Research & Commentary: Study Says Methane Emissions from Oil and Natural Gas Production Are Significantly Lower than Previous Estimates

Published May 29, 2019

A new study published in the peer-reviewed journal Geophysical Research Letters finds methane (CH4) emissions coming from oil and natural gas production over the past decade are “an order of magnitude lower” than what has been reported by previous studies. The study was authored by researchers at the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado.

“Based on long-term and well-calibrated measurements,” the study concludes, “we find that (i) there is no large increase of total methane emissions in the United States in the past decade; (ii) there is a modest increase in oil and gas methane emissions, but this increase is much lower than some previous studies suggest; and (iii) the assumption of a time-constant relationship between methane and ethane emissions has resulted in major overestimation of an oil and gas emissions trend in some previous studies.”

The researchers also conclude errors in previous estimates come from using ethane (C2H6) and propane (C3H8) measurements to measure methane. “Although C2H6 and C3H8 are appropriate indicative tracers for [oil and natural gas] emissions,” the authors note, “[oil and natural gas] CH4 trends cannot be accurately estimated from C2H6 and C3H8. Thus, any conclusion of a large fossil CH4 increase in the past decade from studies that have used the constant [overall emission reduction efficiency] assumption is unreliable.”

The results of their study are bolstered by the U.S. Environmental Protection Agency’s (EPA) 2018 Greenhouse Gas Inventory (GHGI), released in April 2019, which revealed total greenhouse gas (GHG) emissions in the United States decreased by 35.6 million metric tons of CO2 equivalent, or 0.5 percent from 2016 to 2017. Indeed, U.S. GHG emissions are now at their lowest levels since 1992 and only 1.3 percent higher than their 1990 levels. Since 2005, GHG emissions are down 12 percent. The GHGI also goes on to note methane emissions have declined by a total of 15.8 percent since 1990, and those emissions from petroleum and natural gas systems have decreased by 10.5 percent and 14.2 percent, respectively, over the same period. Over this same period, oil production in the United States has increased by 80 percent and natural gas production has increased by 51 percent, according to the Energy Information Administration. This production increase has primarily been due to the hydraulic fracturing “fracking”) revolution.

Overall, air pollution is becoming less and less of a problem over time. A Texas Public Policy Foundation report notes in the United States from 1970 to 2017, “the aggregate emissions of the six criteria pollutants identified in the Clean Air Act have declined by 73 percent. This improvement has occurred alongside a 262 percent increase in Gross Domestic Product (GDP), a 189 percent increase in vehicle miles traveled, and rising population and energy consumption. These achievements should be celebrated as a public policy success story, but instead the prevailing narrative among political and environmental leaders is one of environmental decline that can only be reversed with a more stringent regulatory approach.”

The report further stresses, “In contrast to this doomsday narrative, consider the data. Since 1990, the ambient concentrations of these six pollutants—measures of what we inhale with each breath—have decreased by an average of 64 percent. Ambient concentrations of lead, sulfur dioxide, and carbon monoxide have declined by 98 percent, 88 percent, and 77 percent, respectively, since 1990. Airborne emissions of mercury and mercury compounds in the U.S. have declined by 74 percent since 2000. Ambient concentrations of benzene, a well-known carcinogen and the most widespread hazardous pollutant, declined by more than 66 percent from 1994 to 2013.

“What made these achievements possible were advances in emissions control technologies and the economic prosperity that enabled the widespread implementation of those technologies, as well as the means to monitor their effect on air quality,” the report concludes.

Air quality in the United States has reached a point where new regulations or tighter standards are no longer necessary. Rather than wasting billions of taxpayer dollars chasing away the last remaining molecules of a possible pollutant, lawmakers should refrain from passing new legislation and allow air quality to improve even further as technological advancements develop.

Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017
EPA’s Greenhouse Gas Inventory provides a broad overview of all U.S. greenhouse gas emissions sources and sinks, introduces key concepts, and discusses the primary drivers for changes in greenhouse gas emissions. The 2018 version finds greenhouse gas emissions decreased by 0.5 percent from 2016 to 2017 and are now just 1.3 percent above 1990 levels.

The U.S. Leads the World in Clean Air: The Case for Environmental Optimism
This paper from the Texas Public Policy Foundation examines how the United States achieved robust economic growth while dramatically reducing emissions of air pollutants. The paper states that these achievements should be celebrated as a public policy success story, but instead the prevailing narrative among political and environmental leaders is one of environmental decline that can only be reversed with a more stringent regulatory approach. Instead, the paper urges for the data to be considered and applied to the narrative.

The Social Benefits of Fossil Fuels
This Heartland Policy Brief by Joseph Bast and Peter Ferrara documents the many benefits from the historic and still ongoing use of fossil fuels. Fossil fuels are lifting billions of people out of poverty, reducing all the negative effects of poverty on human health, and vastly improving human well-being and safety by powering labor-saving and life-protecting technologies, such as air conditioning, modern medicine, and cars and trucks. They are dramatically increasing the quantity of food humans produce and improving the reliability of the food supply, directly benefiting human health. Further, fossil fuel emissions are possibly contributing to a “Greening of the Earth,” benefiting all the plants and wildlife on the planet.

Climate Change Reconsidered II: Fossil Fuels – Summary for Policymakers—summary-for-policymakers
In this fifth volume of the Climate Change Reconsidered series, 117 scientists, economists, and other experts assess the costs and benefits of the use of fossil fuels by reviewing scientific and economic literature on organic chemistry, climate science, public health, economic history, human security, and theoretical studies based on integrated assessment models (IAMs) and cost-benefit analysis (CBA).

Debunking Four Persistent Myths about Hydraulic Fracturing
This Heartland Institute Policy Brief by Policy Analyst Timothy Benson and former Heartland communications intern Linnea Lueken outlines the basic elements of the fracking process and then refutes the four most widespread fracking myths, providing lawmakers and the public with the research and data they need to make informed decisions about hydraulic fracturing.


Nothing in this Research & Commentary is intended to influence the passage of legislation, and it does not necessarily represent the views of The Heartland Institute. For further information on this subject, visit Environment & Climate News, The Heartland Institute’s website, and PolicyBot, Heartland’s free online research database.

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