Atmospheric Carbon Dioxide Levels Highest On Record

After water vapour, carbon dioxide, methane (CH₄) and nitrous oxide (N₂O) are the three most prevalent greenhouse gases in the Earth's atmosphere respectively. Greenhouse gases are some of the major drivers behind global warming and climate change.

The latest Bulletin precedes WMO's participation at the second meeting of the Parties to the Kyoto Protocol (to reduce greenhouse gas emissions), in conjunction with the twelfth session of the Conference of the Parties to the United Nations Framework Convention on Climate Change, in Nairobi from 6 to 17 November 2006.

Concentrations of N₂O also reached record highs in 2005, up 0.19 per cent from 318.6 parts per billion (ppb) to 319.2 ppb while methane remained stable at 1783 ppb.

The 35.4% rise in carbon dioxide 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 from 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.

For the full Bulletin: http://www.wmo.int/web/arep/gaw/ghg/ghgbull06.html