Methane levels in the atmosphere have more than doubled since pre-industrial times. Until recently, the leveling off of methane levels had suggested that the rate of its emission from the Earth's surface was approximately balanced by the rate of its destruction in the atmosphere.
However, since early 2007 the balance has been upset, according to a paper on the new findings being published this week in Geophysical Review Letters. This imbalance has resulted in several million metric tons of additional methane in the atmosphere, the authors reported.
Methane is produced by wetlands, rice paddies, cattle, and the gas and coal industries, and is destroyed by reaction with the hydroxyl free radical (OH), often referred to as the atmosphere's "cleanser". One surprising feature of this recent growth is that it occurred almost simultaneously at all measurement locations across the globe….Methane wafts up from this terraced rice field in Yunnan Province, China, shot by Jialiang Gao, www.peace-on-earth.org, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2