Greenhouse gases reach record high
Greenhouse gas levels reached record highs in 2005 and will continue to build in the atmosphere in the absence of drastic emission cuts, the UN has said.
As international delegates review progress Kyoto in Nairobi (see related story), the Annual Greenhouse gas Bulletin revealed a rise in overall concentrations despite some progress on Kyoto targets.
Carbon dioxide rose by 0.5% last year reaching 35.5% above pre-industrial levels, nitrous dioxide (N2O) went up by 0.2%, while methane concentrations stayed constant.
Between them, CO2, N2O and methane are responsible for most of the man-made warming to date, or 0.88% of the increase in the atmosphere’s heat-trapping properties. Carbon dioxide has now accumulated to a level of 379.1parts per million, compared to around 280ppm in pre-industrial times.
Even if all Kyoto targets are met, the resulting 5% cut in developing countries’ emissions from 1990 levels by 2008-12 would not be enough to put the breaks on the rise in heat-trapping gases, the WMO has said.
“To really make CO2 level off we will need more drastic measures than are in the Kyoto Protocol today,”, Geir Braathen, a senior scientist in the UN’s World Meteorological Organisation (WMO), told reporters.
Meanwhile, Kyoto signatories Canada, Spain and Italy are almost sure to miss their objectives, and the world’s biggest polluters, the US and China, remain free of binding targets. Britain is campaigning for the US, China and India to accept binding targets for the next round of negotiations.
While the CO2 build-up is largely due to humans burning fossil fuels, only 30% of the nitrous oxide increase is caused by human activities. Fuel combustion, biomass burning and fertiliser use all produce N2O. Around 60% of methane emissions come from human activities like fossil fuel combustion, rice agriculture, livestock farming and biomass burning.
Although CO2 is the most important greenhouse gas it is only responsible for 62% of the greenhouse effect observed to date.
The full WMO Greenhouse Gas Bulletin 2005 can be found here.