A new study by researchers at the University of Michigan and the National Oceanic and Atmospheric Administration (NOAA) has produced some pretty alarmist headlines in recent days, none more foreboding than “Fracking in the U.S. causing global surge in dangerous gas.”
One might assume the “dangerous” gas in question is methane, considering it has become an obsession of opponents of shale development in recent years, based on the inaccurate notion that fugitive methane emissions are wiping out natural gas’ tremendous climate benefits.
But this study actually found such low levels of methane in the Bakken Shale region that they didn’t even bother to include estimates in their report. Which begs the question: How does a study finding low methane emissions still manage to generate hyperbolic headlines such as the one above? The answer: by focusing on ethane rather than methane, and selling them as equals.
Based on a series of measurements from flights in 2014 over North Dakota and Montana, the study claims the Bakken is solely responsible for two percent of the world’s atmospheric ethane emissions and is also single-handedly responsible for an upward spike in ethane emissions the past five years after more than a decade of declines. This entire hypothesis is based on a single 2009 report of increased ethane emissions from a remote mountaintop in Europe, by the way.
Setting aside for a moment how strange the latter notion seems, it is more important to understand that ethane emissions have largely been ignored by fracking opponents and the media up to this point for a reason. Here are three things you need to know about the study that (most) of the media missed, resulting in alarmist headlines popping up left and right.
Fact #1: Study finds low methane emissions; chooses to focus on ethane instead
The study states,
“… This study focused on assessing the atmospheric impact of oil and gas production in the Bakken with continuous measurements of methane, ethane, carbon dioxide, water vapor, carbon monoxide, ozone, black carbon, wind, pressure, and temperature as well as whole-air flask samples for analysis of dozens of other compounds.”
But you wouldn’t know what their methane measurements were by reading the actual study. Fortunately, the Washington Post asked the researchers about their methane data. From the Post:
“The new study suggests that the Bakken formation has accounted for much of the global increase in ethane emissions while emitting comparatively low levels of methane simultaneously.”
Venting and flaring of natural gas are thought to be the primary source of atmospheric ethane, and because of this, scientists have long assumed detection of significant atmospheric ethane correlates directly with high methane leakage. This study found the opposite to be true, however, as the authors concede in the report:
“Analyses that assume a temporally constant oil and gas production ethane: methane emission ratio lower than present in the Bakken, or other productive basins, will erroneously conclude a large fossil methane emissions increase since 2010…”
The Washington Post article expands on this major finding, which virtually every other media outlet ignored:
“They found that the ratio of ethane to methane produced by the Bakken was much higher than what has been observed in many other shale oil and gas fields in the United States — an observation that could have big implications for future methane assessments, which are important for climate scientists.
“In many oil and gas fields, methane is often the primary natural gas present — sometimes accounting for up to 90 percent or more of the gas that is released during extraction. Ethane often tends to be present in smaller proportions. In the Bakken, however, the researchers found that ethane accounted for nearly 50 percent of all the natural gas composition, while methane was closer to 20 percent.”
Though the report doesn’t list the methane emissions detected by its flights over the Bakken, the researchers estimated 250,000 tons of annual ethane emissions in the Bakken. So by the Washington Post’s math, annual methane emissions would be just 100,000 tons annually.
In other words, not only are methane emissions in the Bakken low, scientists can no longer assume that the detection of significant ethane emissions mean that high methane emissions are inevitable, as was assumed in a recent Karlsruhe Institute of Technology (KIT) study that claimed oil and gas production are driving up global methane emissions. The Washington Post article elaborated on this point further:
“And when ethane emissions began rising again, it was logical to assume that methane emissions — from oil and gas development, specifically — were also likely on the rise. But as the Bakken study points out, this is not necessarily the case….”
Christian Frankenberg, an environmental science and engineering professor at the California Institute of Technology and a researcher at NASA’s Jet Propulsion Laboratory, pointed out in the Washington Post article that making an incorrect assumption about the ratio of methane escaping compared to ethane: “might easily overestimate the methane increases in these areas.”
This conclusion further solidifies a separate NOAA and the National Institute of Water and Atmospheric Research (NIWAR) study that found the recent rise in global methane emissions is attributable to biogenic sources, rather than oil and gas. The lead author of the study, Hinrich Schaefer of NIWAR, said to Climatewire: “Currently increasing methane levels are caused not by fossil fuel production…”
Fact #2: Ethane is a non-issue for global warming and is not really on EPA’s radar
Many media reports on the study have played up the fact that ethane is a Volatile Organic Compound (VOC) that can contribute to ground-level ozone. Several stories have also pointed out that ozone ranks as the third-largest contributor to human-caused global warming after carbon dioxide and methane.
