Fracking boom ‘dramatically’ boosts methane emissions

Fracking is a technique which involves injecting highly pressurised liquid into drilled holes in order to fracture deep-rock formations and allow for the release of natural gas and other substances through the rock, such as the release of shale gas from shale rock.

While fracking has been adopted in many countries over the past 20 years, it is highly controversial on account of its environmental impact, which includes local pollution and triggering of earthquakes.

The Cornell University study looked at the ‘chemical fingerprint’ of methane in the atmosphere by examining the mass of the carbon atom at the core of the gas molecule. The study's conclusion was that approximately a third of methane released in the past decade could be traced back to fracking for shale gas. Methane from fossil fuels, such as from natural gas, contains higher concentrations of the significantly heavier carbon-13 isotope, while methane emitted from biological sources contains less of the heavy isotope and more of the lighter carbon-12.

Methane from fossil fuels has probably exceeded emissions from biological sources in the past decade, the researchers concluded, with shale gas accounting for more than half of the total methane released from fossil fuels.

“The commercialisation of shale gas and oil in the 21^st century has dramatically increased global methane emissions,” the study authors wrote.

Methane, an important greenhouse gas, is formed naturally inside the Earth. However, methane levels have risen rapidly in recent years, in part due to biological sources such as livestock and rice paddies. For example, the average cow releases between 70 and 120kg of methane every year.

Methane levels have risen consistently since 2008 (with sharp increases in atmospheric methane reported between 2015 and 2019), threatening efforts to reduce greenhouse gas emissions and minimise global average temperature rises in accordance with the Paris Agreement. While methane does not have as much of a long-term impact as carbon dioxide on Earth’s climate, it is still a particularly potent gas, causing rapid changes to the climate.

The study, published in Biogeosciences, repeats warnings that rising methane levels undermine efforts to meet greenhouse gas reduction targets and curb the most devastating impacts of climate change.

The UK’s independent Committee on Climate Change has warned that emissions from the shale gas industry must be restricted via close monitoring, regulation and action to address methane leaks. However, the Cornell researchers suggest that the best strategy is to “move as quickly as possible away from natural gas”, which should not be considered a “bridge fuel” between heavily polluting fossil fuels and carbon neutral energy sources.

Cornell Professor Robert Howarth, who authored the paper, commented that: “[Fracking] is 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. It goes away pretty quickly, compared to carbon dioxide. It’s the low-hanging fruit to slow global warming.”