Methane Leaks in New Mexico Far Exceed Current Estimates, Study Suggests

A new analysis of aerial data suggests that the oil and gas industry may be contributing more to climate change than was previously known.

Methane, a planet-warming gas many times more potent than carbon dioxide, is being released by oil and gas operations in New Mexico. The latest estimate from the Environmental Protection Agency was six times larger.

The authors of the study were surprised by the number, which was published in the journal Environmental Science and Technology.

We spent more than two years thinking of ways that we might be wrong and talking with other experts in the methane community.

He and Ms. Chen said they believed their results showed the necessity of surveying a large number of sites in order to accurately measure the environmental impact of oil and gas production.

The largest previous assessment of methane emissions from oil and gas in the United States was published in 2018, and reviewed studies covering about 1,000 well sites, a tiny fraction of the more than one million active wells in the country. More than 90 percent of all wells in the New Mexico portion of the Permian Basin were examined by the new study using aerial data.

The fact that operations and emissions vary over time was taken into account by the researchers. Methane can be released by wells both on purpose and through leaks from aging or faulty equipment.

The vast majority of methane leaks were accounted for by a small number of wells.

Robert Howarth, a professor of ecology and environmental biology at Cornell University who was not involved in the study, called it very carefully done. Methane emissions were calculated at 9.4 percent of gross gas production, dwarfing the EPA's estimate of 1.4 percent.

Natural gas is less expensive than coal in terms of carbon dioxide emissions, so policymakers have promoted it as a bridge that could do less damage to the climate while society works on it. Methane is a more potent greenhouse gas than carbon dioxide, but it doesn't last as long in the atmosphere.

A decade ago, an atmospheric chemist at the Environmental Defense Fund estimated that the break-even point was a 3.1 percent methane leak. Dr. Howarth believes that the threshold is closer to 2 percent.

Experts said that the 9.4 percent leakage rate in the new study is highly alarming and that the rate in the Permian Basin might not be comparable to rates elsewhere.

If this result is similar in other basins, that would eliminate the greenhouse gas emission savings of the coal-to-gas transition.

The study suggests that if the worst offenders change their practices, it is possible for the industry to operate more cleanly.

A rule was finalized last year by the New Mexico Oil Conservation Commission that banned the practice of releasing or burning off natural gas. The state's Environmental Improvement Board is considering a regulation that would require more frequent repairs to oil and gas infrastructure. The measure is designed to reduce emissions of volatile organic compounds, a group of chemicals that can have adverse health effects, but oil and gas sites that leak V.O.C.s tend to also leak methane.

The same methodology used to quantify methane emissions could be used to identify problem sites and target regulations.

Ms. Chen said that aerial technology found high methane emissions.