Peter Cox at the University of Exeter said the world could garner 15 years of breathing space for fighting climate change by widening its attack on greenhouse gases -- mostly concerned with carbon dioxide -- and concentrate on methane, the second-most significant greenhouse gas.
"Methane is a more important control on global temperature than previously realized," Cox said at the Planet Under Pressure conference in London. "The gas' influence is much greater than its direct effect on the atmosphere."
Cox has examined the way both CO2 and methane influence plant growth, and says action to reduce methane could have twice the expected affect in controlling climate change.
An atmosphere containing less methane but more CO2 would encourage forests and other vegetation on land to absorb more carbon, he said, as the extra CO2 would act as a fertilizer for vegetation, which would grow faster and absorb more CO2.
Also, less methane would reduce the creation of tropospheric ozone, which damages plant growth.
A 40 percent reduction in human-caused methane emissions would permit the release of an extra 500 gigatons of carbon dioxide -- a third more than previously thought -- before the planet exceeds the 2 degree centigrade (3.6 Fahrenheit) warming considered the threshold for dangerous climate change.
"That is a 15-year breathing space at current CO2 emission rates," Cox told NewScientist.com.
Most governments have become fixated on combating CO2 emissions while the benefits of action on other greenhouses gases have been ignored, he said.