State Impact: Atmospheric Methane Study
A new study of atmospheric methane in the United States suggests much higher levels than previously thought. StateImpact’s Joe Wertz reports the new data raises questions about natural gas production in Oklahoma and neighboring states, where emission estimates have more than doubled.
Each year, the U.S. Environmental Protection Agency issues a report that tracks the country’s greenhouse gas emissions. In the 2013 update released in April, the EPA dramatically lowered its estimate of methane from natural gas production. Methane emissions looked like they were going down, while natural gas production from hydraulic fracturing was booming. The energy industry welcomed the news, but new research casts doubt on the EPA’s declining methane numbers. A study co-authored by more than a dozen scientists and published last week in the Proceedings of the National Academy of Sciences, shows the opposite: Methane emissions have increased by more than 50 percent nationally. And in Oklahoma, Kansas and Texas — methane emissions are more than twice as high. The study’s lead author, Harvard PhD student Scot Miller, says that means a quarter of all of the country’s methane could be coming from just three states.
“That type of information really suggests to us that the oil and gas industry are key players,” Miller says.
Methane can leak from natural gas wells, pipelines and other types of production equipment. Miller says there’s another source of methane leaks: Cows leak methane, too. Miller says livestock is likely responsible for much of the country’s gas problem, but he says the data show that the methane emissions in Oklahoma, Texas and Kansas are likely natural gas-related. How does Miller know? And why are his numbers at odds with those generated by the EPA and EDGAR, the global database of greenhouse emissions?
“They try to count up the total number of cows in the United States, the total number of landfills, wastewater treatment plants, oil and gas facilities,” Miller explains. Then they multiply those numbers by an expected amount of methane each might typically produce … which is what Miller says is “basically an accounting measure.”
But atmospheric methane molecules were actually counted in Miller’s study. The data came from the Department of Energy and NOAA, the federal atmospheric and weather research agency, which took atmospheric samples during thousands of aircraft flights and from sensors placed atop towers that can be as tall as the Empire State Building. And in the air above Oklahoma and its neighboring states, the sensors also picked up propane.
“Propane is a byproduct of the fossil fuel industries, but it’s not produced by cows, it’s not produced by wetlands, it’s not produced by most other methane sources,” Miller says.
The methane sample data is from 2007 and 2008, which is the most recent available. But Oklahoma’s high methane emissions correspond with a gushing natural gas production, a time when the state had more rigs drilling for gas since the 1980s oil boom. The state agency charged with monitoring and regulating air emissions, Oklahoma’s Department of Environmental Quality, denied StateImpact an interview about how the new methane data might affect state pollution policy. The EPA declined an interview, too, and sent a boilerplate statement saying it welcomed any new data on greenhouse gas emissions. Miller, the study author, says that going forward, collaboration is the only way accurately assess the impact of greenhouse gasses.
Miller says another study using more recent methane samples is already underway.
StateImpact is a collaboration of Oklahoma public media stations and NPR.