The boom in the US shale gas and oil may have ignited a significant global spike in methane emissions blamed for accelerating the pace of the climate crisis, according to research.
Scientists at Cornell University have found the “chemical fingerprints” of the rising global methane levels point to shale oil and shale gas as the probable source.
Methane, levels of which have been increasing sharply since 2008, is a potent greenhouse gas that heats the atmosphere quicker than carbon dioxide.
Researchers at Cornell said the carbon composition of atmospheric methane, or the “weight” of carbon within each methane molecule, was changing too.
Robert Howarth, the author of the paper published in the journal Biogeosciences, said the proportion of methane with a “carbon signature” linked to traditional fossil fuels was falling relative to the rise of methane with a slightly different carbon make-up.
Researchers had previously assumed the “non-traditional” methane was from biological sources such as cows and wetlands, but the latest research suggests unconventional oil and gas from fracking may be playing a significant part.
The theory would support a correlation in the rise of methane in the atmosphere and the boom in fracking across the US over the last decade.
“This recent increase in methane is massive,” Howarth said. “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.”
However, UK academics have said the jury is still out because there remained “significant uncertainty” about the theory, which has not been conclusively proven.
The claim is “highly contentious in the academic community and further work is needed to constrain uncertainty before conclusions such as this can be robustly backed up”, said Prof Grant Allen, from the Centre for Atmospheric Science at the University of Manchester.
“However, this paper makes a very important point,” he said. “Controlling emissions from fracking, and fossil fuels in general, represents a potential policy quick fix to stemming the rise of methane still further.”
Howarth said his report showed that if humans stopped emitting large quantities of methane into the atmosphere, it would dissipate. “It goes away pretty quickly, compared to carbon dioxide. It’s the low-hanging fruit to slow global warming,” he said.