clipped from: www.abc.net.au   
Dani Cooper

Methane levels in the atmosphere have started to rise after almost eight years of near-zero growth, an international study says.

rice field

And the increase may lead to an acceleration of global warming, the scientists behind the study warn.

Dr Paul Fraser of the CSIRO, who co-authored the study that appears in Geophysical Research Letters, says samples taken from 12 stations across a global network showed a trend upwards in methane levels.

After seven years [of zero growth] methane has started to rise again to growth rates of the early 1990s
If methane concentrations continue to grow at the current rate then it will be once again the second-most important greenhouse gas to control after CO2 over the next few decades

Fraser says methane accounts for about 20% of all greenhouse gases since the industrial revolution.

It is 20 times more potent than carbon dioxide as a greenhouse gas and comes from sources such as natural wetlands, rice fields, fires, coal mines and natural gas reticulation.