Four Corners Methane Study Ignores Established Data

Recently, researchers from NASA and the University of Michigan released a report asserting the presence of a methane “hot spot” in the four corners region – an area in the San Juan Basin where the borders of Arizona, New Mexico, Colorado, and Utah meet. The researchers concluded that the hot spot is “likely from established gas, coal, and coalbed methane mining and processing.”

Before we go any further, it’s important to point out that the methane readings are not due to hydraulic fracturing. The report states:

“We quantitatively use the observed CH4 enhancement to demonstrate that emissions associated with established fossil fuel extraction activities (not associated with recent high-volume hydraulic fracturing activities) are significantly underestimated over large scales.” (p. 1; emphasis added)

Instead, the study argues that the high reading is likely due to gas processing and compression facilities. The press release for the study puts that in plain terms:

“The study’s lead author, Eric Kort of the University of Michigan, Ann Arbor, noted the study period predates the widespread use of hydraulic fracturing, known as fracking, near the hot spot. This indicates the methane emissions should not be attributed to fracking but instead to leaks in natural gas production and processing equipment in New Mexico’s San Juan Basin, which is the most active coalbed methane production area in the country.” (emphasis added)

But there are some major problems with that argument. Let’s have a look.

Problem #1: Ignores well-known phenomenon of natural methane seepage in the San Juan Basin

The San Juan Basin is well-known as a large area of natural seepage – when methane emissions are naturally occurring and not the result of energy development.  According to a 1999 report from the U.S. Bureau of Land Management (BLM), “Historically documented naturally occurring gas seeps throughout the San Juan Basin existed prior to oil and gas drilling operations.”  BLM continues,

Shallow water wells penetrating Fruitland and Menefee coalbeds around the Basin rim have historically produced methane gas.  Especially notable in La Plata County, Colorado, are seeps at the northern and western rim of the San Juan Basin. Known gas seeps include the Carbon Junction area where the Animas River crosses the Fruitland Formation.  At this location methane and hydrogen sulfide seeps were commonly recognized as early as the 1930’s (Amoco, 1996).  Local residents noted as early as 1920 that a ‘rotten egg smell’ is being emitted from the Carbon Junction Area” (Whitton, personal communication, 1996).  Another well-known site of historic gas seepage is a topographic low in the Hogback Monocline between Valencia Canyon and Iron Springs Canyon on the western rim of the San Juan Basin.  Historically emitting odors of ‘rotten egg gas’ (hydrogen sulfide), this pass through the hogback was known by old-timers as ‘stink hill.’  Other areas of seepage existed at the northeastern edge of the San Juan Basin rim.  Ranchers ignited escaping natural gas from water faucets, holes punched in iced-over streams, or known soil seeps in entertaining pyrotechnic displays impressing new-comers or merely celebrating the Christmas Season (Halverson, 1994; Hocker, 1994).”  (p. 14-15)

Speaking of hot spots, the BLM goes on to explain,

“Scoria, cinders, clinker beds, and ash remnants bear testimony to pre-historic fires.  North of the Colorado-New Mexico State line lie the Cinder Buttes, distinguished by distinctly reddish oxidized and heat-altered clinker.  The name attests to the fact that subterranean fires consumed shallow coalbeds.  Recent mapping of the Fruitland outcrop along the Basin rim documents numerous sites where theses ash and clinker deposits grade into recognizable coal seams.  It is a matter of clear geologic record that coal fires have been an integral part of the geologic history of near-surface coal exposures in the Furitland Formation.  Spontaneous combustion can be spawned by fluctuation of water levels within coalbeds.” (p. 16-17; emphasis added)

Nowhere in the report do these researchers address these well-established facts. Instead, they attribute the methane entirely to natural gas systems.

