infrared ab- sorbers, are increasing at rapid rates, although still low in abundance. Ozone in the troposphere does not have a long lifetime, but it has an atmospheric greenhouse effect that is comparable to those of the CFCs. Although trop- ospheric ozone is important for the atmospheric green- house effect, it is difficult to estimate the global distribution and trend due to its very uneven geographic distribution. All the gases mentioned here are also monitored as part of the WMO-GAW network. Distribution of the bulletins The Secretariat of the World Meteorological Organization (WMO) prepares and distributes Bulletins in cooperation with the World Data Centre for Greenhouse Gases at the Japan Meteorological Agency and the GAW Scientific Advisory Group for Greenhouse Gases, with the assist- ance of the NOAA Earth System Research Laboratory. The Bulletins are available through the Global Atmos- phere Watch programme web page at http://www.wmo. int/pages/prog/arep/gaw/gaw_home_en.html , and on the home pages of WDCGG (http://gaw.kishou.go.jp/wdcgg. html ) and the NOAA Carbon Cycle Greenhouse Gases Group (http://www.esrl.noaa.gov/gmd/ccgg ). Acknowledgements and links Forty-four countries are registered in GAWSIS as hav- ing contributed CO 2 data to the GAW WDCGG. Of these, many are associated with the NOAA Cooperative Global Air Sampling Network. NOAA-supported sites represent approximately 70% of the countries submitting data to GAW. The rest of the network is maintained by Austral- ia, Canada, China, Japan and many European countries (see the national reports in GAW Report #168 from the Sept. 2005 Experts Meeting). All of the WMO Global At- mosphere Watch (GAW) monitoring stations contributing to the data used in this Bulletin are shown on the map (Figure 1) and listed in the List of Contributors on the WD- CGG web page at (http://gaw.kishou.go.jp/wdcgg.html ). They are also described in the GAW Station Information System (GAWSIS) (http://www.empa.ch/gaw/gawsis/ ) op- erated by Switzerland. Contacts 1. World Meteorological Organization, Environment Divi- sion, Atmospheric Research and Environment Pro- gramme, Geneva. E-mail: [email protected] Web site: http://www.wmo.int/pages/prog/arep/gaw/ gaw_home_en.html 2. World Data Centre for Greenhouse Gases, Japan Meteorological Agency, Tokyo. E-mail: [email protected] Web site: http://gaw.kishou.go.jp/wdcgg.html Selected greenhouse gas observatories The GAW Global Observatory at Mace Head, operated by the University of Galway, is located on the west coast of Ireland. Its ex- posure to the North Atlantic Ocean makes it an ideal location to study both natural and man-made trace constituents in marine and continental air masses. A small two-engine aircraft is equipped by USA's National Oceanic and Atmospheric Administration for measurements of greenhouse gases. The GAW Global Observatory at Mt. Waliguan (3810 masl) in Western China is operated by the Chinese Meteorological Administration. Its location on a mountain top and far away from big cities makes it an ideal site for global pollution monitoring. The ESA-operated ENVISAT satellite, which carries the SCIAMACHY instrument, measures total column methane and several other parameters. WMO Greenhouse Gas Bulletin The State of Greenhouse Gases in the Atmosphere Using Global Observations through 2006 L.A. Barrie 1 , G.O. Braathen 1 , J.H. Butler 2 , E. Dlugokencky 2 , D.J. Hofmann 2 , P. Tans 2 , Y. Tsutsumi 3 1 World Meteorological Organization, 2 Earth System Research Laboratory/National Oceanic and Atmospheric Administration, 3 Japanese Meteorological Agency and the WMO World Data Centre for Greenhouse Gases Column averaged CO 2 mixing ratio (ppm) for 1 February 2005 calculated from NOAA's CarbonTracker model (see: http://www. esrl.noaa.gov/gmd/ccgg/carbontracker/) and measurements from a number of sites in the WMO-GAW Global CO 2 network described in this Bulletin. Blue regions have relatively low CO 2 and red regions have relatively high CO 2 . High CO 2 values, mostly from fossil fuel combustion, are observed over North America, Europe and East Asia. The passage of a frontal system is seen between eastern Europe and Asia. CO 2 from a biomass burning plume is being transported from Equatorial Africa towards the Atlantic Ocean. 374 376 378 380 CO 2 [ppm] Executive summary The latest analysis of data from the WMO-GAW Global Greenhouse Gas Monitoring Network shows that the globally averaged mixing ratios of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) have reached new highs in 2006 with CO 2 at 381.2 ppm and N 2 O at 320.1 ppb. Atmospheric growth rates in 2006 of these gases are consistent with recent years. The mixing ratio of methane (CH 4 ) remains almost unchanged at 1782 ppb. These values are higher than those in pre-industrial times by 36%, 19% and 155%, respectively. Methane growth has slowed during the past decade. The NOAA Annual Greenhouse Gas Index (AGGI) shows that from 1990 to 2006 the atmospheric radiative forcing by all long-lived greenhouse gases has increased by 22.7%. The combined radiative forcing by CFC- 11 and CFC-12 exceeds that of N 2 O. They are decreasing very slowly as a result of emission reduc- tions under the Montreal Protocol on Substances That Deplete the Ozone Layer. Carbon Tracker 2007 release NOAA Earth System Research Laboratory U . S . D E P A R T M E N T O F C O M M E R C E N A T I O N A L O C E A N I C A N D A T M O S P H E R I C A D M I N I S T R A T I O N
Transcript of WMO Greenhouse Gas Bulletin · Overview This is the third in a series of WMO-GAW Annual Green-house...
