Methane is one of the more potent greenhouse gases for global warming. The concentration of methane in the atmosphere stabilized from about 1999 to 2007, but since 2007 began rising again. A recent study suggests that the more than 30% increase in U.S. methane emissions over the 2002–2014 period could account for 30–60% of the global growth of atmospheric methane seen in the past decade.
When Prime Minister Justin Trudeau visited President Barack Obama in March, one of the topics that was discussed was joint action on climate change. Specifically, Canada and the United States committed to new actions to reduce methane pollution from the oil and natural gas sector.
In March, 2014 the U.S. Administration issued Strategy to Reduce Methane Emissions, which outlined steps to cut methane emissions. In the summer of 2015 the U.S. Environmental Protection Agency (EPA) proposed standards to directly address methane from new and modified sources in the oil and gas sector with the goal of reducing methane emissions from the oil and gas sector by 40 to 45 percent below 2012 levels by 2025. But studies from the Environmental Defense Fund (EDF) and others have provided significant new data on methane emitted by existing operations in the oil and gas sector that show that "methane emissions are substantially higher than we previously understood" in the words of Gina McCarthy, EPA Administrator.
In 2012, the EDF initiated a series of 16 independent projects designed to find out how much and from where methane is escaping into the atmosphere across the entire natural gas supply chain: production; gathering lines and processing facilities; long-distance pipelines, storage, and local distribution; as well as some end users using natural gas, commercial trucks and refueling stations. This investigation involved nearly 100 research and industry experts.
Scientists collected data using aircraft and ground-based platforms in the Texas Barnett Shale. Using this data they estimated regional and facility-level methane emissions and found that regional methane emissions are 50 percent higher than estimates based on the Environmental Protection Agency’s Greenhouse Gas Inventory.
Methane emissions from local gas distribution systems were also investigated it was and found that methane emissions from local natural gas distribution systems are significant. The EDF and Google Earth Outreach released interactive maps that show methane leaking from pipelines under city streets.
The Denver-Julesburg Flyover Study found that methane emissions were three times higher than estimates derived from EPA data.
A study assessed the spatial distribution of anthropogenic methane sources in the United States by combining comprehensive atmospheric methane observations, extensive spatial datasets, and a high-resolution atmospheric transport model. Based on the results of this analysis the authors concluded that the EPA underestimates methane emissions nationally by a factor of ∼1.5 and regionally by ∼4.9.
A recent study which analyzed GOSAT satellite and surface observations of atmospheric methane suggests that U.S. methane emissions have increased by more than 30% over the 2002–2014 period. This contrasts with EPA estimates which indicate that emissions remained flat over this period. The increase is largest in the central part of the country. The spatial pattern of the methane increase seen by satellite does not clearly identify the sources of the increase. The renewed growth in atmospheric methane between 2005 and 2010 is estimated to be due to an increase in global methane emissions of 17–22 teragrams per year (Tg/yr). The new results suggest that increasing U.S. anthropogenic methane emissions could account for up to 30–60% of this global increase. The authors state that a better understanding of U.S. anthropogenic methane emissions, particularly those from the livestock and oil and gas sectors, is needed. The U.S. EPA inventory gives only national totals, so identifying sectors responsible for the increase is difficult. A spatially resolved version of the U.S. EPA inventory is currently under development.
The EPA's next annual methane report is due to be published by April 15 and it will be interesting to see what the EPA is doing to address the significant difference between its estimates and the estimates from academic researchers.
The shale oil and gas sector in the U.S. has been largely unregulated. In 2005 Congress passed the Energy Policy Act of 2005, which was an omnibus energy bill that included the so-called "Halliburton loophole" which exempted hydraulic fracturing from protections under the Clean Air Act, Clean Water Act, Safe Drinking Water Act, and CERCLA, which means that fracking has not been regulated at the federal level.
Since Prime Minister Trudeau's visit to President Obama the EPA has initiated a formal process to require companies operating existing oil and gas sources to provide information to assist in the development of comprehensive regulations to reduce methane emissions. The EPA is issuing an Information Collection Request (ICR) to gather information on existing sources of methane emissions, technologies to reduce those emissions and the costs of those technologies in the production, gathering, processing, and transmission and storage segments of the oil and gas sector. The goal is to take a closer look at regulating existing sources of methane emissions, in other words, to set more aggressive rules for reducing methane emissions from existing oil and gas facilities.
EPA intended to begin the ICR process In April by signing a draft information collection request that will be made available for public comment. The agency will revise that draft as necessary based on comment and send it to the Office of Management and Budget for additional review and input. Once the collection request is approved– which can include surveys and required emissions monitoring – it will go to industry, which is required to respond and attest that the information it provides is accurate. EPA’s goal is to receive the first phase of information later this year.
The EPA began the ICR process May 12, 2016.