Studies Confirm Low Methane Leakage Rates from Natural Gas Development

This week, the Environmental Protection Agency (EPA) rolled out its new regulations on methane emissions from oil and gas development. These rules come even as the industry has slashed emissions in recent years, all while natural gas production has skyrocketed.  As the Independent Petroleum Association of America (IPAA) pointed out, these costly proposals “could inflict more pain on the men and women who work in the oil and gas industry – at a time when market forces are already creating economic challenges.”

Of course, the reason the EPA wants to regulate methane is to mitigate climate change, since methane is a greenhouse gas. But based on the most recent peer-reviewed studies – many of them spearheaded by the Environmental Defense Fund (EDF) – and some of the best data we have available, the climate argument appears to fall apart. Indeed, the methane “leaks” from natural gas development are already well below the threshold (3.2 percent leakage rate) at which scientists believe natural gas may lose its greenhouse gas advantage:

Final Methane_Chart

Nevertheless, each time one of these studies has come out, instead of noting the low leakage rate, EDF has proclaimed that the data show emissions are “higher than previous estimates” and that new EPA regulations are absolutely necessary.  For instance, a spokesman for EDF recently claimed:

“Almost everywhere we look, we find emissions that are as high, or higher, than earlier estimates; that they are widespread and unpredictable in nature (and thus undercounted); and that they aren’t being fixed fast enough.”

The press has generally followed EDF’s lead, producing headlines like, “Methane leaks in Barnett Shale vastly higher than EPA estimates, study shows,” and “Methane emissions higher than federal estimates, study shows.”

But these reports are ignoring a critical fact. The most important information is not a comparison of one emission estimate with another. That tells us nothing about the overall environmental impact, and indeed only serves as a basis for us to compare one study to another. The practical implication is quite limited.

What’s far more important is the actual methane leakage rate, which is what determines whether natural gas is beneficial for the climate. That’s why we’re talking about methane, a greenhouse gas – climate change and how to address it, right?

The fact is, most if not all of the most recent studies on this subject have confirmed that methane leakage is not negating the climate benefits of natural gas. And as much as some environmental groups may want folks to be distracted into conversations about relative estimates between studies and inside baseball conversations about whether EPA needs to tweak some of its data assumptions, it would be unfortunate if we lost track of the bigger – and very positive – story of natural gas.


  1. Miguelito says:

    Yes, but each of the EDF’s studies examines parts of the natural gas system, from fracking, to production, to gathering, to processing, to transportation and distribution. They don’t measure the whole thing.

    Thus, examining them separately and saying “look how low gas emissions are!” isn’t very accurate, because each isn’t meant to be an estimate of the whole thing. Neither is lumping them together, because there’s probably some overlap.

    Chances are, what the EDF is finding is that the different parts they’re measuring have higher emissions than the respective parts the EPA has made estimates for.

    Altogether, gas is a far superior fuel to coal and will play a big role in reducing our GHG emissions, but it’s always best to look at studies in their context, especially when using them to criticize proposed EPA regulations.

    • Katie Brown, PhD says:

      Hi Miguelito, thanks so much for reading our blog and taking the time to comment.

      You’re right that each study focuses on a particular segment of the natural gas system, but what the researchers are doing is making an assessment of what the leakage rate is for one individual segment, then they use either EPA data or previous research as assumptions for the other sectors they didn’t study. They then combine those together to come up with a life cycle estimate.

      For instance, in EDF’s latest study, Marchese et al, the researchers look at gathering and processing operations and come up with these specific leakage rates from the study:
      “Total annual CH4 emissions of 2421 (+245/− 237) Gg were estimated for all U.S. gathering and processing operations, which represents a CH4 loss rate of 0.47% (±0.05%) when normalized by 2012 CH4 production.”

      They then compare this data to estimates by EPA, which, as the researchers state, “represents a total rate of CH4 loss of 1.3%.” From that benchmark, EDF’s Mark Brownstein explains the study’s findings this way:

      “Indeed, the newly identified emissions from gathering facilities would increase total emissions from the natural gas supply chain in EPA’s current Greenhouse Gas Inventory by approximately 25 percent if added to the tally.”

      A 25 percent increase to EPA’s 1.3 percent estimate equals 1.6 percent – a rate well below what most scientists say is advantageous for the climate.

      • AlexCKent says:

        Nuclear is still far better and does not increase mag 3-5 earthquakes 500x like fracking does

  2. Very informative piece of research and diplomatic commentary on the EPA and environmental groups’ spin on the message. I have long believed that climate change and man caused GHG emissions are interrelated and man can reverse or significantly slow down what appears to be a global warming phenomena with its ultimate catastrophic consequences. However a recent article in US News and World Report says that implementation of the EPA’s latest rules would only change global temperature by .015 degree C based on the EPA’s climate model. If that is true then there is an inconvenient truth here that needs exposure. And that is we are screwed no matter what we do, short of stopping the world. I realize the estimate relates to the US’s impact on global temperature so the net effect of the program would be quite small.

    That said I have followed the acidification of oceans issue for some fifteen years and witnessed a negative trend here in the northwest that is recent and serious and apparently atmospheric CO2 related. And since it is so recent, significantly reversing mankind’s C02 emission rates should have a direct significant favorable impact on the oceans. And my take on natural gas is it is the most practical and effective vehicle for reducing GHG’s during the transition to some less polluting and reliable energy source such as nuclear. Of course there are other atmospheric poisonous gasses from coal that suggest complete elimination of that source of pollution would be a good thing in any case.

    Still wrestling however with the issue of whether GHG emissions and global temperatures are that strongly correlated based on the US News article, but I am assuming that companies like Exxon don’t invest heavily in such things as carbon sequestration projects without evidence that the problem is real, and addressable.


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