Overview This is the third in a series of WMO-GAW Annual Green-house Gas Bulletins. Each year, these bulletins report the latest trends and atmospheric burdens of the most influen-tial, long-lived greenhouse gases; carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as a sum-mary of the contributions of the lesser gases. These three major gases alone contribute about 88% of the increase in radiative forcing of the atmosphere by changes in long-lived greenhouse gases occurring since the beginning of the industrial age (~ 1750).The Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) promotes systematic and reliable observations of the global atmos-pheric environment, including measurements of CO2, CH4, N2O, and other atmospheric gases. Sites where some or all of these gases are monitored are shown in Figure 1. The measurement data are reported by participating countries and archived and distributed by the World Data Centre for Greenhouse Gases (WDCGG) at the Japan Meteorological Agency (JMA). Statistics on the present global atmospheric abundanc-es are given in Table 1. They are obtained from a global analysis method using a data set which is traceable to the WMO World Reference Standard (http://gaw.kishou.
go.jp/wdcgg/products/bulletin.html). The values in Table 1 are slightly different from those in the Fourth Assessment Report of IPCC, mainly due to the different selection of stations employed.The three major greenhouse gases have been increasing in the atmosphere since the beginning of the industrial age. Water vapour is a natural component of the climate and weather system that is indirectly affected by human activities through changes in temperature, land surface characteristics and aerosol effects on clouds. This Bul-letin focuses on those greenhouse gases that are direct-ly influenced by human activities and that are generally much longer lived in the atmosphere than water vapour.According to the NOAA Annual Greenhouse Gas Index (AGGI), the total radiative forcing by all long-lived green-house gases has increased by 22.7% since 1990 and by 1.23% from 2005 to 2006 (see Figure 2 and http://www.esrl.noaa.gov/gmd/aggi).
Carbon Dioxide (CO2)CO2 is the single most important infrared absorbing, an-thropogenic gas in the atmosphere and is responsible for 63 % of the total radiative forcing of Earth by long-lived greenhouse gases. Its contribution to the increase in ra-diative forcing is 87% for the past decade and 91% for the last five years. For about 10,000 years before the in-dustrial revolution, the atmospheric abundance of CO2 was nearly constant at ~ 280 ppm (ppm = number of mol-ecules of the greenhouse gas per million molecules of dry air). This abundance represented a balance among large seasonal fluxes (on the order of 100 Gigatonnes (Gt) of carbon per year) between the atmosphere and bio-sphere (photosynthesis and respiration) and the atmos-phere and the ocean (physical exchange of CO2). Since the late 1700s, atmospheric CO2 has increased by 36.1%, primarily because of emissions from combustion of fos-sil fuels (currently about 8.4 Gt carbon per year) and, to
and its budget of sources and sinks. Globally averaged CH4 in 2006 was 1782 ppb, which means a decrease of 1 ppb since 2005 and a decrease of 2 ppb since 2003. (Figure 4). By contrast, methane was in-creasing by up to 13 ppb per year during the late 1980s. The average growth rate has been 2.4 ppb per year over the past ten years.
Nitrous Oxide (N2O)Nitrous oxide (N2O) contributes 6.2% of the total radiative forc-ing from long-lived greenhouse gases. Its atmospheric abun-dance prior to industrialization was 270 ppb. N2O is emitted into the atmosphere from natu-ral and anthropogenic sources, including the oceans, soil, com-bustion of fuels, biomass burn-ing, fertiliser use, and various industrial processes. One-third
of its total emissions is from anthropogenic sources. It is removed from the atmosphere by photochemical pro-cesses in the stratosphere. Globally averaged N2O dur-ing 2006 was 320.1 ppb, up 0.8 ppb from the year before (Figure 5). The mean growth rate has been 0.76 ppb per year over the past 10 years.