Problem #2: Does not account for why the Four Corners is the only “hot spot”

The researchers admit that even in the areas across the country where their readings of methane emissions are more elevated, those areas still have more than 50 percent less methane than the Four Corners area.  From the report:

“The largest local enhancement over this time frame is located over the Four Corners region of the U.S. (where Arizona, New Mexico, Colorado, and Utah all meet, Figure 1b). Other regions show elevated CH4 levels as well: notably the Texas/Oklahoma region and central California. These elevated levels are likely associated with anthropogenic emissions from oil, gas, ruminants, and agriculture, as noted in recent focused studies on these regions [Katzenstein et al., 2003; Kort et al., 2008; Miller et al., 2013]. Methane signals in these regions are weaker (~50% of Four Corners) and less persistent (not present in all seasons and years) than those observed at Four Corners; thus, it is more difficult to reliably constrain source strength and perform attribution.” (p. 2; emphasis added)

This leads to an interesting question: if the hot spot in 2009 were due to natural gas processing equipment, as the researchers purport, why are other top natural gas producing areas not showing high methane emissions?  Here’s the primary chart from the report:


Compare this chart to data from the Energy Information Administration (EIA) below.  According to EIA, the top ten natural gas producing areas in 2009, aside from the Four Corners region, were in parts of Wyoming, Oklahoma, Colorado, Utah, Arkansas, Texas and Louisiana — yet none of those areas had emissions that were anywhere close to approaching a “hot spot.”  In fact, several of these top natural gas producing areas – northern Louisiana and Arkansas, for instance – show exceedingly low methane emissions in 2009. Just a few years ago, the Haynesville Shale in northern Louisiana was actually one of the most significant gas fields in the United States: in 2009, a Forbes article described it as “the largest natural gas field in the continental U.S.”

Yet higher methane emissions can be seen across Nebraska and Iowa, where little-to-no natural gas production was happening (the methane source is likely livestock, which actually accounts for more methane emissions than natural gas systems, according to the EPA).

2009 proved reserves

Instead of making an effort to account for these large discrepancies in data, the researchers settle with making vague comments about how the methane emissions across the middle of the country “are likely associated with anthropogenic emissions from oil, gas, ruminants, and agriculture.” But how does one distinguish between these?

Problem #3: Does not account for venting during coal production

While the researchers go to great lengths to argue that natural gas production and processing equipment are the cause of the methane, what they didn’t explain is that the San Juan Basin is also a major coal producing area.  In 2008, there were five active coal mines in New Mexico located in the San Juan Basin, which produced 25.6 million tons of coal.

Importantly, the venting of methane is actually required to develop coal safely. This process is tightly regulated and well-understood.  According to the Environmental Protection Agency (EPA),

“To ensure mine safety, fresh air is circulated through underground coal mines using ventilation systems to dilute in-mine concentrations of methane to levels well below explosive levels. Mine safety authorities in each country regulate these concentrations. Typically, methane concentrations in ventilation air range from 0.1 percent to 1.0 percent.

Ventilation air methane (also known as VAM) refers to the very dilute methane that is released from underground mine ventilation shafts. VAM represents over half of all coal mining emissions in the United States and worldwide. With few exceptions, it is simply released to the atmosphere.”

Meanwhile, as U.S. natural gas production has skyrocketed in recent years, methane emissions have actually fallen considerably. According to the Environmental Protection Agency’s (EPA) latest Greenhouse Gas Reporting Program,

“{In 2013} reported methane emissions from petroleum and natural gas systems sector have decreased by 12 percent since 2011, with the largest reductions coming from hydraulically fractured natural gas wells, which have decreased by 73 percent during that period. EPA expects to see further emission reductions as the agency’s 2012 standards for the oil and gas industry become fully implemented.”

This is in line with EPA’s previous Greenhouse Gas Inventory, which found that 2011 methane emissions from natural gas systems had fallen 16.9 percent from 1990 levels, with field production emissions falling more than 40 percent since 2006. The reason, according to the agency, was largely “due to increased voluntary reductions” by oil and gas producers.  These voluntary measures include the increased adoption of what’s known as a “green completions,” where the methane is captured at the well head.  As Energy Secretary Ernest Moniz recently explained, “More than half I believe now of the frack jobs are so-called green completions where the methane is captured and is for economic benefit.”

Meanwhile, the Intergovernmental Panel on Climate Change (IPCC) has also credited hydraulic fracturing and the increased use of natural gas with dramatic decreases in greenhouse gas emissions, bringing our emissions to a twenty year low last year.

Although identifying methane “leaks” and reducing them are worthy goals, it’s important that we make our decisions based upon the best data. This latest study on the Four Corners region makes some interesting observations, but the insistence on blaming natural gas activity – while ignoring or dismissing information that suggests otherwise – is a substantial error. Convenient explanations may make for great headlines, but they don’t provide much in the way of better understanding environmental impacts.


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