Fracking drives methane surge

Abstract

Since 2008, atmospheric methane concentrations have surged. This change has previously been attributed to an increase in biogenic methane sources, particularly agriculture. But new research suggests this may not be the case (Biogeosci. 2019, DOI: 10.5194/bg-16-3033-2019). Biogenic sources of methane have a characteristic isotopic signature that contains less carbon-13 than fossil fuels. As atmospheric methane’s signature has been becoming more depleted in 13C since 2008, researchers have attributed the rise in emissions to biogenic sources. However, previous researchers assumed that all fossil fuels have the same carbon isotope ratios. Robert Howarth, a Earth systems scientist at Cornell University, wondered if different fossil fuel sources might also have different isotopic signatures. He found that shale gas is depleted in 13C compared with traditional natural gas sources, which suggests that fracking, not agriculture, could be responsible for methane’s surge in the past decade. His analysis suggests th...