Other Greenhouse GasesThe ozone depleting chlorofluorocarbons (CFCs) also contribute to the radiative forcing of the atmosphere. Their overall contribution to the global radiative forcing is sig-nificant (12% of the total; http://www.esrl.noaa.gov/gmd/aggi).
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a lesser extent, deforestation (~1.5 Gt carbon per year). High-precision measurements of atmospheric CO2 begin-ning in 1958 show that the average increase of CO2 in the atmosphere corresponds to ~ 55% of the CO2 emitted by fossil fuel combustion. The remaining fossil fuel-CO2 has been removed from the atmosphere by the oceans and the terrestrial biosphere. Globally averaged CO2 in 2006 was 381.2 ppm and the increase from 2005 to 2006 was 2.0 ppm (Figure 3). This growth rate is larger than the observed average for the 1990s (~1.5 ppm/yr), mainly because of increasing emissions of CO2 from fossil fuel combustion.
Methane (CH4)Methane contributes 18.6 % of the direct radiative forcing due to long-lived greenhouse gases affected by human activities. Its chemistry also indirectly affects climate by influencing tropospheric ozone and stratospheric water vapour. Methane is emitted to the atmosphere by natural processes (~ 40%, e.g., wetlands and termites) and an-thropogenic sources (~ 60%, e.g., fossil fuel exploitation, rice agriculture, ruminant animals, biomass burning, and landfills); it is removed from the atmosphere by reaction with the hydroxyl radical (OH) and has an atmospheric lifetime of ~ 9 years. Before the industrial era, atmospheric methane was at ~ 700 ppb (ppb = number of molecules of the greenhouse gas per billion (109) molecules of dry air). Increasing emissions from anthropogenic sources are re-sponsible for the factor of 2.5 increase in CH4. The cycling of methane, however, is complex and managing its atmos-pheric burden requires an understanding of its emissions 1 Assuming a pre-industrial mixing ratio of 280 ppm for CO2, 700 ppb for CH4 and 270 ppb for N2O.
Figure 4. Globally averaged CH4 (a) and its growth rate (b) from 1984 to 2006.
Figure 1. The WMO-GAW global greenhouse gas network for carbon dioxide. The network for methane is similar to this.
Figure 2. Changes in atmospheric radiative forcing by long-lived greenhouse gases and the 2006 update of the NOAA An-nual Greenhouse Gas Index (AGGI). 1990 has been chosen as the year of reference for the Index.
Figure 5. Time series of monthly mean mixing ratios of N2O from 1980 to 2006.
Figure 3. Globally averaged CO2 (a) and its growth rate (b) from 1983 to 2006.
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Table 1. Global abundances of key greenhouse gases as averaged over the twelve months of 2006 as well as trends from the WMO-GAW global greenhouse gas monitoring network.
CO2 (ppm) CH4 (ppb) N2O (ppb)
Global abundance in 2006 381.2 1782 320.1
2006 abundance relative to year 17501
136% 255% 119%
2005-06 absolute increase 2.0 -1 0.8
2005-06 relative increase 0.53% -0.06% 0.25%
Mean annual absolute increase during last 10 years
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Aircraft WMO World Data Centrefor Greenhouse Gasesas of 30 October 2006
While atmospheric CFCs are now decreasing slowly, some of the CFCs still have a serious impact on the atmospher-ic greenhouse effect. Some species, such as hydrochlo-rofluorocarbons (HCFCs), which are strong infrared ab-sorbers, are increasing at rapid rates, although still low in abundance. Ozone in the troposphere does not have a long lifetime, but it has an atmospheric greenhouse effect that is comparable to those of the CFCs. Although trop-ospheric ozone is important for the atmospheric green-house effect, it is difficult to estimate the global distribution and trend due to its very uneven geographic distribution. All the gases mentioned here are also monitored as part of the WMO-GAW network.
Distribution of the bulletinsThe Secretariat of the World Meteorological Organization (WMO) prepares and distributes Bulletins in cooperation with the World Data Centre for Greenhouse Gases at the Japan Meteorological Agency and the GAW Scientific Advisory Group for Greenhouse Gases, with the assist-ance of the NOAA Earth System Research Laboratory. The Bulletins are available through the Global Atmos-phere Watch programme web page at http://www.wmo.int/pages/prog/arep/gaw/gaw_home_en.html, and on the home pages of WDCGG (http://gaw.kishou.go.jp/wdcgg.html) and the NOAA Carbon Cycle Greenhouse Gases Group (http://www.esrl.noaa.gov/gmd/ccgg).
