24 November 2010: The World Meteorological Organization’s (WMO) Global Atmosphere Watch Programme has released the Greenhouse Gas Bulletin, which tracks observations of atmospheric greenhouse gases (GHG) through 2009.

The Bulletin, which reports on the five major gases responsible for 96% of the increase in radiative forcing (carbon dioxide, methane, nitrous oxide, CFC-12 and CFC-11), finds that total radiative forcing of all long-lived GHGs increased by 27.5% from 1990 to 2009, and by 1% from 2008 to 2009, reflecting the rising atmospheric burdens of carbon dioxide, methane and nitrous oxide.

It notes that growth rates of carbon dioxide and nitrous oxide in 2009 were consistent with recent rates but were smaller than in 2008. It also highlights a recent growth in atmospheric methane levels after a decade of low emissions, which may be based on land emissions from the Northern latitudes and tropics. The Bulletin further notes that carbon dioxide levels reached 386.8 parts per million. It describes an index by the US National Oceanic and Atmospheric Administration (NOAA) that demonstrates a 27.5% increase in radiative forcing by long-lived GHG, largely due to increases in carbon dioxide. The data for the report was submitted by 48 WMO member countries, with almost 50% of the records from NOAA Cooperative Global Air Sampling Network.

Commenting on the data, Michel Jarraud, WMO Secretary-General, underlined that “GHG concentrations have reached record levels despite the economic slowdown” and that “they would have been even higher without the international action taken to reduce them.” [WMO Press Release] [WMO Bulletin]