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Greenhouse gas emissions could be much lower than many scientists reported in recent years, even as the production of natural gas in the U.S. continues to grow amid a boom in production in southeast New Mexico and West Texas’ Permian Basin.
A study published this month by the National Oceanic and Atmospheric Administration (NOAA) – an arm of the U.S. Department of Commerce – pointed to a 46 percent increase in natural gas production since 2006 but that methane emissions saw “no significant” increase during that same time period, and only slight growth from oil and gas.
The finding was based on methane measurements collected during 10 yeas from 20 long-term sampling sites around the country included in NOAA’s Global Greenhouse Gas Reference Network.
Air samples were gathered from aircraft at 11 sites and nine tall towers in the Network.
This allowed scientists to analyze concentrations at close to the ground where emissions occur and higher in the atmosphere to understand “their fate,” read the report.
“The sampling sites were established in locations where sampling would capture well-mixed air masses and avoid samples dominated by local sources,” the report read.
The study did not did not quantify methane emissions, oil and gas or not, but worked to identify if emissions were increasing by observing enhancements in atmospheric concentration of the gas – a primary ingredient in natural gas.
“We analyzed a decade’s worth of data and while we do find some increase in methane downwind of oil and gas activity, we do not find a statistically significant trend in the U.S. for total methane emissions,” said Xin Lan, lead author of the study and a scientist with the Cooperative Institute for Research in Environmental Services at the University of Colorado at Boulder.
Methane emissions from oil and gas activity increased about 3.4 percent per year, read the study, up to 10 times lower than recent studies.
That’s because many studies derived their trends from measuring levels of ethane, another petroleum hydrocarbon, the study read.
Ethane is emitted through oil and gas production and is also used as a “tracer” for oil and gas activity, read the study, as it is not generated biologically.
Meanwhile, overall methane concentrations in the air appeared to be increasing at the same rate as the “global background,” which means there was no “statistically significant” increase in the U.S.
“What this means is if you want to track methane, you have to measure methane,” Lan said.
While methane is a component of natural gas, it is also generated biologically such as by decaying wetlands or ruminant digestion when cows digest food through fermentation in a specialized stomach.
Methane is 28 times for potent than carbon dioxide in trapping atmospheric heat over 100 years, and exerts the second-largest influence on global warming behind CO2, the study read.
“By measuring ethane, which is not generated by biologic processes, scientists had hoped to produce an accurate estimate of petroleum-derived methane emissions,” read the study.
But past studies assumed the ratio of ethane to methane in natural gas produced in oil and gas regions was constant, as it actually increased and led to “overestimations” of oil and gas emissions.
Globally, methane levels were “nearly stable” from 1999 to 2006, read the study, but since have increased significantly, but NOAA data suggested the growth was “dominated” by biogenic emissions.
Lan said three of five the sampling sites located downwind from oil and gas operations did show some increases in methane, ethane and propane but could have been caused by different activity levels and the makeup of underlying oil and gas resources.
“With 20 sites across the country, we can make enough measurements to evaluate aggregate emissions at large regional scales,” she said. “If we had more sampling sites, we would be able to provide more specificity about methane sources in regions dominated by agriculture and oil and gas.”
‘Sour wind’ in Texas?
Despite the NOAA report on methane emissions, air pollution in the Permian could be on the rise.
A May 9 report from the Environmental Integrity Project (EIP – a Washington D.C.-based environmental non-profit organization – pointed to increases in sulfur dioxide (SO2) levels that could bring state and federal action.
SO2 exposure can harm human respiratory systems after short-or long-term exposure, per a report from the U.S. Environmental Protection Agency (EPA), while also damaging plant life and contributing to acid rain.
It can be released by oil and gas operations through the flaring of natural gas – a process often used when a well is first drilled to safely reduce gas pressure.
The EIP report pointed to one monitor for SO2 about 60 miles east of Odessa in Big Spring, Texas that reportedly showed levels of the gas up to 30 times higher than federal air quality standards.
“Industrial air pollution in West Texas requires immediate action from state and federal regulators, and first and foremost better air quality monitoring to help protect public health,” said Ilan Levin, Texas Director of EIP and lead author of the report.
“The growing number of oil and gas facilities are releasing vast amounts of sulfur dioxide and hydrogen sulfide, and either Texas or EPA needs to crack down on this hazard.”
The study used self-reported pollution data from the oil and gas industry in an around Ector County, Texas which contains Odessa – a total population of 156,000.
From 2014 to 2017, the EIP reported 35 percent of the county had SO2 levels higher than the EPA’s National Ambient Air Quality Standard, which should cause State or federal intervention, the report read.
The EIP called on the State of Texas to increase monitoring for SO2, as only one of three air monitoring stations in the Odessa-Midland region measure for SO2.
The organization also called on the EPA to conduct its own investigation into federal air quality standards and for the Texas Commissions on Environmental Quality to “more vigorously” enforce state permitting rules and crack down on pollution in the Permian.
“Texans deserve to be informed about the harmful pollutants the oil and gas industry is pumping into the air we breathe,” said Neil Carman, clean air program director for the Sierra Club’s Lone Star Chapter. “It’s long past time for state and federal leaders to act to protect our communities from dangerous air pollution.”