Acknowledgements and linksForty-four countries are registered in GAWSIS as hav-ing contributed CO2 data to the GAW WDCGG. Of these, many are associated with the NOAA Cooperative Global Air Sampling Network. NOAA-supported sites represent approximately 70% of the countries submitting data to GAW. The rest of the network is maintained by Austral-ia, Canada, China, Japan and many European countries (see the national reports in GAW Report #168 from the Sept. 2005 Experts Meeting). All of the WMO Global At-mosphere Watch (GAW) monitoring stations contributing to the data used in this Bulletin are shown on the map (Figure 1) and listed in the List of Contributors on the WD-CGG web page at (http://gaw.kishou.go.jp/wdcgg.html). They are also described in the GAW Station Information System (GAWSIS) (http://www.empa.ch/gaw/gawsis/) op-erated by Switzerland.
Contacts1. World Meteorological Organization, Environment Divi-
sion, Atmospheric Research and Environment Pro-gramme, Geneva. E-mail: [email protected] Web site: http://www.wmo.int/pages/prog/arep/gaw/gaw_home_en.html
2. World Data Centre for Greenhouse Gases, Japan Meteorological Agency, Tokyo. E-mail: [email protected] Web site: http://gaw.kishou.go.jp/wdcgg.html
Selected greenhouse gas observatories
The GAW Global Observatory at Mace Head, operated by the University of Galway, is located on the west coast of Ireland. Its ex-
posure to the North Atlantic Ocean makes it an ideal location to study both natural and man-made trace constituents in marine and
continental air masses.
A small two-engine aircraft is equipped by USA's National Oceanic and Atmospheric Administration for measurements of
greenhouse gases.
The GAW Global Observatory at Mt. Waliguan (3810 masl) in Western China is operated by the Chinese Meteorological Administration. Its location on a mountain top and far away from big cities makes it an
ideal site for global pollution monitoring.
The ESA-operated ENVISAT satellite, which carries the SCIAMACHY instrument, measures total column methane and
several other parameters.
WMO Greenhouse Gas BulletinThe State of Greenhouse Gases in the Atmosphere Using Global Observations through 2006
L.A. Barrie1, G.O. Braathen1, J.H. Butler2, E. Dlugokencky2, D.J. Hofmann2, P. Tans2, Y. Tsutsumi31World Meteorological Organization, 2Earth System Research Laboratory/National Oceanic and Atmospheric Administration, 3Japanese Meteorological Agency
and the WMO World Data Centre for Greenhouse Gases
Column averaged CO2 mixing ratio (ppm) for 1 February 2005 calculated from NOAA's CarbonTracker model (see: http://www.esrl.noaa.gov/gmd/ccgg/carbontracker/) and measurements from a number of sites in the WMO-GAW Global CO2 network described in this Bulletin. Blue regions have relatively low CO2 and red regions have relatively high CO2. High CO2 values, mostly from fossil fuel combustion, are observed over North America, Europe and East Asia. The passage of a frontal system is seen between eastern Europe and Asia. CO2 from a biomass burning plume is being transported from Equatorial Africa towards the Atlantic Ocean.
374 376 378 380
CO2 [ppm]
Executive summaryThe latest analysis of data from the WMO-GAW Global Greenhouse Gas Monitoring Network shows that the globally averaged mixing ratios of carbon dioxide (CO2) and nitrous oxide (N2O) have reached new highs in 2006 with CO2 at 381.2 ppm and N2O at 320.1 ppb. Atmospheric growth rates in 2006 of these gases are consistent with recent years. The mixing ratio of methane (CH4 ) remains almost unchanged at 1782 ppb. These values are higher than those in pre-industrial times by 36%, 19% and 155%, respectively. Methane growth has slowed during the past decade. The NOAA Annual Greenhouse Gas Index (AGGI) shows that from 1990 to 2006 the atmospheric radiative forcing by all long-lived greenhouse gases has increased by 22.7%. The combined radiative forcing by CFC-11 and CFC-12 exceeds that of N2O. They are decreasing very slowly as a result of emission reduc-tions under the Montreal Protocol on Substances That Deplete the Ozone Layer.
Carbon Tracker 2007 releaseNOAA Earth System Research Laboratory
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