In 2011, Ingraffea and two other Cornell researchers published a highly discussed scientific study in the journal Climatic Change, arguing that between 3.6 and 7.9 percent of methane gas from shale drilling operations actually escapes into the atmosphere, where it contributes to global warming. If true, then considering the unique atmospheric potency of methane—”methane is about 80 to 90 times…more potent as a greenhouse gas than carbon dioxide” over a two-to-three-decade time period, says Ingraffea—the implications could be dramatic. Natural gas could swing from being a net climate benefit (because it burns cleaner than oil or coal) to a climate harm, because of all the escaping methane.
Four Fayetteville shale well heads in Arkansas. Critics like Ingraffea say significant amounts of fugitive methane gas are escaping from fracking operations around the country (though not necessarily the one above). Bill Cunningham, US Geological Survey.
Granted, it all depends on the leak rate from natural gas operations, across all the myriad stages of the process, from the initial release of the gas from the Earth all the way through to its transportation. And that’s where the debate lies. “Every single measurement has concluded that the percentage of methane leaking into the atmosphere from oil and gas operations is far greater than two and a half percent,” says Ingraffea. “I think the best estimate right now is somewhere around 5 percent”—an amount, he says, that would be more than big enough to doom the idea of natural gas as a “bridge fuel” to a clean energy future.
Ingraffea isn’t the only researcher suggesting that methane leakage is troublingly high. In a 2013 study published in the prestigious Proceedings of the National Academy of Sciences, a team of researchers from both US universities and national labs found that the EPA is currently underestimating methane emissions from the energy industry (including both conventional and shale gas drilling). However, in another paper in Science earlier this year (covered here by Mother Jones), researchers again faulted EPA’s methane measurements, but nonetheless concluded that natural gas can still contribute to a cleaner future if methane emissions are policed adequately. (The UN’s Intergovernmental Panel on Climate Change has reached a similar conclusion.)