But these media reports fail to mention that ethane’s atmospheric lifespan is so short (roughly two months) that it isn’t considered a major factor in climate change. Ethane’s role in global warming is so insignificant, in fact, that ethane appears just five times in the 558-page 2016 EPA GHG Inventory, which describes non-methane VOCs as follows:
“Non-methane volatile organic compounds include substances such as propane, butane, and ethane. These compounds participate, along with NOx, in the formation of tropospheric ozone and other photochemical oxidants. NMVOCs are emitted primarily from transportation and industrial processes, as well as biomass burning and non-industrial consumption of organic solvents. Concentrations of NMVOCs tend to be both short-lived in the atmosphere and spatially variable.”
The study even notes that ethane acts as a greenhouse gas with a “modest global impact.”
A 1999 National Academies Press study on VOC emissions from vehicle exhaust further elaborates as to why ethane is not a significant contributor to tropospheric (ground-level) ozone:
“If one were to increase the total mass of VOC emissions in a city, such as Los Angeles, by 20% through additional emissions of ethane, ozone levels would increase slightly. However, if the same amount of propene were added instead, there would be a large increase in ozone. Why the big difference between the two, given that both are rather simple hydrocarbons? The primary cause of the difference is the differing rates at which these two species react in the atmosphere. Ethane has an atmospheric lifetime of weeks. Little of the ethane emitted in an urban area reacts within that area before it is transported away. Its contribution to ozone formation within the urban area is therefore very small.
“During the early years of ozone mitigation, it was recognized that there were some organics, for example ethane, that did not contribute significantly to smog formation on urban scales, whereas others, such as propene, did.”
Fact #3: North Dakota has good air quality
The EPA has the following to say regarding formation of ground-level ozone:
“… Ozone is likely to reach unhealthy levels on hot sunny days in urban environments. Ozone can also be transported long distances by wind. For this reason, even rural areas can experience high ozone levels.”
So if ethane levels were truly driving increased tropospheric ozone in the Bakken in North Dakota – a predominantly rural sate –one might surmise that the Bakken region would have significant air quality issues. But that simply has not been the case, and the authors of this study were unable to find any evidence of elevated ground-level ozone in the areas they monitored:
“Emissions of ethane, methane, and other VOCs from the Bakken have the potential to impact ozone formation on a variety of spatial scales. Local ozone enhancements observed during the Spring 2014 airborne study were relatively small due to low temperatures, large solar zenith angles, and generally high wind speeds. Initial GEOS-Chem modeling (for details see Supporting Text S1) suggests that in summer, when surface ozone production peaks, up to 4 ppb of additional ozone are produced in plumes downwind of the Bakken region due to emissions of alkanes with composition as in Table 1 (Figure 3, Supporting Movie S1).”
The latest State of the Air Report from the American Lung Association (ALA) found that six of the eight North Dakota counties with air quality monitors received “B” grades. ALA spokesman Robert Moffitt also notes in an article posted on publicnewsservice.org that North Dakota’s maintained good air quality “because natural gas and other alternatives…are just so much cheaper now.”
It’s a similar story across the entire country, for that matter. Nitrogen dioxide (NO2) – which when paired with sunlight and other things, can contribute to ground-level ozone formation and is linked to respiratory issues, according to EPA – has declined by 52 percent as natural gas use skyrocketed between 2005 and 2013.
Data from the EPA and the U.S. Energy Information Administration (EIA) also show a 60 percent decrease in PM 2.5 from 2005 to 2013. The same kind of dramatic decline can be seen in emissions of sulfur dioxide, which decreased by 68 percent from 2005 to 2013. According to EPA, sulfur dioxides (SOx, SO2 and SO3) can “penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease, such as emphysema and bronchitis, and can aggravate existing heart disease, leading to increased hospital admissions and premature death.” SO2 in particular is “of greatest concern” for health, according to EPA.
Most importantly, increased natural gas use has spearheaded a nine percent decline in CO2 emissions in the U.S. since 2005. Over that same period, U.S. natural gas production increased by 35 percent, and natural gas-fired electricity generation increased by 50 percent.
Natural gas became the No. 1 source of electrical generation in 2015. Not coincidentally, recent EIA data shows a two percent decline in carbon emission from electrical generation – the No. 1 source of GHG emissions – last year alone, which has helped the U.S. become the only major country to reduce CO2 emissions in recent years, as the following EID graphic illustrates:
Bottom line is that CO2 is greenhouse gas of most concern for climate change, which is why University of Oxford climate scientist Raymond Pierrehumbert recently told The Washington Post that reducing CO2 should be the major focus of efforts to combat climate change rather than methane:
“People are placing too much emphasis on methane. And really, people should prove that we can actually get the CO2 emissions down first, before worrying about whether we are doing enough to get methane emissions down.”
The same can be said regarding ethane.
We’re still scratching our heads as to why the researchers are blaming ethane emissions detected in Europe on the Bakken. But most importantly, they have (inadvertently) confirmed that methane emissions are very low in the nation’s most prolific oilfield. They’ve also noted what has long been suspected: That scientists could very well be overestimating methane emissions from oil and gas based on the mere detection of ethane.