DURANGO, Colo. — Pilot and scientist Steve Conley slipped behind the controls of a nimble single-engine Mooney aircraft and took to the air over the Four Corners region of the U.S. West as part of a quest to find the sources of a mysterious methane hot spot detected over the area from space.
Flying at about 2,000 feet, he banked hard left to circle the ventilation shaft of a coal mine as inlet tubes under the right wing of the aircraft sucked in air, which passed through equipment that detects and quantifies methane and provides results in real time.
“That’s a huge spike right there. It’s scary big,” said Conley as the instruments registered more than four times the background level downwind of the vent shaft, about 25 miles southwest of Durango. “That means that this thing is blowing out stuff like crazy.”
Conley is part of a team of top atmospheric scientists taking part in a high-stakes hunt for the sources of a vast methane plume billowing over the hydrocarbon-soaked San Juan Basin, more commonly known as the Four Corners area of Arizona, Colorado, New Mexico and Utah. The cloud was brought to public attention by NASA and University of Michigan scientists last year in a headline-grabbing study that drew on data gathered by a European Space Agency satellite from 2003 to 2009.
It revealed releases of methane, a powerful greenhouse gas, equivalent to more than the weight of the Empire State Building for each of the years observed, although its observations were not detailed enough to reveal the sources. Follow-up research in April by scientists with NASA and the National Oceanic and Atmospheric Administration (NOAA) made available to Al Jazeera America has identified a trove of natural and anthropogenic, or human-produced, methane sources — including that coal mine, which was measured belching out more than a ton of the gas every hour — in the San Juan Basin. Quantifying the contribution from each will take months.
“We’re seeing a lot of interesting signals. There’s going to be a lot of work for us to really try and understand what we see,” said Andrew Aubrey of NASA’s Jet Propulsion Lab at the team’s field headquarters in a hangar at the Durango–La Plata County Airport, from which a fleet of five research aircraft flew sorties. Likely suspects include venting from abundant oil and gas operations in the San Juan Basin as well as coal mines and seepage from natural coal outcrops. Other local methane emitters also include coal power plants, landfills and cattle.
The study is being conducted as Barack Obama’s administration seeks to curb emissions of methane this year as part of its commitment to mitigate climate change. Its results, which are not expected to be released until 2016, will be closely watched by the oil and gas industry, regulators, environmentalists and residents of the region, which is home to several American Indian tribes.
As part of an air and ground campaign, scientists from NASA’s Jet Propulsion Laboratory flew over the basin last month in two aircraft equipped with remote infrared imaging spectrometers, which analyzed reflected sunlight to detect and locate methane emissions. Researchers generated a map of large sources, then zeroed in on individual emitters in the area. NOAA aircraft — among them the Mooney flown by Conley, a contractor with Scientific Aviation, a private company — measured methane concentrations downwind of these sources to provide estimates of their emission rates.
Flying in tight circles around the mine facility, Conley measured methane upwind and downwind of the vent at various altitudes, tallying a spot emission rate that he said was equivalent to the weight of a Volkswagen Beetle every hour. “This one source was the largest emission rate that we’ve measured,” said Conley, who has a doctorate in atmospheric science from the University of California at Davis. “It’s a huge emitter, a huge source of methane ... In preliminary numbers, it’s what I’d call scary.”
Sampling on the ground, Petron and research assistant Eryka Thorley detected a strong signal at a gas compressor in northwestern New Mexico that was more than 30 times the background level and took several samples for subsequent laboratory chemical analysis. A gust of hydrogen sulfide made sample collection potentially hazardous, and the small research team was on notice to leave the area swiftly.
The study is being conducted amid a gathering push to curb emissions of methane, a potent greenhouse gas that traps 25 times as much heat as carbon pollution over the course of a century. Colorado last year became the first U.S. state to require companies to find and fix methane leaks and install capture 95 percent of emissions of methane and smog-forming volatile organic compounds.
In January of this year Obama took up regulation at the federal level, laying out plans to cut emissions from new gas wells by up to 45 percent by 2025 as part of a push to curb climate change and cut down on wasted energy. To meet that goal, the Environmental Protection Agency will issue a proposal affecting oil and gas production in coming months, and the Department of the Interior will update its standards for drilling to reduce leakage from wells on public lands.