|Column averaged CO2 mixing ratio (ppm) for 1 February 2005 calculated from NOAA’s CarbonTracker model and measurements from a number of sites in the WMO-GAW Global CO2 network described in the Bulletin. Blue regions have relatively low CO2 and red regions have relatively high CO2. Click to enlarge.|
In 2006, globally averaged concentrations of carbon dioxide (CO2) and nitrous oxide (N2O) in the atmosphere reached new highs with CO2 at 381.2 ppm and N2O at 320.1 ppb, according to the just-published World Meteorological Organization’s (WMO) 2006 Greenhouse Gas Bulletin. 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. Atmospheric growth rates in 2006 of CO2 and N2O gases are consistent with recent years. Methane growth has slowed during the past decade.
The information is based on observations from the WMO Global CO2 and CH4 Monitoring Network, a comprehensive climate network recognized by the United Nations Framework Convention on Climate Change.
After water vapor, carbon dioxide, methane (CH4) and nitrous oxide (N2O) are the three most prevalent greenhouse gases in the Earth’s atmosphere respectively.
The 36% rise in CO2 since the late 1700s has largely been generated by emissions from the combustion of fossil fuels. Around one third of N2O discharged into the air is a result of human activities such as fuel combustion, biomass burning, fertilizer use and some industrial processes. Human activity such as fossil fuel exploitation, rice agriculture, biomass burning, landfills and ruminant farm animals account for some 60% of atmospheric CH4, with natural processes including those produced by wetlands and termites responsible for the remaining 40%.
Accurate atmospheric observations made globally by some 44 WMO Members are archived and distributed by the World Data Centre for Greenhouse Gases (WDCGG), located at the Japan Meteorological Agency.
WMO prepares the Greenhouse Gases Bulletin in cooperation with WDCGG and the Global Atmosphere Watch Scientific Advisory Group for Greenhouse Gases with the assistance of the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory (NOAA-ESRL).
Enhancing the monitoring effort was the 2007 launch by the United States’ National Oceanic and Atmospheric Administration (NOAA) of CarbonTracker, a global carbon cycle modelling tool that converts surface-based global greenhouse gas observations into best estimates of global distribution in the atmosphere and the net air-surface exchange of carbon dioxide.