Fracking has caused a sharp rise in levels of atmospheric methane

The rise of fracking has led to a global spike in atmospheric methane, according to new research.

A paper published in the journal Biogeosciences, based on research conducted at Cornell University, suggests that increasing methane concentrations in the Earth’s atmosphere are due to shale oil and gas operations.

The work suggests that this methane has less carbon-13 relative to carbon-12 than methane from conventional natural gas and other fossil fuels such as coal.

In effect, this ratio acts as a signature for methane produced by high-volume hydraulic fracturing, or fracking, as it’s known. In the US and Canada, about two-thirds of all new gas production over the last decade has been shale gas, but in other countries it remains controversial.

While atmospheric methane concentrations have been rising since 2008, the carbon composition of the methane has also changed. Methane from biological sources such as cows and wetlands have a low carbon-13 content - compared to methane from most fossil fuels. Previous studies erroneously concluded that biological sources are the cause of the rising methane, says Robert Howarth, the paper’s lead author and professor of ecology at Cornell University. 

Methane is a greenhouse gas, but it behaves quite differently to carbon dioxide in the atmosphere, with the climate reaction more quickly to changes in methane levels. 

"Reducing methane now can provide an instant way to slow global warming and meet the United Nations' target of keeping the planet well below a 2-degree Celsius average rise," Howarth says. 

Levels of atmospheric methane levels had plateaued in the first decade of the milllennium after a rise in the last two decades of the 20th century, but then increased dramatically between 2008 and 2014.

"This recent increase in methane is massive," Howarth says. "It's globally significant. It's contributed to some of the increase in global warming we've seen and shale gas is a major player."

"If we can stop pouring methane into the atmosphere, it will dissipate," he said. "It goes away pretty quickly, compared to carbon dioxide. It's the low-hanging fruit to slow global warming."