ASSESSMENT OF UNCERTAINTIES IN THE PROJECTED CONCENTRATIONS OF METHANE IN THE ATMOSPHERE, (TECHNICAL REPORT)

Sinks and sources of methane have been examined in the papers presente d at the IUPAC sponsored Workshop held in Moscow in July 1992. The con clusion reached was that very large uncertainties exist in the assessm ent of sources. The emissions from wetlands and rice paddies could be much lower than formerly assumed. The emissions from other sources, e. g. from landfills, could be larger. The most important sink, oxidation by OH-radicals in the atmosphere, has an uncertainty of 40% or more a nd cannot be used to evaluate the quality of the emission data. As a c onsequence, it is very difficult to predict future atmospheric concent rations, as function of changes in land use and economic activities. T he prediction of the radiative balance of the earth is very difficult not only because of the uncertainty in future greenhouse gas concentra tions but also because important factors, like the influence of aeroso ls, are insufficiently characterized.