The Permian and the parks: the science of methane monitoring
National parks are “living laboratories” — science is part of their purpose. But parks have research value beyond the plants and animals, the rocks and rivers they protect.
Guadalupe Mountains and Carlsbad Caverns national parks are cases in point. They're helping scientists understand an unseen, but consequential phenomenon — the emission of methane, a potent greenhouse gas, from the Permian Basin oilfield.
Kenneth Davis and Zachary Barkley are atmospheric scientists at Penn State University.
“I sometimes refer to us as greenhouse gas auditors,” Davis said. “We come around to check the books, and in the case of methane emissions from gas basins, the books don't work too well.”
“And Carlsbad and Guadalupe play a key role in achieving that data set,” Barkley said.
When we think of climate-change drivers, carbon dioxide from burning fossil fuels comes to mind. Methane is different. The belching, and flatulence, of cows are one source. But leakage in natural-gas fields is the largest methane source. And the global-warming effects are acute, Davis said.
“Over a 20-year window, a gram of methane has something like 85 times the impact of a gram of CO2,” Davis said. “So for a short time window — 20 years being short for climate scientist — methane is much more impactful per unit-mass.”
Davis, Barkley and their colleagues first worked close to home, in the Northeast's Marcellus Shale gas play. In 2020, through a contract with the Environmental Defense Fund, they brought their expertise to the nation's largest oilfield — the Permian Basin.
Environmental regulators use a “bottom-up” approach to calculate methane emissions. They estimate leakage from every gas-field component, and multiply that by the number of components. The Penn State scientists take a different tack.
At towers on the perimeter of the Permian Basin — in Fort Stockton and Notrees, Texas, in Hobbs, New Mexico, and at Guadalupe and Carlsbad parks — they capture air. Then, with a technology called cavity ring-down spectroscopy, they measure the methane concentrations. The difference in concentrations on either side of the basin reveals how much methane is being released there.
The national-park sites provide a particularly useful baseline, because there are few methane sources west of the Guadalupes. In winter, when winds are westerly, the air here is virtually methane-free. When winds shift in summer, the park devices record an inundation of methane from the Permian.
And it paints a very different picture from the “bottom-up” approach. Federal regulators estimate methane leakage nationwide at one percent. But the atmospheric evidence indicates Permian Basin fields are losing three percent of natural gas in leakage.
And the research reveals other anomalies. For reasons the scientists don't fully understand, methane releases rise here in winter. That has implications for estimating emissions.
“Let's just imagine we do our bottom-up measurements for our inventories in the summer months,” Barkley said. “Well, suddenly your bottom-up inventory is going to be biased low, because as it turns out summer is lower. That would be an example of why this would matter in particular.”
New laws charge producers for excessive methane emissions. But the findings suggest regulators may need new techniques for calculating those emissions.
Methane itself does not pose a health risk. But its contribution to climate change is outsized. And controlling it could be easier than cutting down on fossil-fuel consumption. Producers, of course, would rather sell natural gas than lose it to leakage.
The research here is the only continuous monitoring of its kind in the world. But it could be a model for other oil-and-gas basins. And it's a reminder of the surprising contributions national parks can make to science.