Sinks for atmospheric methane

Methane (CH 4), an important trace gas in the atmosphere, controls numerous chemical processes and species in the troposphere and stratosphere. It is a strong greenhouse gas with a significant adverse impact upon the environment. The concentration of CH 4 in the Earth's atmosphere has been increasing at a global rate of about 1% annually during this century, and reached 1·72 ppmv (by volume) in 1990. This increase is due to increasing sources, decreasing sinks or a combination of both. In this study, the individual sinks for atmospheric CH 4 are identified and characterised. Available estimates for the strengths of these sinks are presented. The role of CH 4 in the chemistry of the atmosphere is also discussed.