Gei 2011

WMO GREENHOUSE GAS BULLETIN
The State of Greenhouse Gases in the Atmosphere Based on Global Observations through 2011
No. 8 | 19 November 2012
ISSN 2078-0796
Total CO2 Observed CO2

430

7.5 5.0

Emissions CO2 increase Sink

CO2 (ppm)

PgC yr–1

400 370 340

2.5 0 –2.5 –5.0

1960

1970

1980 1990 Year

2000

2010

1960

1970

1980 1990 Year

2000

2010Since the industrial revolution, about 375 billion tonnes of carbon have been emitted by humans into the atmosphere as carbon dioxide (CO2 ). Atmospheric measurements show that about half of this CO2 remains in the atmosphere and that, so far, the ocean and terrestrial sinks have steadily increased. Accurate measurements of atmospheric CO2 by WMO/GAW partners provide the basis for understanding thefate of CO2 that has been emitted to the atmosphere. The figure (left) shows globally averaged CO2 since 1958 inferred from measurements by GAW partners (blue) and as estimated in the absence of oceanic and terrestrial sinks (green). The figure (right) shows the

annual emissions in PgC [1] from fossil fuel combustion and other industrial processes, the annual atmospheric increase, and the amountof carbon sequestered by sinks each year. These sinks constitute the small net difference between large fluxes (~100 PgC per year) into and out of the atmosphere from the terrestrial biosphere and oceans. This small net difference varies with climate oscillations, such as El Niño and La Niña events. The ocean sink is less susceptible to human interference than the terrestrial biosphere. Netuptake of CO2 by the ocean makes it more acidic with potentially large impacts on the ocean food chain. (The figures and text are based on Ballantyne et al., 2012 and Levin, 2012.)

Executive summary
The latest analysis of observations from the WMO Global Atmosphere Watch (GAW) Programme shows that the globally averaged mole fractions of carbon dioxide (CO2 ), methane (CH4 ) and nitrous oxide (N2O)reached new highs in 2011, with CO2 at 390.9±0.1 ppm [2] , CH4 at 1813±2 ppb [3] and N2O at 324.2±0.1 ppb. These values constitute 140%, 259% and 120% of pre-industrial (before 1750) levels, respectively. The atmospheric increase of CO2 from 2010 to 2011 is similar to the average growth rate over the past 10 years. However, for N2O the increase from 2010 to 2011 is greater than both the oneobserved from 2009 to 2010 and

the average growth rate over the past 10 years. Atmospheric CH4 continued to increase at a similar rate as observed over the last 3 years. The NOAA Annual Greenhouse Gas Index shows that from 1990 to 2011 radiative forcing by long-lived greenhouse gases increased by 30%, with CO2 accounting for about 80% of this increase.

Overview
This eighth WMO/GAW Annual Bulletinreports on the atmospheric burdens and rates of change of the most important long-lived greenhouse gases (LLGHGs) – carbon dioxide, methane, nitrous oxide, CFC-12 and CFC-11 – and

provides a summary of the contributions of the other gases. These five major gases account for approximately 96% [4] of radiative forcing due to LLGHGs (Figure 1). The WMO Global Atmosphere Watch Programme(http://www.wmo.int/gaw) coordinates the systematic observations and analysis of greenhouse gases and other trace species. Sites where greenhouse gases are monitored are shown in Figure 2. 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.
Ground-based Aircraft Ship GHG comparisonsites

The table provides globally averaged atmospheric abundances of the three major LLGHGs in 2011 and changes in these abundances since 2010 and 1750. The results are obtained from a global analysis of datasets (WMO, 2009) that are traceable to the WMO World Reference Standards. Data from mobile stations, with the exception of NOAA flask sampling in the Pacific (blue triangles in Figure 2),...