The world's longest continuous methane and ethane sampling study may have determined why global levels of methane have tapered off dramatically in recent years.
A University of California Irvine-led science team has determined that the trapping and sale of natural gas for use as a fuel source sharply reduced the skyward venting and flaring of methane from oil fields.
“We can now say with confidence that, based on our data, the trend is largely a result of changes in fossil fuel use,” said chemistry professor Donald Blake, a senior author on the paper, in a release to media.
The study says increased capture of natural gas from oil fields may account for up to 70 per cent of the dramatic leveling off seen in atmospheric methane from the 1980s through to 2005.
Since 2007, methane levels have started to climb again. Less natural gas from oil fields and changing fertilizer and water practices in rice paddies have been suspected as causes by scientists.
The Irvine research group notes that methane has 20 times the global warming potential of carbon dioxide, although CO2 is filling the atmosphere in far larger amounts.
"It used to just be burned off as a waste product," announced lead author Isobel Simpson, a UCI research associate. "The reason this is important is because methane is a potent greenhouse gas, second in importance only to carbon dioxide. We can't make real progress on climate change without tackling carbon dioxide, but bringing methane under control would certainly help."
Methane is the main ingredient in natural gas.