Natural gas is often touted as what is called a “bridge fuel,” an energy source with a substantially lower carbon footprint than coal or oil that could help wean us off these higher-polluting energy sources, while still bringing the benefits and trappings of fossil fuels. It might be true that natural gas emits less carbon dioxide than other fossil fuels, but this ignores the fact that in the U.S. over 40% of natural gas is now derived from fracking, and that its extraction releases the more potent greenhouse gas methane.
Taking all this into account, it now seems that the Environmental Protection Agency (EPA) has been grossly miscalculating methane emissions within the United States. A new study has shown that while the EPA has been claiming that the nation’s greenhouse gas emissions have been decreasing, this might not actually be the case when all the extra methane released by shale gas extraction is taken into account. While methane hangs around in the atmosphere for a shorter period of time compared with carbon dioxide, its impact on climate change is roughly 25 times greater over a hundred-year period.
“The EPA has seriously underestimated the importance of methane emissions in general – and from shale gas in particular,” says Cornell’s Robert Howarth, who authored the paper published in the journal Energy Science and Engineering. “As a result, the federal government has been stating that total greenhouse gas emissions from energy use in the U.S. have been steadily declining since 2008 – which they attribute to exchanging shale gas for coal for electricity generation.”
According to the study, the EPA’s claim that greenhouse gas emissions for the United States in 2013 were around a massive 6 pentagrams (6 billion tons) was probably a vast underestimation. Using more accurate and up-to-date data on how much methane shale gas wells emit over their entire lifetime, the study found it to be actually somewhere around 9.5 pentagrams being emitted into the atmosphere. This new data could cast doubt on the notion of natural gas – specifically that which is derived from fracking – being a cleaner, greener bridge fuel.
This isn’t the first time the EPA has been caught out miscalculating methane emissions this year either. It turned out that the amount of trash thrown away by Americans was double what the EPA estimated, and with landfill sites thought to comprise up to 18% of all methane emissions in the U.S., they likely massively underestimated their greenhouse gas emissions from this source too.