Geneva, Switzerland (GLOBE-Net) – Global atmospheric concentrations of carbon dioxide reached their highest levels ever recorded in 2005, reports the World Meteorological Organization. The data showing record levels of greenhouse gases in the atmosphere was released ahead of a major international meeting of the United Nations climate change body.

In 2005, global average atmospheric concentrations of carbon dioxide (CO2) were measured at 379.1 parts per million (ppm), up 0.53 per cent from 377.1 ppm in 2004. CO2 is the most prevalent greenhouse gas caused by human activities such as the combustion of fossil fuels. Levels of greenhouse gases (GHGs) have been linked to rising global temperatures.

Human combustion of fossil fuels has contributed to a 34.5 percent rise in carbon dioxide levels since the late 1700s, when large-scale industrialization began.

Levels of methane (CH4), another common greenhouse gas, were remained relatively stable at 1783 parts per billion. Methane is considered to have a much greater contribution to climate change than carbon dioxide, with a ‘global warming potential’ of 23 times that of CO2 over 100 years.

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%. Scientists are not certain why methane concentrations have leveled off in recent years.

The third most common greenhouse gas, nitrous oxide (N2O), also reached record levels in 2005, increasing from 318.6 parts ppb to 319.2 ppb. N2O has a global warming potential of 296 times that of carbon dioxide over 100 years. 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.

The WMO uses atmospheric observations from WMO members, taken from ships, aircraft, and monitoring stations to produce a yearly report on greenhouse gas concentrations in the earth’s atmosphere.

The Greenhouse Gases Bulletin is produced in cooperation with the World Data Centre for Greenhouse Gases 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.

The full WMO Greenhouse Gas Bulletin 2005 can be found “click here”.

The report was issued on the eve of a meeting of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP), which takes place in Nairobi from November 6 to 17th. COP is the major annual meeting of countries as part of multilateral climate change efforts, and is held in conjunction with a meeting of signatories to the Kyoto Protocol.